Refuting Creationism - How Butterflies Evolved Dark Wing Patterns Millions of Years Before 'Creation Week'

Heliconius erato showing mosaic mutations for the ivory incRNA

Genomic dark matter solves butterfly evolutionary riddle | Media Relations | The George Washington University

Heliconius erato with one wing (right) altered by CRISPR gene. Dorsal view

Luca Livraghi.

Heliconius erato with one wing (right) altered by CRISPR gene. Ventral view

Luca Livraghi.

This is one of those research papers that creationists traditionally misrepresent as 'proving' that something biologists have long known about is wrong, and so it somehow discredits the entire body of science, and, in this specific case, that the existence of RNA that is non-coding but functional, somehow proves there is no such thing as 'junk' DNA.

In reality, of course, it simply shows us that sometimes, evolution happens in unexpected ways.

The assumption, which is almost always valid and based on sound scientific evidence, is that DNA is transcribed into messenger RNA (mRNA) that mRNA is transcribed by ribosomes into proteins. Proteins then serve functions such as structural proteins or as enzymes catalysing chemical processes in the cell. In the special case of so-called homeobox genes (hox genes) these have a regulatory function in a developing embryo, stimulating groups of cells to organise into specific tissues such as limbs, eyes and other specialised tissues, by switching other genes off and on at certain times.

Fine-Tuned Fallacy Exposed - How Earth's Ecosystems Caused Multiple Mass Extinctions Between 185 And 85 Million Years Before 'Creation Week'

Fossils of Crinoids that were probably killed in an Oceanic Anoxic Event

Credit: Professor Tom Gernon

Land-sea tag-team devastated ocean life millions of years ago reveal scientists | University of Southampton

It can only be by remaining wilfully ignorant of the history of life on Earth and how it has been affected by catastrohic changes, that creationists are able to maintain the childish delusion that Earth is somehow fine-tuned for life, and especially their life.

The fact that very much of the surface of Earth, such as oceans, deserts and high mountain ranges is lethal without special equipment, and without cloths, shelter and fire , most of the northern and southern latitudes are not survivable in an average winter should be a clue to the fallacy of the claim, but then, from the safety of small town, Bible Belt America, where the rest of the world might as well not exist, such places can be safely ignored.

But the fact remains, whether ignored or not, that there have been several periods in the history of life on Earth that the planet has become a very hostile place, resulting in mass extinctions wheree life looked as though someone had hit the reset button. The primary cause of these fluctuations is almost certinly plate techtonics which, through mid-ocean ridge activity, release sulphates and phosphates which produce blooms of plankton which then die, locking up carbon and producing anoxic sediments on the ocean bed, and by releasing CO₂ into the atmosphere where if causes a rise in ocean temperature.

Volcanic activity also produces basalt which, when eroded and washed into the sea adds to the phosphates which produce planktonic blooms and subsequent deoxygenation.

How these terrestrial and marine sources act together to produce the frequent OAEs has now been explained.

Refuting Creationism - Why The Gaps In The Fossil Record Are Not A Problem For Darwin's Theory Of Evolution

Darwin’s fear was unjustified: writing evolutionary history by bridging the gaps - News - Utrecht University

Creationists have been fooled by their cult into believe several absurdities concerning Charles Darwin and the Theory of Evolution.

The first is that the study of evolution consists of learning what Charles Darwin wrote in 1859, as though he was some sort of infallible prophet, in much the same way that religious people learn their religion by studying copies of ancient manuscripts and the writings of venerated early theologians.

The second is that the Theory of Evolution (TEO) is all about the fossil record.

The third is that Darwin claimed a whole series of intermediate fossils would be found for every evolved species, so it follows that any 'missing' fossils are failures of the Theory of Evolution and are fatal to the theory.

Charles Darwin of course was primarily a biologist, not a geologist so his understanding of the fossil record was based on observation, not necessarily on an understanding of the processes of fossilisation and why they are rare. No-one in their right mind would imagine there is some fundamental law at work which requires every generation of every evolving species to deposit a fossil where it can easily be found, and Darwin never made any claim about such unbroken series existing, only that fossils would conform to the theory that species have evolved over time.

But the gaps in the fossil record are largely irrelevant today anyway, since the fossil record is mere confirmation of the TOE, just as Darwin predicted, while the major supporting evidence comes from genetic evidence of which Darwin knew nothing, the nested hierarchies of cladistics which is the morphological evidence, biogeography which shows distribution patterns as the TOE predicts, embryology which 'reruns' evolution such as the beginnings of gills in mammalian embryos and the same sequences of cell specialisations in distantly related species.

What is the main evidence for the Theory of Evolution? The Theory of Evolution is supported by a wide range of evidence from various scientific disciplines. The main categories of evidence for evolution include:

1. Fossil Record
   • The fossil record provides a chronological catalog of life on Earth. Fossils show a gradual change in species over time, including the appearance of transitional forms that bridge gaps between major groups of organisms. For example, the transition from fish to amphibians is well-documented by fossils such as Tiktaalik, which shows features of both fish and tetrapods.
   • Fossils also show patterns of extinction and the emergence of new species, supporting the idea of descent with modification over millions of years.
   
   
2. Comparative Anatomy
   • The study of anatomical structures reveals similarities between different species that suggest a common ancestry. For example, the forelimbs of humans, whales, birds, and bats have different functions (grasping, swimming, flying), but they share a common skeletal structure, known as homologous structures, indicating they evolved from a common ancestor.
   • Vestigial structures, like the human appendix or the pelvic bones in whales, are remnants of features that were functional in an ancestor but are now reduced or repurposed, further supporting evolutionary change over time.
   
   
3. Genetics and Molecular Biology
   • DNA and molecular evidence provide some of the most compelling evidence for evolution. All living organisms use DNA as the hereditary material, and many genes are conserved across species. For instance, humans share about 98-99% of their DNA with chimpanzees, suggesting a recent common ancestor.
   • Molecular clocks, which measure the rate of genetic mutations over time, help trace the evolutionary timeline and relationships between species.
   • The presence of "junk" DNA and shared genetic sequences (such as pseudogenes) among related species suggests a common origin.
   
   
4. Biogeography
   • The geographic distribution of species provides evidence for evolution. Similar species are often found in regions that were once connected or are separated by barriers that limit gene flow, such as oceans or mountain ranges.
   • The distinct species found on islands, such as the finches on the Galápagos Islands studied by Charles Darwin, evolved from a common ancestor and adapted to different environments, illustrating adaptive radiation.
   
   
5. Embryology
   • The study of embryos shows that related species often go through similar stages of development. For example, vertebrate embryos (fish, amphibians, reptiles, birds, mammals) all have pharyngeal pouches and tails at some stage, which reflects their common ancestry.
   • Differences that arise later in development correspond to the adaptations of each species, supporting the idea of descent with modification.
   
   
6. Direct Observation of Evolutionary Processes
   • Evolution can be observed directly in nature and laboratories. Examples include the development of antibiotic resistance in bacteria, pesticide resistance in insects, and changes in beak shapes of finches in response to environmental changes.
   • Artificial selection, such as the breeding of dogs or crops, also demonstrates how selection pressures can lead to rapid changes in species over relatively short periods.
   
   
7. Radiometric Dating
   • Radiometric dating methods, such as carbon dating and uranium-lead dating, provide estimates of the age of fossils and geological formations. These methods help place fossils within a timeframe consistent with the evolutionary timeline, confirming that older fossils belong to simpler organisms, while younger fossils show more complex life forms.
   
   
8. Phylogenetics
   • The study of evolutionary relationships through phylogenetic trees, constructed based on genetic, morphological, and biochemical data, helps map the evolutionary history of species. These trees show how species diverged from common ancestors and how closely or distantly related they are.

Conclusion

These lines of evidence, taken together, provide a comprehensive framework that supports the Theory of Evolution. Each category of evidence converges to confirm that all species are related through common descent and have evolved over time through natural processes like mutation, natural selection, genetic drift, and gene flow.

Creationists claim there is no evidence for 'macro-evolution'. Is this claim valid?

The claim by creationists that there is "no evidence for macro-evolution" is not valid according to the scientific consensus. Scientists define "macro-evolution" as large-scale evolutionary changes that occur over long periods, leading to the emergence of new species, genera, families, and higher taxonomic groups. This process involves the accumulation of genetic changes that eventually result in speciation — the splitting of one species into two or more distinct species.

