Creationism in Crisis - Scientists Use Algae to Work Out How Plants Evolved in 600 Million Years

Microscope image of one of the closest algal relatives of land plants, a single-celled alga called Mesotaenium endlicherianum (20 micrometres corresponds to 0.02 millimetres)

Photo: Tatyana Darienko

Mesotaenium endlicherianum
Closest to the first algae to colonize the land

Press release: Algae provide clues about 600 million years of plant evolution

No doubt to the discomfort of creationists, a team of researchers led by Professor Jan de Vries of the University of Göttingen, Germany, have worked out how terrestrial plants have evolved in the 600 million years since the first marine algae colonize the land. This colonization is believed to have occurred just once, so all terrestrial plants are descended from that single colonizing species.

Note the question was not whether, but how this evolutionary process occurred. There was never a shadow of doubt that it was an evolutionary process in which there was no evidence of magic or supernatural interference with chemistry and physics.

Using the results of a series of experiments that have been running in the research lab in Gottingen for over 25 years, the team were able to identify key evolutionary changes that occurred as a prequel to land colonization and which are still to be found in terrestrial plants after 600 million years of evolutionary diversification.

Creationists must now draw on their repertoire of rehearsed dismissals of the science to cope with these finding and maintain the myth that land plants were created as is in one day about 8000 years ago, and have not evolved since:

• Redefine evolution ("They're still plants!").
• The dates are wrong ("Radiometric dating is flawed; it wasn’t hundreds of millions; it was just hundreds of years!").
• The scientists are lying ("It's a Satanic conspiracy to turn people away from Jesus!")

First a little AI background on marine algae and when the transition to terrestrial living occurred:

For how long were there marine algae before they colonized the land?

Marine algae, also known as seaweeds, are a diverse group of photosynthetic organisms that inhabit marine environments. The exact timing of when marine algae first evolved and when they transitioned to terrestrial colonization is challenging to determine precisely due to the limitations of the fossil record and the complex nature of evolutionary processes. However, based on available scientific evidence, marine algae likely existed in aquatic environments for billions of years before the first land colonization events occurred.

The earliest evidence of life on Earth dates back to around 3.5 to 3.8 billion years ago, in the form of simple single-celled organisms. These early life forms were likely aquatic and inhabited the oceans. Over time, a wide range of aquatic life forms evolved, including various types of algae.

The first land plants are believed to have emerged from aquatic ancestors, likely green algae, sometime around 500 to 600 million years ago during the Late Cambrian or Early Ordovician periods. These early plants were relatively simple and lacked many of the adaptations necessary for life on land. They gradually developed the features needed to cope with terrestrial environments, such as cuticles to prevent water loss and mechanisms for reproduction and dispersal.

It's important to note that while the first terrestrial plants were evolving, marine algae continued to thrive in aquatic habitats. Marine algae have a long and complex evolutionary history that predates the emergence of land plants. They played a crucial role in shaping marine ecosystems and contributed to the Earth's oxygen-rich atmosphere through photosynthesis.

In summary, marine algae likely existed in aquatic environments for billions of years before the colonization of land by plants. The transition from aquatic to terrestrial habitats was a gradual process that took place over hundreds of millions of years and involved a series of adaptations that allowed plants to conquer new ecological niches.

How long did it take marine algae evolve to the stage where terrestrial colonization was possible?

The transition from marine algae to the stage where terrestrial colonization was possible occurred over an immensely long period of time, spanning hundreds of millions of years. The exact duration is challenging to pinpoint precisely due to gaps in the fossil record and the complexity of the evolutionary processes involved. However, researchers estimate that this transition took place over the course of roughly 100 to 200 million years.

The first plants to venture onto land were likely simple non-vascular plants, such as liverworts and mosses, which lacked many of the adaptations necessary for life on land as we know it today. These early land plants would have faced numerous challenges in adapting to terrestrial environments, such as desiccation (drying out), the absence of a supportive medium, and the need to develop reproductive mechanisms suited to land.

The development of vascular tissues (xylem and phloem) in plants marked a significant milestone in the colonization of land. Vascular tissues allowed for more efficient transport of water, nutrients, and sugars within the plant's structure. This innovation enabled plants to grow larger and more complex, paving the way for further adaptations.

