What are the main types of algae and how do they differ? Algae are classified into several main groups based on their characteristics, including pigmentation, cellular structure, and mode of reproduction. The main types of algae include:Today’s refutation of creationists dogma comes in the form of an open access paper just published in the Cell Press journal, Molecular Plant. Research biologists have revealed how multicellularity evolved several times independently in algae, and how many of the new genes were acquired initially by viruses.These main types of algae differ in their pigmentation, cellular structure, habitat preferences, and ecological roles. While some are beneficial and essential for ecosystem health, others can become problematic under certain conditions, such as nutrient pollution or climate change. Understanding the characteristics and ecological functions of different types of algae is crucial for managing and conserving aquatic ecosystems.
- Diatoms (Bacillariophyta):
- Diatoms are single-celled algae characterized by their unique glass-like silica cell walls called frustules.
- They are typically found in freshwater and marine environments.
- Diatoms are important primary producers and play a significant role in the global carbon cycle.
- Green Algae (Chlorophyta):
- Green algae encompass a diverse group of algae that are mostly freshwater but also found in marine and terrestrial environments.
- They contain chlorophyll a and b, giving them a green color, similar to land plants.
- Green algae can be unicellular, colonial, filamentous, or multicellular, with a wide range of morphologies.
- Red Algae (Rhodophyta):
- Red algae are predominantly marine algae, although some species can also be found in freshwater.
- They contain pigments like chlorophyll a and various accessory pigments, including phycobiliproteins, giving them shades of red, pink, or purple.
- Red algae often have complex multicellular structures and are important contributors to coral reef ecosystems.
- Brown Algae (Phaeophyta):
- Brown algae are primarily marine algae, commonly found in cold-water habitats.
- They contain chlorophyll a and c, along with fucoxanthin, which gives them their characteristic brown color.
- Brown algae can range from small filamentous forms to large, complex seaweeds like kelps.
- Blue-Green Algae (Cyanobacteria or Cyanophyta):
- Despite being called algae, cyanobacteria are actually prokaryotic organisms, classified within the domain Bacteria.
- They are photosynthetic and often form colonies or filaments.
- Cyanobacteria can be found in diverse habitats, including freshwater, marine environments, soil, and even extreme environments like hot springs.
- Some cyanobacteria can produce toxins under certain conditions, leading to harmful algal blooms (HABs) and posing risks to aquatic life and human health.
This gives the lie to creationist claims that new information can't arise in the genome because of some half-baked confusion of information with energy and a nonsensical assumption that new genetic information would need to come from nothing.
And of course, like about 99.99% of the history of life on Earth, it all happened in that very long period of pre-'Creation Week' history between Earth forming in an accretion disc around the sun and creationism's little god creating a small flat planet with a dome over it in the Middle East out of nothing, according to creationist mythology
In information provided by Cell Press ahead of publication, the scientists at New York Abu Dhabi University and Technology Innovation Institute, United Arab Emirates, said:
A deep dive into macroalgae genetics has uncovered the genetic underpinnings that enabled macroalgae, or "seaweed," to evolve multicellularity. Three lineages of macroalgae developed multicellularity independently and during very different time periods by acquiring genes that enable cell adhesion, extracellular matrix formation, and cell differentiation, researchers report April 12 in the journal Molecular Plant. Surprisingly, many of these multicellular-enabling genes had viral origins. The study, which increased the total number of sequenced macroalgal genomes from 14 to 124, is the first to investigate macroalgal evolution through the lens of genomics.
Macroalgae live in both fresh and seawater and are complex multicellular organisms with distinct organs and tissues, in contrast to microalgae, which are microscopic and unicellular.This is a big genomic resource that will open the door for many more studies. Macroalgae play an important role in global climate regulation and ecosystems, and they have numerous commercial and ecoengineering applications, but until now, there wasn't a lot of information about their genomes.
Alexandra Mystikou, co-first author
Division of Science and Math
New York University Abu Dhabi, Abu Dhabi, UAE.
There are three main groups of macroalgae -- red (Rhodophyta), green (Chlorophyta), and brown (Ochrophyta) -- that independently evolved multicellularity at very different times and in very different environmental conditions.
Rhodophytes and Chlorophytes both evolved multicellularity over a billion years ago, while Ochrophytes only became multicellular in the past 200,000 years.
To investigate the evolution of macroalgal multicellularity, the researchers sequenced 110 new macroalgal genomes from 105 different species originating from fresh and saltwater habitats in diverse geographies and climates.
The researchers identified several metabolic pathways that distinguish macroalgae from microalgae, some of which may be responsible for the success of invasive macroalgal species.
Many of these metabolic genes appear to have been donated by algae-infecting viruses, and genes with a viral origin were especially prevalent in the more recently evolved brown algae.
They found that macroalgae acquired many new genes that are not present in microalgae on their road to multicellularity.