Here is why the claim that there is no evidence for macro-evolution is not supported:

1. Fossil Record
   • Transitional Fossils: The fossil record contains numerous examples of transitional forms that demonstrate macro-evolutionary changes. These fossils show intermediate characteristics between different groups of organisms. Notable examples include:
   • Tiktaalik: A transitional form between fish and early amphibians, showing both fish-like features (fins, scales) and tetrapod-like features (a neck, wrist bones).
   • Bird Evolution: Fossils like Archaeopteryx and Microraptor show traits of both non-avian dinosaurs and birds, documenting the evolution of birds from theropod dinosaurs.
   • Mammalian Evolution: The transition from reptiles to mammals is well-documented with fossils such as Cynognathus and Morganucodon, showing the gradual evolution of mammalian features such as a differentiated jaw and specialized teeth.
   • Human Evolution: Fossils such as Australopithecus afarensis ("Lucy") and Homo habilis demonstrate the gradual transition from early primates to modern humans, showing changes in brain size, bipedalism, and tool use.
   
   
2. Genetics and Molecular Evidence
   • Genomic Data: DNA evidence strongly supports macro-evolution. For example, comparisons of genomes between different species show patterns of genetic similarity that correspond with evolutionary relationships. Humans share a significant percentage of their DNA with other primates, such as chimpanzees (98-99%), suggesting a common ancestor.
   • Endogenous Retroviruses (ERVs): Certain retroviruses integrate into the host genome, and these viral sequences can be inherited. ERVs are found in the same locations across the genomes of related species, which would be highly unlikely unless they shared a common ancestor.
   • Gene Duplication and Diversification: Macroevolution is supported by observations of gene duplication, where new genes can evolve new functions, leading to the development of novel traits and the divergence of species over time.
   
   
3. Observed Speciation Events
   • Speciation in Real-Time: There are numerous documented cases of speciation (the formation of new species) occurring in nature, especially in organisms with short generation times. Examples include:
   • Cichlid Fish in African Lakes: These fish have diversified into hundreds of species with distinct characteristics in a relatively short period.
   • Polyploidy in Plants: Many new plant species have arisen through polyploidy, where an organism gains extra sets of chromosomes, creating reproductive barriers with the parent species.
   • Apple Maggot Flies (Rhagoletis pomonella): This insect species has been observed to split into distinct populations based on host plant preference, a process that could lead to speciation.
   
   
4. Comparative Anatomy and Embryology
   • Homologous Structures: Similarities in bone structures, like the limbs of vertebrates, indicate common ancestry. The differences between these structures have accumulated over time, leading to macro-evolutionary changes.
   • Developmental Biology: Embryonic development patterns often reveal similarities across species that are not apparent in adult forms. For instance, the presence of gill-like structures in the embryos of vertebrates (including humans) suggests a common origin with fish.
   
   
5. Phylogenetic Evidence
   • Evolutionary Trees: Phylogenetic trees constructed using genetic, morphological, and biochemical data consistently show that species have diverged from common ancestors. These trees reflect branching patterns predicted by macro-evolutionary theory.
   
   
6. Mechanisms for Large-Scale Evolutionary Change
   • The mechanisms that drive microevolution (small-scale changes within species) — such as mutation, natural selection, genetic drift, and gene flow — are the same processes that, over extended periods, result in macro-evolutionary changes. There is no scientific barrier that separates microevolution from macroevolution; rather, macroevolution is the accumulation of many microevolutionary changes.

Conclusion

The claim that there is "no evidence for macro-evolution" reflects a misunderstanding or rejection of the broad range of scientific evidence supporting the process. The fossil record, genetic data, observed speciation events, comparative anatomy, and phylogenetic studies all provide robust evidence for macro-evolution. In science, macroevolution is a well-established process, substantiated by multiple independent lines of evidence from different fields.

In actual fact, Chares Darwin accepted that the fossil record was at best gappy with:

One other consideration is worth notice: with animals and plants that can propagate rapidly and are not highly locomotive, there is reason to suspect, as we have formerly seen, that their varieties are generally at first local; and that such local varieties do not spread widely and supplant their parent-forms until they have been modified and perfected in some considerable degree. According to this view, the chance of discovering in a formation in any one country all the early stages of transition between any two forms, is small, for the successive changes are supposed to have been local or confined to some one spot. Most marine animals have a wide range; and we have seen that with plants it is those which have the widest range, that oftenest present varieties; so that with shells and other marine animals, it is probably those which have had the widest range, far exceeding the limits of the known geological formations of Europe, which have oftenest given rise, first to local varieties and ultimately to new species; and this again would greatly lessen the chance of our being able to trace the stages of transition in any one geological formation.

It should not be forgotten, that at the present day, with perfect specimens for examination, two forms can seldom be connected by intermediate varieties and thus proved to be the same species, until many specimens have been collected from many places; and in the case of fossil species this could rarely be effected by palaeontologists.

We shall, perhaps, best perceive the improbability of our being enabled to connect species by numerous, fine, intermediate, fossil links, by asking ourselves whether, for instance, geologists at some future period will be able to prove, that our different breeds of cattle, sheep, horses, and dogs have descended from a single stock or from several aboriginal stocks; or, again, whether certain sea-shells inhabiting the shores of North America, which are ranked by some conchologists as distinct species from their European representatives, and by other conchologists as only varieties, are really varieties or are, as it is called, specifically distinct. This could be effected only by the future geologist discovering in a fossil state numerous intermediate gradations; and such success seems to me improbable in the highest degree.

Geological research, though it has added numerous species to existing and extinct genera, and has made the intervals between some few groups less wide than they otherwise would have been, yet has done scarcely anything in breaking down the distinction between species, by connecting them together by numerous, fine, intermediate varieties; and this not having been effected, is probably the gravest and most obvious of all the many objections which may be urged against my views.

Darwin, Charles. On the Origin of Species By Means of Natural Selection, or, the Preservation of Favoured Races in the Struggle for Life (p. 159). Public Domain Books. Kindle Edition.

From that concluding paragraph, it is obvious that Darwin was less worried about the perceived gaps than about how they would be used to discredit his theory.

And now a team of researchers from Utrecht, Netherlands and Liverpool, UK, have shown that the gaps in the fossil records are not an unsurmountable problem for the TOE because they can easily be bridged with other evidence. Their findings are the subject of a recent paper in BMC Ecology and Evolution and a news release from Utrecht University:

Darwin’s fear was unjustified: writing evolutionary history by bridging the gaps

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Fossils are used to reconstruct evolutionary history, but not all animals and plants become fossils and many fossils are destroyed before we can find them (e.g., the rocks that contain the fossils are destroyed by erosion). As a result, the fossil record has gaps and is incomplete, and we’re missing data that we need to reconstruct evolutionary history. Now, a team of sedimentologists and stratigraphers from the Netherlands and the UK examined how this incompleteness influences the reconstruction of evolutionary history. To their surprise, they found that the incompleteness itself is actually not such a big issue.

It’s as if you are missing half of a movie. If you are missing the second half, you can’t understand the story, but if you are missing every second frame, you can still follow the plot without problems.

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The regularity of the gaps, rather than the incompleteness itself, is what determines the reconstruction of evolutionary history. If a lot of data is missing, but the gaps are regular, we could still reconstruct evolutionary history without major problems, but if the gaps get too long and irregular, results are strongly biased.

Niklas Hohmann, lead author
Faculty of Geosciences
Department of Earth Sciences
Utrecht University, Utrecht, The Netherlands.

Darwin
Since Charles Darwin published his theory of evolution, the incompleteness of the fossil record has been considered problematic for reconstructing evolutionary history from fossils. Darwin feared that the gradual change that his theory predicted would not be recognizable in the fossil record due to all the gaps.

Our results show that this fear is unjustified. We have a good understanding of where the gaps are, how long they are and what causes them. With this geological knowledge, we can reconstruct evolution hundreds of millions of years ago at an unprecedented temporal resolution.

Niklas Hohmann.

Simulations
Computer simulations of geological processes at timescales longer than any historical records can be used to examine the effects of the incompleteness. To that end, Hohmann and his team combined simulations of different modes of evolution with depositions of carbonate strata to examine how well the mode of evolution can be recovered from fossil time series, and how test results vary between different positions in the carbonate platform and multiple stratigraphic architectures generated by different sea level curves.

If Darwin could read the article, he would certainly be relieved: his theory has proven to be robust on the vagaries of the rock record. Deep-time fossil data – however incomplete – supports our understanding of the mode and tempo of evolution.

Niklas Hohmann.

Article

Hohmann, Niklas; Koelewijn, Joël R.; Burgess, Peter; Jarochowska, Emilia
Identification of the mode of evolution in incomplete carbonate successions BMC Ecology and Evolution 24, 113 (2024), https://doi.org/10.1186/s12862-024-02287-2

Abstract

Background

The fossil record provides the unique opportunity to observe evolution over millions of years, but is known to be incomplete. While incompleteness varies spatially and is hard to estimate for empirical sections, computer simulations of geological processes can be used to examine the effects of the incompleteness in silico.