The evolution of seeds and the subsequent rise of seed plants (gymnosperms and angiosperms) were critical steps in the colonization of land. Seeds provided protection for the developing embryo and allowed for more effective dispersal, which were essential for plants to thrive in various terrestrial environments.

Overall, the transition from marine algae to fully terrestrial plants involved a series of incremental adaptations and innovations that occurred over hundreds of millions of years. This process highlights the remarkable capacity of life to adapt to new environments and niches over geological timescales.

Tell me all about terrestrial plant evolution from marine algae.

The evolution of terrestrial plants from marine algae is a fascinating story that spans millions of years and involves numerous adaptations that allowed plants to colonize and thrive in terrestrial environments. This transition marked a significant milestone in the history of life on Earth and led to the development of the diverse array of plant species we see today.

Here's an overview of the key stages and adaptations involved in the evolution of terrestrial plants from marine algae:

1. Colonization of Land (Non-Vascular Plants): The first plants to transition from marine environments to land were non-vascular plants, which include liverworts, mosses, and hornworts. These plants lack vascular tissues like xylem and phloem, which are crucial for transporting water, nutrients, and sugars in larger land plants. To survive on land, they developed adaptations such as cuticles (waxy coatings) to reduce water loss and specialized structures for reproduction, such as sporangia that released spores for dispersal.
2. Vascular Tissues and Roots (Vascular Plants): Vascular plants, which include ferns, horsetails, and clubmosses, evolved vascular tissues that enabled them to grow larger and more complex. Xylem allowed for efficient water and mineral transport from the roots to the rest of the plant, while phloem facilitated the movement of sugars produced through photosynthesis. This innovation allowed plants to explore drier habitats and to grow taller.
3. Seed Development (Seed Plants): The evolution of seeds was a crucial step in adapting to life on land. Seeds provide protection for the developing embryo and a means of dispersal. Seed plants are divided into two major groups: gymnosperms (cone-bearing plants) and angiosperms (flowering plants). Gymnosperms, which include conifers and cycads, produce seeds in cones. Angiosperms, the most diverse group of plants, produce flowers and have more advanced reproductive structures.
4. Flowers and Fruits (Angiosperms): Angiosperms are characterized by their unique reproductive structures, flowers, and the production of fruits. Flowers are specialized for attracting pollinators and facilitating sexual reproduction. Fruits develop from fertilized flowers and aid in seed dispersal, often through interactions with animals that consume the fruits and spread the seeds.
5. Adaptations to Dry Environments: As plants continued to adapt to terrestrial environments, they developed various features to cope with dry conditions. Cuticles became more elaborate, stomata (tiny pores) evolved to regulate gas exchange while minimizing water loss, and roots extended deeper into the soil to access water resources.
6. Co-evolution with Mycorrhizal Fungi: Many terrestrial plants formed symbiotic relationships with mycorrhizal fungi. These fungi attach to plant roots and enhance nutrient absorption, particularly phosphorus. In exchange, the fungi receive sugars produced by the plants through photosynthesis.
7. Diversification and Adaptation: Over millions of years, terrestrial plants diversified into a wide range of forms, sizes, and ecological niches. They adapted to various habitats, including deserts, forests, grasslands, and wetlands. This diversification led to the development of complex ecosystems on land, shaping the planet's biodiversity and ecology.

The transition of plants from marine algae to terrestrial environments was a gradual process that involved a series of genetic and physiological changes. Each step in this evolutionary journey conferred advantages that allowed plants to exploit new ecological niches and eventually dominate terrestrial habitats. This narrative showcases the remarkable adaptability of life and the ongoing interplay between organisms and their environments.

The research, which is published open access in Nature Plants, is explained in a new release from Göttingen University:

Research team led by Göttingen University investigates 10 billion RNA snippets to identify “hub genes”

The Earth's surface is covered by plants. They make up the majority of biomass on land and exhibit a wide range of diversity, from mosses to trees. This astounding biodiversity came into existence due to a fateful evolutionary event that happened just once: plant terrestrialization. This describes the point where one group of algae, whose modern descendants can still be studied in the lab, evolved into plants and invaded land around the world. An international group of researchers, spearheaded by a team from the University of Göttingen, generated large scale gene expression data to investigate the molecular networks that operate in one of the closest algal relatives of land plants, a humble single-celled alga called Mesotaenium endlicherianum. Their results were published in Nature Plants.

