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:
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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:
- 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.
- 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.
- 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.
- 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.
- 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.
- 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
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.
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:
- 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].
- 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:
- 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.
- 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
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
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.