We combine simulations of different modes of evolution (stasis, (un)biased random walks) with deposition of carbonate platforms strata to examine how well the mode of evolution can be recovered from fossil time series, and how test results vary between different positions in the carbonate platform and multiple stratigraphic architectures generated by different sea level curves.

Results
Stratigraphic architecture and position along an onshore-offshore gradient has only a small influence on the mode of evolution recovered by statistical tests. For simulations of random walks, support for the correct mode decreases with time series length.

Visual examination of trait evolution in lineages shows that rather than stratigraphic incompleteness, maximum hiatus duration determines how much fossil time series differ from the original evolutionary process. Gradual directional evolution is more susceptible to stratigraphic effects, turning it into punctuated evolution. In contrast, stasis remains unaffected.

Conclusions

• Fossil time series favor the recognition of both stasis and complex, punctuated modes of evolution.
• Not stratigraphic incompleteness, but the presence of rare, prolonged gaps has the largest effect on trait evolution. This suggests that incomplete sections with regular hiatus frequency and durations can potentially preserve evolutionary history without major biases. Understanding external controls on stratigraphic architectures such as sea level fluctuations is crucial for distinguishing between stratigraphic effects and genuine evolutionary process.

Introduction

The fossil record as source of information
Fossils provide a unique record of evolution on temporal and spatial scales not accessible to experimentation or direct human observation [23, 24]. Geological records have delivered fossil time series crucial in formulating and testing hypotheses on evolutionary dynamics and mechanisms of speciation spanning micro- to macroevolutionary scales (e.g., [3, 22, 87, 92]). Nevertheless, fossils remain underused in evolutionary biology. Their main application is still node and tip calibration of molecular clocks, which commonly relies on single occurrences or on assumptions about the probability of finding a fossil rather than stratigraphic data [17]. It is also subject to biases resulting from this small sample size [84]. The unique type of information contained in a fossil succession sampled over a long time interval is rarely exploited, likely due to the following barriers:

1. The fossil record, being a part of the stratigraphic record, is patchy and distorted. At the time when Darwin [15] discussed this as a major limitation for the testing and development of the theory of evolution, little geological knowledge was present to elucidate the rules governing this incompleteness. Darwin’s concern widely persists (e.g., Patterson [73]), albeit mostly implicitly: most phylogenetic analyses published today do not use fossils which would have been relevant or use only a small fraction of them. Stratigraphy and sedimentology, which can provide relevant data on fossils and the constraints on their occurrence and sampling [46, 56], are jargon-laden, highly atomized disciplines whose utility for evolutionary biology is not obvious to biologists. Biostratigraphy, which uses fossils to establish the relative age of rocks and has amassed datasets that would be of high utility for evolutionary studies, employs taxonomic concepts that are often impractical for or incompatible with evolutionary questions [19, 20, 33, 75]. As a results, scientific communities studying evolution and the fossil record function in parallel, with limited exchange [30].
2. There is a lack of methodological frameworks to incorporate fossils in their stratigraphic context in evolutionary studies. Historically, phylogenetic methods rarely incorporated geological information such as the relative order of appearance of taxa or specimens in the fossil record, which is the main subject of biostratigraphy [100]. This has led to radical discrepancies between the outcomes of phylogenetic and stratigraphic, or stratophenetic, approaches [26, 18, 22]. This barrier is gradually overcome by methodological advances, such as the Fossilized Birth-Death Model [85], which allows incorporation of parameters specific to the fossil record, such as fossilization rate, sampling probability and age uncertainties of fossil occurrences [5, 6, 95, 101].

Recently, there is renewed appreciation for the importance of fossils in phylogenetic reconstructions [31, 70, 71, 80]. These studies focus on the role of the morphological information provided by extinct taxa, but less on what a modern understanding of the physical structure of the geological record contributes to reconstructing evolutionary processes from fossil-bearing stratigraphic successions.

Stratigraphic incompleteness and age-depth models
The incompleteness of the fossil record serves as an umbrella term for different effects that diminish the information content of the rock record, ranging from taphonomic effects and sampling biases to the role of gaps and erosion [56]. Here we focus on the role of gaps (hiatuses) in the rock record. Such gaps can arise due to sedimentation (including fossils) and subsequent erosion or lack of creation of rocks in the first place, e.g., when an environment remains barren of sediment formation or supply for a long time. Both processes result in gaps in the rock record and, as a result, in the fossil record. This type of incompleteness is termed stratigraphic (in)completeness, defined as the time (not) recorded in a section, divided by the total duration of the section [16, 88]. Stratigraphic completeness provides an upper limit on the proportion of evolutionary history that can be recovered from a specified section, even with unlimited resources and perfect preservation of fossils. Stratigraphic completeness is difficult to quantify in geological sections, and estimates range between 3 and 30% [98], suggesting that more than 70% of evolutionary history is either not recorded in the first place or destroyed at a later time.

Fossils older than a 1.5 million years cannot be dated directly, and their age has to be inferred from circumstantial evidence on the age of the strata in which they were found [56, 97]. This inference is formalized by age-depth models (ADMs), which serve as coordinate transformations between the stratigraphic domain, where the fossils were found (length dimension L, SI unit meter), and the time domain (time dimension T, SI unit seconds - we use the derived units years, kyrs, or Myrs) [37]. Age-depth models are always explicitly or implicitly used when fossil data is used for evolutionary inferences. Because they convey how positions of fossils relate to their age, ADMs are the basis for calculating evolutionary rates. As a result, revising ADMs commonly leads to a revision of evolutionary rates. For example, Malmgren, Berggren, and Lohmann [64] observed increased rates of morphological evolution in lineages of fossil foraminifera over a geologically short time interval of 0.6 Myr and proposed that this “punctuated gradualism” may be a “common norm for evolution”. MacLeod [63] revised the age-depth model and showed that the interval with increased rates of evolution coincides with a stratigraphically condensed interval, i.e., more change is recorded in a thinner rock unit. Re-evaluating the evolutionary history based on the revised age-depth model removed the apparent punctuation and showed that morphological evolution in that case had been gradual rather than punctuated.

Age-depth models contain information on both variations in sediment accumulation rate and gaps in the stratigraphic and - as a result – the fossil record. For example, stratigraphic completeness corresponds to the fraction of the time domain to which an age-depth model assigns a stratigraphic position. In the absence of an age-depth model, we can only make statements on the ordering of evolutionary events, but not on the temporal rates involved.

Forward models of stratigraphic architectures
Forward computer simulations of sedimentary strata provide a useful tool to study the effects of incompleteness and heterogeneous stratigraphic architectures. They have demonstrated that locations and frequency of gaps in the stratigraphic record are not random, but a predictable result of external controls, such as fluctuations in eustatic sea level [12, 67, 96].

Combined with biological models, forward models provide a powerful tool to test hypotheses on the effects of stratigraphic architectures on our interpretations of evolutionary history. For example, Hannisdal [32] combined simulations of a siliciclastic basin with models of taphonomy and phenotypic evolution. The results showed that when sample sizes are small, morphological evolution will appear as stasis regardless of the underlying mode. This might explain why stasis is the most common evolutionary pattern recovered from the fossil record [45].

Stratigraphic incompleteness and variations in sediment accumulation rates introduce multiple methodological challenges. Constructing complex ADMs requires sedimentological and stratigraphic expert knowledge, and they will potentially be associated with large uncertainties. Even in the “perfect knowledge” scenario where the age-depth model is fully known, evolutionary history in the time domain will inevitably be sampled irregularly: If two samples are separated by a hiatus, their age difference must be at least the duration of the hiatus, which might be millions of years. On the other hand, if sediment accumulation is rapid and no hiatuses are present, the age difference between samples might be only a few days.

Most studies “translate” fossil successions into time series using age-depth models based on simplified assumptions on the regularity of the stratigraphic record. These ADMs ignore stratigraphic incompleteness and often assume uninterrupted constant sediment accumulation (UCSA). This assumption implies that stratigraphic completeness is 100%, rock thickness is proportional to time passed, and linear interpolation between tie points of known age can be used to infer fossil ages from their positions. Such ADMs are usually used implicitly, without discussing their limitations. While the assumption of UCSA is sedimentologically and stratigraphically unrealistic, it brings strong methodological simplifications. For example, if distance between samples collected in a rock section is kept constant, UCSA implies that the underlying evolutionary history in the time domain is sampled at a constant frequency, the generated fossil time series are equidistant in time and can therefore be analyzed by standard methods of time series analysis [7, 45].