For all three lineages, key acquisitions included genes involved in cell adhesion (which enables cells to stick together), cell differentiation (which allows different cells to develop specialized functions), cell communication, and inter-cellular transport.
The team also identified other features that were distinct between the macroalgal lineages.Many brown algal genes associated with multicellular functions had signature motifs that were only otherwise present in the viruses that infect them. It's kind of a wild theory that's only been hinted at in the past, but from our data it looks like these horizontally transferred genes were critical factors for evolving multicellularity in the brown algae.
David Nelson, co-first author
Division of Science and Math
New York University Abu Dhabi, Abu Dhabi, UAE.
They observed much more diversity between different species of Rhodophyte, which evolved multicellularity first and have thus had longer to diverge.
They also found that Chlorophytes share many genomic features with land plants, suggesting that these genes may have already been present in the last common ancestor of Chlorophytes and plants.
The researchers are already digging into the dataset to investigate environmental and habitat adaptations amongst macroalgae.By no means have we exhaustively explored all that there is in these genomes. There is a ton of information that we have not touched in the present paper that can be mined by whoever who is interested. We want to explore some of these features in more detail, meaning more genomes if we can get our hands on them.
Kourosh Salehi-Ashtiani, senior author.
Division of Science and Math
New York University Abu Dhabi, Abu Dhabi, UAE.
In future, they hope to sequence and analyze even more macroalgal genomes.
AbstractIn summary, there are unmistakable genetic signals of the evolution of multicellularity by three different pathways that converge on a single solution. No intelligent designer would invent three different ways of achieving the same thing, so what creationists normally claim as evidence of a common designer is denied to them, whereas the Theory of Evolution which says that organisms tend towards greater fitness in their environment predicts convergence from different starting points in the same or similar environments.
Macroalgae are multicellular, aquatic autotrophs that play vital roles in global climate maintenance and have diverse applications in biotechnology and eco-engineering, which are directly linked to their multicellularity phenotypes. However, their genomic diversity and the evolutionary mechanisms underlying multicellularity in these organisms remain uncharacterized. In this study, we sequenced 110 macroalgal genomes from diverse climates and phyla, and identified key genomic features that distinguish them from their microalgal relatives. Genes for cell adhesion, extracellular matrix formation, cell polarity, transport, and cell differentiation distinguish macroalgae from microalgae across all three major phyla, constituting conserved and unique gene sets supporting multicellular processes. Adhesome genes show phylum- and climate-specific expansions that may facilitate niche adaptation. Collectively, our study reveals genetic determinants of convergent and divergent evolutionary trajectories that have shaped morphological diversity in macroalgae and provides genome-wide frameworks to understand photosynthetic multicellular evolution in aquatic environments.
Introduction
Macroalgae encompass a diverse array of organisms belonging to three distinct phyla, each of which has independently evolved multicellularity. These organisms demonstrate extraordinary morphological diversity, ranging from millimeter-scale filaments to colossal 65-m-long kelps, and inhabit a variety of ecological niches. The simpler form of multicellularity, filamentous growth, is common in macroalgae and parallels that seen in other simpler multicellular phototroph lineages, such as Zygnematophyceae (Hess et al., 2022). While many algal lineages have adopted simple multicellularity, complex phototrophic multicellularity is a defining feature of plants and macroalgae (Adl et al., 2012). Shifts to simpler multicellularity from unicellularity (e.g., in Volvox carterii) (Prochnik et al., 2010) may not show significant changes in gene content, instead resulting primarily from differential regulation of gene expression (Matt and Umen, 2018) and splicing patterns (Balasubramanian et al., 2023). Indeed, shifts to multicellularity can be observed experimentally with little or no change in basal genetic content (Ratcliff et al., 2012.1), and some lineages have reverted to unicellular forms after evolutionary periods of multicellularity. Thus, transitions to complex multicellularity are more likely to involve newly acquired, lineage-defining gene sets, which can be discovered through extensive genome sequencing.
The three principal phyla (Adl et al., 2019) of marine macroalgae—Rhodophyta (Brawley et al., 2017) (red algae), Chlorophyta (He et al., 2021) (green algae), and Ochrophyta (Bringloe et al., 2020) (brown algae)—exemplify the convergent evolution of complex multicellularity in aquatic phototrophs. Studies on Volvox carteri, a simple multicellular green alga, shed light on the early stages of chlorophyte germ-soma differentiation, a key feature of multicellularity (Ferris et al., 2010.1; Prochnik et al., 2010; Matt and Umen, 2016, Matt and Umen, 2018; Umen, 2020.1; Yamamoto et al., 2021.1; Balasubramanian et al., 2023). The comprehensive analysis of Volvox cell-type transcriptomes revealed distinct molecular and metabolic programming between these cell types (Matt and Umen, 2018). Nonetheless, while regulatory changes play a key role in the evolution of multicellularity in the volvocine green algae, no significant changes in gene content were found compared to its closest unicellular relatives. While increased sophistication in ECMs are hallmarks of many simple multicellular lineages, their higher complexity usually derives from gene regulatory changes and not acquisitions (Kloareg et al., 2021.2).