Our study began by examining the limits of the alga's resilience – to both light and temperature. We subjected it to a wide temperature range from 8 °C to 29 °C. We were intrigued when we observed the interplay between a broad temperature and light tolerance based on our in-depth physiological analysis.

Janine Fürst-Jansen, co-lead author
Institute of Microbiology and Genetics
Department of Applied Bioinformatics
University of Goettingen, Goettingen, Germany

Samples of Mesotaenium endlicherianum that have been kept safe in the Algal Culture Collection at Göttingen University (SAG) for over 25 years. This image shows the unique experimental set-up there which allowed the researchers to expose Mesotaenium endlicherianum to a continuous range of different light intensities and temperatures.

Photo: Janine Fürst-Jansen

What is so unique about the study is that our network analysis can point to entire toolboxes of genetic mechanisms that were not known to operate in these algae. And when we look at these genetic toolboxes, we find that they are shared across more than 600 million years of plant and algal evolution!

Professor Jan de Vries, Senior author Institute of Microbiology and Genetics
Department of Applied Bioinformatics
University of Goettingen, Goettingen, Germany

Our analysis allows us to identify which genes collaborate in various plants and algae. It's like discovering which musical notes consistently harmonize in different songs. This insight helps us uncover long-term evolutionary patterns and reveals how certain essential genetic 'notes' have remained consistent across a wide range of plant species, much like timeless melodies that resonate across different music genres.

Armin Dadras, co-lead author
PhD student
Institute of Microbiology and Genetics
Department of Applied Bioinformatics
University of Goettingen, Goettingen, Germany

Using a strain of Mesotaenium endlicherianum that has been kept safe in the Algal Culture Collection at Göttingen University (SAG) for over 25 years and the unique experimental set-up there, the researchers exposed Mesotaenium endlicherianum to a continuous range of different light intensities and temperatures. How the algae respond was not only investigated on a morphological and physiological level, but also by reading the information of about 10 billion RNA snippets. The study used network analysis to investigate the shared behaviour of almost 20,000 genes simultaneously. In these shared patterns, “hub genes” that play a central role in coordinating gene expression in response to various environmental signals were identified. This approach not only offered valuable insights into how algal gene expression is regulated in response to different conditions but, combined with evolutionary analyses, how these mechanisms are common to both land plants and their algal relatives.

More explanation is given in the abstract to the team's open access paper in Nature Planta:

Abstract

Plant terrestrialization brought forth the land plants (embryophytes). Embryophytes account for most of the biomass on land and evolved from streptophyte algae in a singular event. Recent advances have unravelled the first full genomes of the closest algal relatives of land plants; among the first such species was Mesotaenium endlicherianum. Here we used fine-combed RNA sequencing in tandem with a photophysiological assessment on Mesotaenium exposed to a continuous range of temperature and light cues. Our data establish a grid of 42 different conditions, resulting in 128 transcriptomes and ~1.5 Tbp (~9.9 billion reads) of data to study the combinatory effects of stress response using clustering along gradients. Mesotaenium shares with land plants major hubs in genetic networks underpinning stress response and acclimation. Our data suggest that lipid droplet formation and plastid and cell wall-derived signals have denominated molecular programmes since more than 600 million years of streptophyte evolution—before plants made their first steps on land.

Dadras, A., Fürst-Jansen, J.M.R., Darienko, T. et al.
Environmental gradients reveal stress hubs pre-dating plant terrestrialization.
Nat. Plants (2023). https://doi.org/10.1038/s41477-023-01491-0

Copyright: © 2023 The authors.
Published by Springer Nature Ltd. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

So, a series of evolutionary responses to stress enabled simple algae to colonize the land, some 600 million years ago, and all terrestrial plants have diverged from that singular event, complete with the evolutionary changes that enabled it to happen.

Creationists have masses of work to do to dismiss this evidence of common ancestry and an earth much older than their cult tell them Earth and life on it have existed. No wonder creationism is a notion in crisis as even religious people are rejecting it as a valid explanation of the observable facts and no serious scientists even considers it as a viable alternative to evolution.

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