Objectives and hypotheses
We examine how commonly made simplified assumptions on stratigraphic architectures influence how the mode of evolution is recovered from fossil time series. We use tropical carbonate platforms as a case study, because they host large parts of the fossil record and are evolutionary hotspots [51].

We test the following hypotheses:

1. The mode of evolution identified in a fossil time series obtained under the assumption of uninterrupted constant sediment accumulation (UCSA) is the same as the mode of the original time series.
2. Lower stratigraphic completeness reduces the chance of identifying the correct mode of evolution from fossil time series constructed based on the assumption of UCSA [41, 43]. The implication of this hypothesis is that different depositional environments have different chances of preserving the mode of evolution because of systematic differences in their completeness.

[…]

Conclusions
We tested the hypothesis that the commonly employed approach to identifying the mode of evolution in fossil succession, i.e., linear projection of stratigraphic positions of occurrences into the time domain without considering changes in sedimentation rate and gaps in the record, recovers the correct mode of evolution. We found that, although prolonged gaps distorted trait evolution record visually, tests for the mode of evolution were only weakly affected by gaps and irregular age-depth models. Our findings differ from those of Hannisdal [32], who found (using a different approach but asking the same question) that incomplete sampling in the stratigraphic record may result in all other modes of evolution being identified as stasis.

Our findings did not vary substantially between two stratigraphic architectures with varying gap distributions and degrees of stratigraphic completeness. The lack of influence of stratigraphic effects is counterintuitive, as deeper environments are often assumed to be more complete and therefore more suitable for sampling fossil series for evolutionary studies. In the case of undirected random walks, increasing the number of observations (i.e., sampling intensity, length of the fossil series) did not improve the identification of the mode of evolution, but rather worsened it.

Our study was motivated by improving the recovery of evolutionary information from highly resolved fossil successions, particularly at microevolutionary scales. We are convinced that such successions can aliment models and understanding that is not accessible to exclusively neontological methodologies, as illustrated by e.g. [44, 77, 90]. Our contribution is the use of stratigraphic forward modeling to ground-truth the methodologies serving this palaeobiological research program. Forward modeling allows rigorous testing of concerns that the fossil record is too distorted, or too incomplete, to answer (micro)evolutionary questions. They also offer the possibility to evaluate the robustness of identifications of the mode of evolution and estimates of its parameters under different simulated age-depth models. Finally, sedimentological information may aliment age-depth models [36, 52]. The proliferation of ever better stratigraphic forward models (e.g. CarboCAT [12, 67], SedFlux [50], strataR [42], CarboKitten.jl [34]) opens the possibility to validate these methods and improve our understanding of the fossil record.

Fig. 1

Study design for testing the mode of evolution in the stratigraphic domain. Computationally, first sampling positions are determined, then the age-depth model is used to determine the times that correspond to these positions. Last, the trait evolution at said times are simulated. The simulated mean trait values are the values observable at the sampled stratigraphic positions

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Fig. 1

The outcome of simulating carbonate platforms in the stratigraphic domain. A Scenario A: deposition based on a fictional sea-level curve. B Scenario B: deposition based on the sea-level curve from Miller et al. [69] for the last 2.58 Myr. Graphs represent the position in the middle of the simulated grid along the strike

Hohmann, N., Koelewijn, J.R., Burgess, P. et al.
Identification of the mode of evolution in incomplete carbonate successions. BMC Ecol Evo 24, 113 (2024). https://doi.org/10.1186/s12862-024-02287-2

Copyright: © 2024 The authors.
Published by BioMed Central Ltd (Springer Nature Ltd.) Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

In summary, what this study shows is that when computer models are used to predict the course of evolution in a geological column in which what fossils there are show how environmental changes result in morphological changes, the computer prediction of and the fossil record match. This means that temporal gaps in the fossil record can be bridged and that assumptions about what happened in the gap are valid. In other words, the gaps are not a problem for the TOE.

Additionally, since most taxonomic relationships are deduced from multiple strands of evidence, of which the fossil record may or may not feature, the 'gaps' are irrelevant anyway.

So, not only are the 'gaps' not a problem for the TOE, let alone fatal for it, the assumptions we make based on logical deductions are as valid today as they were in Darwin's day. It's clear from his writing that Darwin was more concerned about how opponents of the TOE would misrepresent the gaps in the fossil record than he was about those gaps. From the way creationist frauds fool their dupes about them, it seem Darwin was right to be concerned.

Refuting Creationism - Merging Galaxies 12.8 Billion Years Before 'Creation Week'.

Artist's impression of the interacting galaxies observed in this research

Credit: ALMA (ESO/NAOJ/NRAO),
T. Izumi et al

The interacting galaxies observed by the ALMA radio telescope at the Cosmic Dawn. This image shows the distribution of ionized carbon gas, which reflects the overall distribution and motion of interstellar matter. It is clearly visible that the two galaxies are interacting, and are connected by a structure between them. The two crosses in the image indicate the positions of the low-luminosity quasars discovered by the Subaru Telescope.

Dancing Galaxies Make a Monster at the Cosmic Dawn | NAOJ: National Astronomical Observatory of Japan - English

Creationists find the immensity of the Universe very difficult to force-fit into the creation myth in Genesis which describes it as a small flat planet with a dome over it, so they turn their putative creator god into an Almighty Liar by claiming it just made the Universe look old by placing all the photons to make it look like they started out tens of billions of years ago, when it created everything by magic just 10,000 years ago.

Strangely, they claim they can tell the Almighty Liar lied everywhere in the physical evidence that makes the Universe just look old, because they have a book in which it once told the truth!

Anyway, this is not the only contradictory belief they have to try to ignore, so they'll have no difficulty ignoring the evidence of a chaotic universe which they prefer to believe is perfectly ordered and designed with them in mind.

Malevolent Designer - How Zebra Fish Can 'Heal' Blindness - And Humans Can't

[left caption]

[right caption]

Zebrafish photoreceptor cells stimulated with blue light show correct electrical activity. The picture was taken using the microscope that was custom-built for this study.

Seeing the Future: Zebrafish Regenerates Fully Functional Photoreceptor Cells and Restores Its Vision — Center for Regenerative Therapies Dresden (CRTD) — TU Dresden

Readers may remember my recent post about how researchers have discovered that zebra fish can heal a transected spinal cord, and why creationists need to explain why their putative omnibenevolent designer apparently chose not to give this ability to all vertebrates, including its supposedly favourite special vertebrate, humans
.
Was it because it prefers to watch paraplegics suffer or because it forgot how to?

Well, now we have more evidence, if you accept the childish creationist 'intelligent [sic] design, nonsense, of how the same fish, have apparently been given another ability that would have hugely benefitted humans and other animals - they can repair damage to their visual receptors in their eyes, in other words, they can heal blindness.

A believer in intelligent [sic] design, must accept that, since their designer god apparently knew how to give this ability to zebra fish, it knew how to give it to all vertebrates and made the conscious decision not to.

Creationism Refuted - A Marine Relative of Mycobacterium Tuberculosis Shares 80% Of Its Genome

Mycobacterium spongiae

Credit: Sacha J. Pidot and team

A new species of bacterium, related to Mycobacterium tuberculosis has been found living in a sponge on the Great Barrier Reef.

TB under the sea: A marine sponge microbe provides insights into the evolution of tuberculosis | Doherty Website

Tell a creationists that humans and chimpanzees have 98% of their genomes in common, and they'll tell you this doesn't prove common origins or 'macro-evolution', but show them evidence that two bacteria have evolved from a common ancestor because they have 80% of their genome in common and they'll tell you this doesn't mean they've evolved because they are both still 'bacteria kind'.

So, why doesn't 98% commonality mean humans and chimpanzees are both still 'ape kind'?

But the evidence that the two bacteria, Mycobacterium tuberculosis, and the newly-discovered M. spongiae is compelling, and gives a clue as to the origins of M. tuberculosis, one of the most deadly pathogenic bacteria, possibly from marine origins.

Creationism Refuted - What a Mallorcan Cave Tells Us Of Events Before 'Creation Week'.

Bogdan Onac studies the phreatic overgrowths seen in this photo. They grow exactly at sea level and offer a more accurate reconstruction of past sea level history. He used these to determine the age of the submerged bridge.

Photo: M.À. Perelló

This article is best read on a laptop, desktop or tablet

Close-up view of the submerged stone bridge from Genovesa Cave, Mallorca, Spain

Photo: R. Landreth

What a submerged ancient bridge discovered in a Spanish cave reveals about early human settlement

The Spanish Balearic Island of Mallorca (Majorca), a favourite holiday destination for Brits looking for sun, sea and sand, is composed largely of limestone which lends itself to cave formation and limestone caves lend themselves to stalactite formation.