Macroalgal lineages evolved specific metabolic and morphological traits underlying their multicellular phenotypes, which form independent bases for their evolution of multicellularity. Investigating the genetic foundations of multicellularity in these lineages is crucial for understanding how complex life adapts to varying environmental challenges and for gaining insights into the genetic underpinnings of this significant evolutionary transition. A scarcity of macroalgal genome sequences has thus far constrained the development of a comprehensive comparative analysis of macroalgal multicellularity. Increased genome sample sizes will facilitate the statistical resolution of hypothesis tests regarding phyla-wide gene gains and losses accompanying the rise to multicellularity in the three clades. In this study, we greatly expanded the number of available macroalgal genomes from 14 to 124, shedding new light on the genomic basis of macroalgal multicellularity.
Rhodophyta and Chlorophyta algae belong to the Archaeplastida supergroup descending from the original plastid/nuclear symbiotic event in eukaryotic algae (Yoon et al., 2004; Brawley et al., 2017). In contrast, Ochrophyta contain Rhodophyta algal plastids derived from further endosymbiosis (Bringloe et al., 2020). Ochrophyta evolution through this route may have involved multiple secondary endosymbioses, rather than a single event (Yoon et al., 2004). Macroalgae thrive in various conditions in all climates in marine, freshwater, and brackish environments. They can grow in intertidal and benthic regions as deep as 268 m (Littler et al., 1985). They represent a particularly powerful system for examining the environmental and genetic drivers of multicellular evolution, as independent transitions in these clades were separated by more than a billion years and occurred under fundamentally different environmental conditions (Yoon et al., 2004; Brawley et al., 2017).
The evolution of algal lineages has been meticulously analyzed using molecular clock experiments and geological evidence (Heckman et al., 2001; Douzery et al., 2004.1; Hedges et al., 2004.2; Yoon et al., 2004; Berney and Pawlowski, 2006; Zimmer et al., 2007; Herron et al., 2009; Lang et al., 2010.2; Fiz-Palacios et al., 2011; Gueidan et al., 2011.1; Parfrey et al., 2011.2; Blank, 2013; Gaya et al., 2015; Munakata et al., 2016.1; Yang et al., 2016.2; Caspermeyer, 2017.1). Ochrophyta and Rhodophyta diverged ∼1.6 billion years ago (bya), and rhodophytes and chlorophytes split ∼1.2 bya. Chlorophyta and rhodophyte macroalgae emerged more than 1 bya; in contrast, the stramenopile-origin macroalgal Phaeophyceae only emerged ∼200 million years ago (mya) (Supplemental Figure 1). Phaeophyte seaweeds thus evolved in a period with comparably high atmospheric O2 and solar luminosity but low CO2 (Supplemental Figure 1). The global prevalence of the recently emerged Phaeophyceae, evident in extensive giant kelp forests and abundant seaweed biomass, indicates they are well adapted to thrive in contemporary environmental conditions. For instance, Sargassum emerged only 6.7 mya (Yip et al., 2020.2), yet has swiftly colonized the world’s oceans, generating significant biomass (Arellano-Verdejo and Lazcano-Hernandez, 2021.3; Liu et al., 2021.4; Song et al., 2021.5; Stelling-Wood et al., 2021.6; Mulders et al., 2022.1). Invasive phaeophytes threaten various industries and ecosystems; understanding the genomic and evolutionary bases of their success will facilitate management efforts and biotechnological utilization (Charrier et al., 2017.2).
Our large-scale project, ALG-ALL-CODE-macro, sequenced 110 macroalgal genomes from diverse climates and phyla, offering new insights into macroalgal biology and the evolution of multicellularity. We identified key genes for processes necessary for multicellular phenotypes (e.g., cellular adhesion, transcription factors [TFs]). Many of these had viral origins and were unique to or conserved among the three primary three macroalgal lineages. The diverse viral-origin sequences in various proteins underpin lineage-specific mechanisms that support the evolution of multicellular macroalgae with differentiated, coordinated tissues. Our study illuminates the convergent and divergent evolutionary trajectories shaping macroalgae’s diverse morphologies, outlining a basis for understanding photosynthetic multicellular evolution in marine environments.
Then there are the genetic signals of insertions of viral DNA or transcriptions of viral RNA into the evolving genomes, exapted where necessary to play a part in this evolutionary process.
And it all took place over tens or hundreds of millions of years in the pre-'Creation Week' history of life on Earth, with the newest being a mere 190,000 years before 'Creation Week'.
Just the latest confirmation of the TOE and a refutation of basic creationist dogmas by scientists. And the latest piece of research for creationist frauds to put their thinking caps on and come up with some lies and/or misrepresentations with which to fool their cult members and keep the cash flow running.
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