They also provided shelters for early humans, so the evidence of human presence gives us a good picture of the timing of human migration into the area.

Like 99,9975% of Earth's history, the events recorded in these Mallorcan caves happened in the long pre-'Creation Week' history, long before creationists believe Earth was made out of nothing by magic.

Readers may recall my recent blog post concerning what is known of the changes in biodiversity as the Mediterranean dried up, then flooded again about 5.5 million years ago due to plate tectonic movements. These Mallorcan caves formed after those catastrophic events but still well before creationism's 'Creation Week'.

The stalactites in one cave in particular, the Genovesa Cave at the eastern end of the island hold a record of sea-level changes that correlate with known periods of glaciation and interglacial warmer periods. During periods of glaciation, water was locked up in polar ice and glaciers, so sea-levels fell.

What information do you have on the Genovesa Cave in Mallorca, Spain, and what it tells us of sea-level changes? Genovesa Cave, located on the eastern coast of Mallorca, Spain, is a notable site for studying past sea-level changes due to its unique speleothem formations (such as stalactites and stalagmites) and its position relative to current sea levels.

Key Information About Genovesa Cave

1. Geological Context:
   • Genovesa Cave is a partially submerged cave system found on the island of Mallorca, part of the Balearic Islands in the western Mediterranean Sea.
   • The cave has been naturally formed in limestone rock, a type of carbonate rock that is particularly responsive to changes in sea level.
   
   
2. Evidence of Past Sea-Level Changes:
   • Speleothem Growth Stages: The most significant evidence for past sea-level changes comes from speleothems, which are mineral deposits formed in caves by the precipitation of carbonate minerals from dripping water. When sea levels rise, the cave becomes submerged, and speleothem growth ceases due to a lack of contact with air. When sea levels fall, the cave is re-exposed to air, allowing speleothems to grow again.
   • Dating Techniques: Researchers use uranium-thorium (U-Th) dating methods to date these speleothems accurately. The growth and cessation periods can be correlated with known global sea-level fluctuations, such as those associated with glacial and interglacial cycles during the Quaternary period (the last 2.6 million years).
   
   
3. Sea-Level Highstands and Lowstands:
   
   
   • Studies of Genovesa Cave have identified speleothems that formed during several past interglacial periods when sea levels were higher than today. This provides evidence for higher sea levels during warm periods such as the Last Interglacial (about 125,000 years ago).
   • Conversely, periods when the cave was submerged or when speleothem growth was halted correspond to glacial periods when sea levels were much lower, sometimes up to 120 meters lower than the current level.

Implications for Understanding Sea-Level Changes

1. Local and Global Sea-Level Correlation:
   • The data obtained from Genovesa Cave speleothems align well with global records of sea-level changes, such as those derived from coral reefs and marine terraces. This reinforces the idea that the cave provides a reliable local record that reflects broader, global sea-level trends.
   
   
2. Understanding the Mediterranean Sea's Response:
   • The cave's findings contribute to our understanding of how the Mediterranean Sea responded to global climatic events. During periods of rapid deglaciation, for example, meltwater pulses could have caused rapid sea-level rises, which would be recorded in the cave's geological formations.
   
   
3. Insights into Future Sea-Level Rise:
   • Studying past sea levels helps scientists predict future changes, particularly in the context of global warming and potential ice sheet melting. The high-resolution records from Genovesa Cave can help refine models of future sea-level rise, especially in understanding how fast and how much sea levels could change.

In Summary

Genovesa Cave in Mallorca is a critical natural archive for studying past sea-level changes, providing both a local record of changes in the Mediterranean and contributing to the understanding of global sea-level fluctuations. The cave's speleothem formations, when dated, tell us about the timing and extent of past sea levels, helping us predict future changes.

Did the cave exist during the Messinian Salinity Crisis and the following Zanclean flood?

Genovesa Cave, like many other karstic cave systems on Mallorca, likely did not exist in its current form during the Messinian Salinity Crisis (MSC) and the subsequent Zanclean flood. However, understanding its formation requires a bit of geological context about these events and the development of the cave.

Geological Context of the Messinian Salinity Crisis and Zanclean Flood

1. Messinian Salinity Crisis (MSC) (5.96 to 5.33 million years ago):
   • The MSC was a period when the Mediterranean Sea was largely cut off from the Atlantic Ocean due to tectonic movements, leading to extreme evaporation and a significant drop in sea level. During this time, the Mediterranean became partially or fully desiccated, creating vast salt deposits and deep erosional features (like canyons and river systems) that extended below the current sea level.
   • Sea levels were drastically lower, estimated to have dropped by as much as 1,500 meters. The drop exposed large portions of the continental shelf and caused significant erosion of the landscape, including the areas around Mallorca.
   
   
2. Zanclean Flood (5.33 million years ago):
   • The Zanclean flood marked the end of the MSC, when the Strait of Gibraltar reopened, and Atlantic waters rapidly refilled the Mediterranean basin. This event is thought to have raised sea levels in the Mediterranean by up to 1,500 meters over a short period, flooding the previously exposed and desiccated areas.

Did Genovesa Cave Exist During These Events?

1. Formation of Genovesa Cave:
   • Genovesa Cave, like many karst caves, formed much later than the Messinian Salinity Crisis and the Zanclean flood. The formation of such caves typically occurs over long periods through the dissolution of limestone by slightly acidic groundwater. This process, known as karstification, is generally linked to periods when the sea level is relatively stable and when the water table is at an appropriate level to facilitate cave development.
   • Given that the MSC was a period of extreme environmental conditions (both in terms of erosion during the desiccation and rapid flooding during the Zanclean flood), the specific geological setting that would allow for the gradual formation of karstic caves like Genovesa likely did not exist until after these events.
   
   
2. Post-MSC Karst Development:
   • After the Mediterranean was refilled and the sea level stabilized following the Zanclean flood, conditions would have been more suitable for the formation of karst systems like Genovesa Cave. The Quaternary period, which began about 2.6 million years ago, saw multiple cycles of glacial and interglacial periods, during which fluctuations in sea levels, combined with periods of stability, promoted the development of karst caves in the limestone regions of Mallorca.
   
   
3. Timing of Cave Formation:
   • The specific timing of the formation of Genovesa Cave is not precisely known, but it is generally accepted that most of the karst caves in Mallorca formed during the Pleistocene epoch (2.6 million to 11,700 years ago) or even more recently. The cave's features and deposits suggest that it has undergone several phases of exposure and submersion due to sea-level changes throughout this period, well after the MSC and Zanclean flood.

Conclusion

Genovesa Cave, in its current form, did not exist during the Messinian Salinity Crisis or the subsequent Zanclean flood. The cave likely formed much later, during the Quaternary period, as conditions became suitable for karstification following the stabilization of Mediterranean sea levels after these dramatic geological events. The MSC and the Zanclean flood were important in shaping the broader landscape of the Mediterranean region, but the specific conditions necessary for the formation of caves like Genovesa developed much later.

What are phreatic overgrowths on Speleothems (POS)?

Phreatic overgrowths on speleothems (POS) are unique mineral deposits that form in coastal cave environments at the interface between freshwater and seawater. These overgrowths are specifically associated with periods when the cave is partially submerged in a mix of fresh and saline water, typically at or near sea level. They provide important clues about past sea-level positions and climate conditions. Key Characteristics of Phreatic Overgrowths on Speleothems

1. Definition:
   • Phreatic overgrowths on speleothems are secondary carbonate deposits, typically composed of minerals like calcite or aragonite. They form on existing speleothems (such as stalactites, stalagmites, or flowstones) when the cave environment is inundated by a fluctuating water table that is influenced by sea level.
2. Formation Environment:
   • These overgrowths develop in the "phreatic zone" of caves— the zone that is below the water table and is saturated with water. In coastal caves, this zone is directly affected by sea-level changes. When sea level is stable or fluctuates within a certain range, the mixing zone between freshwater and saline water can lead to mineral precipitation on submerged speleothems.
3. Mechanism of Formation:
   • Phreatic overgrowths form due to a process known as "degassing" or "precipitation" when carbon dioxide (CO₂) dissolved in water escapes into the cave air. This loss of CO₂ from water that is saturated with calcium carbonate (CaCO₃) promotes the deposition of calcite or aragonite on existing cave formations.
   • In coastal caves, the mixing of fresh and saltwater enhances this process. Freshwater entering the cave mixes with seawater, creating conditions where minerals precipitate more readily due to changes in water chemistry, such as shifts in pH, temperature, and CO₂ concentration.
4. Morphology and Appearance:
   • Phreatic overgrowths typically form flat or gently sloping horizontal crusts, rims, or coatings on existing cave formations. Their horizontal nature reflects the stable water table level at which they formed.
   • These deposits can vary in thickness and are often found at multiple levels within the cave, corresponding to different sea levels over time.

Importance of Phreatic Overgrowths on Speleothems

1. Indicators of Past Sea Levels:
   • POS are valuable indicators of past sea levels because they form at specific elevations related to the water table, which in coastal environments is closely linked to sea level. By dating these formations using techniques such as uranium-thorium (U-Th) dating, scientists can reconstruct past sea-level positions and determine the timing and magnitude of sea-level changes over thousands to hundreds of thousands of years.
2. Understanding Paleoclimatic Conditions:
   • Beyond sea levels, POS can provide insights into broader paleoclimatic conditions. The chemical composition of these overgrowths (e.g., stable isotopes of oxygen and carbon) can offer information about past temperature, rainfall patterns, and even water source characteristics.
3. Calibrating Sea-Level Rise Models:
   • The precise dating of phreatic overgrowths helps in calibrating models of sea-level rise, particularly when cross-referenced with other geological and paleoclimatic data, such as coral reefs, marine terraces, and ice cores. This is particularly important for understanding the rate of sea-level rise in response to past climate events, such as glacial and interglacial periods.

Examples of POS Studies

• Mediterranean Caves (Mallorca, Spain): In Mallorca, POS have been extensively studied in caves like Genovesa Cave and others along the coast. These formations have been used to map out the history of Mediterranean sea-level changes over the last several hundred thousand years, including periods such as the Last Interglacial (about 125,000 years ago).
• Caribbean and Other Coastal Regions: Similar studies have been conducted in coastal caves in the Caribbean and other regions, where POS help reconstruct sea-level fluctuations and regional climate changes.

Summary

Phreatic overgrowths on speleothems are carbonate deposits formed in caves at the interface between freshwater and seawater, directly reflecting past sea levels. They serve as crucial archives for understanding past sea-level changes, climate conditions, and the complex interplay between global climate and regional environmental changes.

In the context of dating caves, what does 'A ²³²Th/²³⁸U-²³⁴U/²³⁸U-²³⁰Th/²³⁸U (plotted as a Rosholt A type) isochron age of 5479 ± 120 years B.P.' mean?

The phrase describes the result of a specific type of uranium-thorium dating method used to determine the age of materials, such as carbonate deposits in caves. Let's break down what each part of this phrase means:

Uranium-Thorium (U-Th) Dating Overview

Uranium-Thorium (U-Th) dating also known as Thorium-230 dating is a radiometric dating technique used to determine the age of calcium carbonate materials like speleothems (stalactites, stalagmites, and other cave formations). The method relies on the radioactive decay of uranium isotopes to thorium isotopes. Here's a breakdown of the isotopes involved:

• ²³⁸U (Uranium-238): The parent isotope, which decays over time into various intermediate daughter isotopes, including ²³⁴U (Uranium-234) and ²³⁰Th (Thorium-230).
• ²³²Th (Thorium-232): A stable, non-radioactive isotope of thorium that is not involved in the decay chain but can be present in the sample as a contaminant or from initial conditions.

Explanation of the Phrase

1. "²³²Th/²³⁸U-²³⁴U/²³⁸U-²³⁰Th/²³⁸U":
   • These ratios represent the proportions of different isotopes present in the sample.
     • ²³²Th/²³⁸U: Indicates the ratio of thorium-232 to uranium-238 in the sample.
     • ²³⁴U/²³⁸U: Indicates the ratio of uranium-234 (an intermediate decay product) to uranium-238.
     • ²³⁰Th/²³⁸U: Indicates the ratio of thorium-230 (the target daughter isotope) to uranium-238.
   
   
2. "Plotted as a Rosholt A type isochron":
   • An isochron is a graphical method used to determine the age of a sample by plotting the ratios of isotopes against each other. The slope of the line (the isochron) represents the time that has passed since the sample's formation.
   • "Rosholt A type" refers to a specific type of isochron plot developed by John Rosholt, which plots the ratios of these isotopes in a way that accounts for initial thorium contamination (²³²Th). This method provides a more accurate age by correcting for the presence of any initial, non-radiogenic thorium in the sample.
   
   
3. "Isochron age of 5479 ± 120 years B.P.":
   • This is the calculated age of the sample, determined by the U-Th dating method using the isochron plot.
   • 5479 years B.P.: This means "5479 years Before Present," where "Before Present" is typically defined as before the year 1950. The sample is estimated to have formed 5479 years ago.
   • ± 120 years: This represents the margin of error or uncertainty in the dating. The true age is likely within the range of 5479 years plus or minus 120 years (i.e., between 5359 and 5599 years ago).

Summary

The phrase refers to a method of dating a cave sample using uranium-thorium dating and an isochron plot (Rosholt A type) to determine that the sample is approximately 5479 years old, with an uncertainty of ±120 years. The use of multiple isotope ratios and the isochron method helps correct for initial contamination and provides a more accurate age estimate.

This allowed stalactites to grow as water containing dissolved minerals seeped through the cave roof and dripped down, evaporating as it did so, and leaving a record of rainfall. During interglacial period, sea-levels rose, submerging the caves and preventing the growth of stalactites, leaving a record of these sea-level rises.

But, apart from these records of climate and sea-level changes, the Genovesa Cave contains a more tangible record - that of human habitation on the island and so of colonisation of the Western Mediterranean and the Iberian peninsula in particular.

It is a submerged stone bridge, built when the sea-levels were lower at the height of the last ice age. The bridge was used to cross a now submerged small lake at a low point in the cave system and must have been deliberately constructed.

Scientists these days rarely, if ever, set out to refute creationist mythology but all do so incidentally, simply by doing what good science does and discovering the facts, and this discovery, by speleogeologists from the University of South Florida, does just that. It is the subject of a recent open access paper in Communications Earth & Environment and a recent news release from the University of South Florida:

What a submerged ancient bridge discovered in a Spanish cave reveals about early human settlement

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A new study led by the University of South Florida has shed light on the human colonization of the western Mediterranean, revealing that humans settled there much earlier than previously believed. This research, detailed in a recent issue of the journal, Communications Earth & Environment, challenges long-held assumptions and narrows the gap between the settlement timelines of islands throughout the Mediterranean region.

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Reconstructing early human colonization on Mediterranean islands is challenging due to limited archaeological evidence. By studying a 25-foot submerged bridge, an interdisciplinary research team – led by USF geology Professor Bogdan Onac – was able to provide compelling evidence of earlier human activity inside Genovesa Cave, located in the Spanish island of Mallorca.

The presence of this submerged bridge and other artifacts indicates a sophisticated level of activity, implying that early settlers recognized the cave's water resources and strategically built infrastructure to navigate it.

Professor Bogdan P. Onac, Lead author
Karst Research Group
School of Geosciences
University of South Florida, Tampa, FL, USA.

The cave, located near Mallorca’s coast, has passages now flooded due to rising sea levels, with distinct calcite encrustations forming during periods of high sea level. These formations, along with a light-colored band on the submerged bridge, serve as proxies for precisely tracking historical sea-level changes and dating the bridge's construction.

Mallorca, despite being the sixth largest island in the Mediterranean, was among the last to be colonized. Previous research suggested human presence as far back as 9,000 years, but inconsistencies and poor preservation of the radiocarbon dated material, such as nearby bones and pottery, led to doubts about these findings. Newer studies have used charcoal, ash and bones found on the island to create a timeline of human settlement about 4,400 years ago. This aligns the timeline of human presence with significant environmental events, such as the extinction of the goat-antelope genus Myotragus balearicus.

By analyzing overgrowths of minerals on the bridge and the elevation of a coloration band on the bridge, Onac and the team discovered the bridge was constructed nearly 6,000 years ago, more than two-thousand years older than the previous estimation – narrowing the timeline gap between eastern and western Mediterranean settlements.

This research underscores the importance of interdisciplinary collaboration in uncovering historical truths and advancing our understanding of human history.

Professor Bogdan P. Onac.

This study was supported by several National Science Foundation grants and involved extensive fieldwork, including underwater exploration and precise dating techniques. Onac will continue exploring cave systems, some of which have deposits that formed millions of years ago, so he can identify preindustrial sea levels and examine the impact of modern greenhouse warming on sea-level rise.

This research was done in collaboration with Harvard University, the University of New Mexico and the University of Balearic Islands.

Abstract
Reconstructing early human colonization of the Balearic Islands in the western Mediterranean is challenging due to limited archaeological evidence. Current understanding places human arrival ~4400 years ago. Here, U-series data from phreatic overgrowth on speleothems are combined with the discovery of a submerged bridge in Genovesa Cave that exhibits a distinctive coloration band near its top. The band is at the same depth as the phreatic overgrowth on speleothems (−1.1 meters), both of which indicate a sea-level stillstand between ~6000 and ~5400 years ago. Integrating the bridge depth with a high-resolution Holocene sea-level curve for Mallorca and the dated phreatic overgrowth on speleothems level constrains the construction of the bridge between ~6000 and ~5600 years ago. Subsequent sea-level rise flooded the archeological structure, ruling out later construction dates. This provides evidence for early human presence on the island dating at least 5600 and possibly beyond ~6000 years ago.

Introduction
Mallorca, the main island of the Balearic Archipelago, is the sixth largest in the Mediterranean Sea, yet it was among the last to be colonized¹. An in-depth discussion concerning the earliest colonization of various Mediterranean islands, including Mallorca, may be found in Cherry and Leppard1, Dawson², and Simmons³. Despite extensive research on this topic, there has been considerable disagreement about the timing of the earliest colonization of Mallorca. Radiocarbon dating of bone material excavated from Cova (Cave) de Moleta indicate human presence on the island as early as 7000 calibrated years before present (cal B.P.)⁴. Subsequent age determinations from findings in Cova de Canet, further extended the timeline, suggesting human occupation dating back to approximately 9000 cal B.P.⁵. A series of publications^{6,7,8,9,10,11} revealed inconsistencies regarding the exact stratigraphic position and context of the dated bone (sample KBN-640d12) in Cova de Moleta. Due to the overall poor preservation of the samples and the lack of clear and specific information on this particular radiocarbon-dated sample, Ramis and Alcover⁷ suggested that the bone fragment, initially identified as human, might actually belong to M. balearicus, an endemic bovid. Consequently, this sample was considered not relevant for determining the timing of the island’s colonization. Similarly, the radiocarbon dates from Cova de Canet were considered highly controversial because they originate from a charcoal layer that lacks clear evidence of human activity^7,8. Furthermore, in neither of these caves do the M. balearicus bones show butchery marks, making it difficult to establish a clear link to contemporary human presence2. Due to the aforementioned issues these early results were deemed unreliable^1,8,13.

Several studies have reevaluated most of the previously dated materials and supplemented them with new radiocarbon dates obtained from charcoal, ash, and bones^6,7,9,10. Based on these new results, there is now a consensus that the timeframe for earliest human settlement on the island is between 4600 and 4200 cal B.P.¹⁴.

Dawson2 presents a synthesis of the various lines of argument regarding arrival models in the Balearic islands that includes: (1) Early (~9000 cal B.P.), (2) Intermediate (~7600 cal B.P.), and (3) Late (~5000 cal B.P.) arrival phases. The last two models suggest the existence of stable settlements, yet only the third one has been deemed plausible in the local archeological literature^7,8,14.

While there has been a growing body of evidence revealing progressively earlier human settlements on many islands in the Mediterranean basin, the timeline for the initial human colonization in Mallorca has seen relatively minor adjustments over the past decades^8,15,16. The latest research suggests that this colonization occurred approximately 4400 cal B.P., coinciding with the human-mediated extinction of Myotragus balearicus¹⁴. This conclusion is based on two radiocarbon ages, which provide a relatively narrow time window of 350 years (p > 90%) between the last documented Myotragus bone (4581–4417 cal B.P.) and the first dated sheep bone (4417–4231 cal B.P.). However, it remains challenging to confirm whether the ages of these paleontological remains represent the latest or the earliest such occurrences on the island. Subsequent field work may shed light on this matter.

Our study site is a submerged archeological structure in the Genovesa Cave (also known as Cova de’n Bessó; 39°31’32” N, 3°19’2” E), situated in the eastern part of Mallorca (Fig. 1a, b). The cave hosts ceramic sherds and stone constructions. The latter includes a stone-paved path that connects the cave entrance to the first underground lake (Fig. 1d), a cyclopean stone wall running parallel to the path, and an 8.62 m long¹⁷ and 0.5 m high stone walkway (hereafter referred as to bridge) oriented NE–SW (Fig. 1c, e, Supplementary Fig. 1, Supplementary Table 1). This last structure was built across a lake by stacking large limestone breakdown blocks on top of each other, without the use of mortar or cement. The uppermost layer comprises flat boulders of considerable size (Supplementary Fig. 1b). The largest stone measures 1.63 m in length and 0.6 m in width. Relative to the preindustrial (pre-1900 CE) sea level, the bridge is submerged by 1.05 ± 0.1 m of water at its upper part (Figs. 1e, 2). However, at the time of its construction, it served as an access path to the only other dry chamber in the cave (Sala de les Rates-pinyades, i.e., Bats Room), where pottery, tentatively attributed to the Naviform period (ca. 3550–3000 cal B.P.) was discovered^18,19. The bridge structure was inferred to have been built around the same period²⁰.

Fig. 1: Cave and sample locations.

a Map showing Mallorca in the western Mediterranean (black square). b Location of Genovesa and Drac caves; CCG: Closos de Can Gaià archeological site. c Plan of Genovesa Cave showing the location of the phreatic overgrowth on speleothems samples (yellow circles) and the survey station (red dot). d Photograph of the stone-paved path leading to the bridge (person height = 167 cm). e Cross-section (x–x’) indicating the location of the submerged bridge relative to the cave entrance and the present sea level. Maps (a, b) are available under CC Public Domain License from https://pixabay.com/illustrations/map-europe-world-earth-continent-2672639/ and https://pixabay.com/illustrations/mallorca-map-land-country-europe-968363/, respectively.

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Fig. 2: Positional relationship between the bridge, preindustrial sea level, and analyzed samples.

The cross sections depict the spatial relationship between the submerged bridge and the U-series dated samples (phreatic overgrowth on speleothems: orange/yellow spindle; soda straw tips: red circle) from Genovesa and Drac caves. The vertical scale applies uniformly to all samples from both caves. All ages are reported as thousands of years (kyr) before present, where present is defined as 1950 CE.

Here, we integrate uranium-series (U-series) age data acquired from phreatic overgrowth on speleothems and stalactite tips in Genovesa and Drac caves, along with Late Holocene relative sea level (RSL) information available for Mallorca²¹. Additionally, we consider the presence of the bridge, the coloration mark on its upper part, and the depths at which these respective features occur. This combined evidence contributes valuable insights to the ongoing debate surrounding the timing of human colonization on Mallorca.

Because Creationists love to find fault with the geochronology in these records of pre-'Creation Week' events, I've included sections on geochronology here:

Results and discussion
Speleothems and sea level
Proxies for cave-based sea-level reconstructions include mineralogical (sediments, speleothems)^22,23, archeological (fish tanks, saltpans, submerged structures, etc.)²⁴, and biological (borings, worm tubes, etc.)²⁴ records. In the case of Genovesa Cave, a typical coastal karst feature situated <450 m from the shoreline, both mineralogical and archeological records are present. Many of its well-decorated passages, galleries, and chambers are now flooded due to rising sea levels²⁰. Because of the cave’s proximity to the coast and the high permeability of the Upper Miocene host rock²⁵, the hydraulic gradient is negligible (9 × 10^-5 m /m) for such short distances (see Methods), and thus the water table in the cave is, and was in the past, coincident with sea ^26,27. During times of high sea level stillstands, when the cave was partly flooded, distinct encrustations of calcite and aragonite accumulated over preexisting stalactites, forming the so-called phreatic overgrowths on speleothems²⁸ (POS). This is a particularly useful proxy for precisely and accurately reconstructing sea-level changes across various timescales^21,29. Furthermore, ordinary stalactites, which form in cave passages above the water table and later become submerged as sea-levels rise are also valuable in this process since they document the moment when the cave shifted from being air- to water-filled²².

A distinct light-colored band (~15 cm wide) is visible along the entire bridge at its upper part (Fig. 2, Supplementary Fig. 1a). This coloration mark bears a resemblance to a “bathtub ring” and its presence is likely related to a relatively short-lived stable water table that allowed the precipitation of a sub-millimeter calcite crust at the water/air interface. When the water level increased, the calcite did not disappear since the water below the water table remained somewhat saturated with respect to calcium carbonate. As discussed later, this feature along with the new POS ages and their elevation play a crucial role in determining when this bridge, now submerged, was constructed.

Geochronology
The U-series ages (n = 34; 28 for POS and 6 from stalactites) are given in Supplementary Table 2 and are all reported as years before present (BP), where present is 1950 CE. Ten of these ages are from POS samples GE-D8 (Genovesa Cave; Supplementary Fig. 2) and DR-D15 dated as part of a prior study²¹. The latter was collected in Drac Cave (39°32’9” N, 3°19’49” E), located 1.6 km to the north-east of Genovesa Cave (Fig. 1c, Supplementary Figs. S3–S4).

Regardless of the sampling depth, all the vadose stalactites on which the POS formed in both caves, produced ages older than 8200 years B.P. (Fig. 2, Supplementary Fig. 5). The phreatic overgrowth samples GE-D6, GE-D7, and DR-D23 (Supplementary Figs. S6–S8), precipitated at ~1.10 ± 0.1 m below the preindustrial sea level (mbpsl). A ²³²Th/²³⁸U-²³⁴U/²³⁸U-²³⁰Th/²³⁸U (plotted as a Rosholt A type) isochron age of 5479 ± 120 years B.P. (n = 3 of 4; hereafter, ± refers to 2 σ uncertainty) was measured for GE-D6 (Supplemental Table 2, Supplementary Fig. 9a). GE-D7, in the same room and at the same elevation as GE-D6, yielded a weighted average age of 5510 ± 549 years B.P. using the same correction (initial ²³⁰Th/²³²Th atomic ratio = 5.1 ± 0.4 ppm) generated by the GE-D6 isochron age. Onac et al.²¹. used a slightly higher initial for GE-D8 (8 ppm) that was located at a higher elevation than GE-D6 & -D7. For DR-D23, we obtained a ²³²Th/²³⁸U-²³⁴U/²³⁸U-²³⁰Th/²³⁸U (plotted as a Rosholt A type) isochron age of 5824 ± 140 years B.P. (n = 6) (Supplementary Table 2, Supplementary Fig. 9b). This isochron shows an exceptionally high initial ²³⁰Th/²³²Th atomic ratio = 527.5 ± 22.1 ppm, more than 10x higher than used for DR-D15 (44 ppm) from the same cave but at a different elevation²¹. The fluffy fibrous cotton-candy texture of the two sub-samples with high U component of DR-D23 may have something to do with the high initial ²³⁰Th/²³²Th. The isochron ages were necessary to produce accurate ages with smaller uncertainties.

Collectively, the POS data from Genovesa and the nearby Drac, reveal three distinct periods of relative sea-level stability (Fig. 2). One occurred at 0 ± 0.04 m from 2720 ± 11 to 296 ± 18 years B.P. The second period lasting from 3703 ± 14 to 3368 ± 8 years B.P., corresponds to a sea level of 0.25 mbpsl. Lastly, a third period at ~1.1 ± 0.1 mbpsl is documented between 5820 ± 140 and 5479 ± 120 years B.P. (Figs. 2, 3). By adding the uncertainty to the older age and subtracting the uncertainty from the younger age, the maximum time span of POS growth at 1.1 mbpsl ranges from 5964 – 5359 years B.P. During this interval, both the POS and the coloration mark formed. For the latter to develop, the bridge must have been submerged, at least to its upper surface, allowing calcite to precipitate during the sea-level stillstand. Therefore, this period is of particular interest because it may aid in providing the timeline of the bridge construction as detailed below.

Timing of bridge construction
The assembly date of the bridge in Genovesa Cave remains uncertain due to the absence of written records or a robust time-stratigraphic context. In order to constrain the building time of this archeological structure, we rely on a well-defined Late Holocene sea-level curve generated by Onac et al.²¹. for Mallorca (depicted by the solid blue line in Fig. 3) and the ages and depths at which POS grew and coloration mark formed. First, we assess previous assumptions regarding the timing of the submerged bridge construction using this curve. Then, we examine our new sea-level data in conjunction with the timing of the earliest human arrival model proposed by Bover et al.¹⁴.

The prehistoric pottery discovered in Sala de les Rates-pinyades of the Genovesa Cave has been linked to the Naviform period (3550–3000 cal B.P.). This attribution is based on typological similarities between the ceramics found in Genovesa and those documented at the Closos de Can Gaià, a Bronze Age site located ~10 km south of our cave (Fig. 1b). The archeological horizon in which comparable pottery was discovered at the latter site was dated to ~3600 cal B.P30. However, Costa and Guerrero31 argue that Closos de Can Gaià excavation required a reassessment of the chronological framework, due to issues with the radiocarbon dates. Despite this, adopting the previously reported radiocarbon age, Gràcia et al.²⁰ suggested that the construction of the bridge likely occurred toward the end of the Naviform period.

However, the RSL curve (Fig. 3) indicates that sea level was ~0.25 ± 0.1 m below the preindustrial baseline ~3500 years ago²¹, implying a total water depth of ~1.3 m in the cave lake. The vertical height of the bridge is 0.5 m, and thus it was submerged by 0.8 m of water at this time (Fig. 3). The construction of the bridge around 4400 years ago, the time suggested by Bover et al.¹⁴ to be the earliest evidence of human presence on the island, is also improbable. At that time, relative sea level in Mallorca was ~0.35 ± 0.1 m below preindustrial level, and the bridge would have been submerged by 0.7 m. Building a bridge below water level is a highly unlikely scenario, and thus it was likely built at an earlier time, when sea level was lower. The predicted relative sea-level curve for Mallorca (Fig. 3) indicates that the top of the bridge would have been close to water level no earlier than 5600 years ago and this provides an approximate lower bound on the age of the feature. The distinct coloration mark on the bridge also provides strong evidence of an age greater than the ages estimated by Gràcia et al.²⁰ and Bover et al.¹⁴. As discussed earlier and according to the POS-based relative sea-level record, this mark would not have developed if the top of the bridge was well below the water level, i.e., at times more recent than ~5500 years ago. However, an age older than 6000 years for the feature can be ruled out since sea level was even lower (Fig. 3), and the construction of a bridge at its current height would have been unnecessary.

Fig. 3: Proposed timing for bridge construction.

Comparison between the position of the submerged bridge, phreatic overgrowth on speleothems (POS), coloration mark, and the RSL prediction (blue curve)²¹ based on a Glacial Isostatic Adjustment model that uses the ICE-6G (VM 5) ice history with an upper mantle viscosity of 1.3 × 1020 Pa s. Solid symbols with age and depth uncertainties represent POS elevations. The brown rectangle depicts the bridge with its coloration band in the upper part. The insets show an underwater image of the bridge (Photo courtesy of R. Landreth) and a close-up view on the RSL position of samples GE-D6, GE-D7, and DR-D23 that grew at 1.1 mbpsl. The uncertainties for GE-D6, GE-D7, and DR-D23 are absolute 2 σ error bars based on three dimensional isochron ages or weighted average (GE-D7). The dotted blue line is a sea-level rise scenario that includes the brief stillstand inferred from the POS growth.

The phreatic overgrowths GE-D6, GE-D7, and DR-D23 from Genovesa and Drac caves formed at a relative sea level of 1.1 mbpsl, which is 5 cm below the upper part of the bridge. The two more precise isochron ages suggest sea-level remained relatively constant for a few hundreds of years between ~5964 and 5359 years B.P. The relative brevity of this time frame might explain why the morphology and size of the POS are somehow atypical and smaller compared to those POS that developed when the sea level was stable at 0 m for over 2000 years. Furthermore, this <600 year period of nearly constant sea level was sufficient to develop the coloration mark. Given that the occurrence of this feature correlates directly with the previously mentioned sea-level stillstand position, it suggests that the bridge was already in place. In fact, its construction could have commenced as early as ~6000 years ago when the water depth in the lake was ~0.25 m. However, it had to be completed before ~5600 years ago when the sea-level rose to the top surface of the bridge.

Onac, B.P., Polyak, V.J., Mitrovica, J.X. et al.
Submerged bridge constructed at least 5600 years ago indicates early human arrival in Mallorca, Spain. Commun Earth Environ 5, 457 (2024). https://doi.org/10.1038/s43247-024-01584-4

Copyright: © 2024 The authors.
Published by Springer Nature Ltd. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

Lots of stuff for creationists to lie about there. Firstly, there is the record of sea-level changes reflecting the advance and retreat of ice sheets over the past few tens of thousands of years.

Then there is the record of human habitation and construction of the bridge when creationist mythology says the world was subject to a genocidal flood in which all life was extinguished save a small handful of survivors that then repopulated the planet in just a few thousand years.

What a creationist now needs to do is explain why all the dating methods, which converge on these dates, are all wrong and should be converging on a much more recent date compatible with creation of Earth from nothing just 10,000 years ago and all human life originating from 8 related individuals just 4,000 years ago.

Sadly, because the authors of these myths knew nothing of the real history of the Western Mediterranean, the book they wrote, and which creationists think is a real history book, is entirely silent on the matter.