We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
Biology

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

When did Animals First Colonize Continental Interiors?

Michael Anissimov
By
Updated: May 21, 2024
Views: 6,013
Share

Animals first colonized continental interiors sometime in the late Silurian or early Devonian, around the same time that extensive terrestrial fossils appear. The first animals to colonize continental interiors were probably insects. Remarkably, the first known insect fossil, Rhyniognatha hirsti, estimated at 396-407 million years old, had already evolved wings, which would have let it travel far inland, as long as there was sufficient food in the form of plants.

The colonization of continental interiors likely occurred around the same time that vascular plants evolved, roughly 425 million years ago, with fossil examples like Cooksonia (northern hemisphere) and Baragwanathia (Australia). Prior to this, terrestrial flora mostly consisted of bryophytes (mosses, etc) that had to be in very wet, usually coastal areas in order to survive.

Of course, life could have spread into continental interiors via rivers, but in this ancient era, due to a lack of land plants, most rivers had a braided rather than winding structure, which made them less hospitable to animals. Once vascular plants really started to get going, they shaped the rivers into a more unified flow, bringing in algae and small aquatic animals. The insects that first made the steps onto land would have been similar to modern-day bristletails, an evolutionary relict which has changed little since it first emerged in the Devonian.

Insects existed on land in small numbers for tens of millions of years, but don't show up in the fossil record in large numbers until the late Carboniferous, around 330 million years ago, when the first true forests began to grow. It is completely possible that insects existed before this, but didn't fossilize reliably due to any number of reasons.

Meanwhile, the first tetrapods, like Acanthostega, began to take their first steps onto dry land around 360 million years ago. For tens of millions of years, they stayed on the coasts and in muddy swamps where were common at the time. But around 340 million years ago, some amphibians evolved a tough membrane around their eggs, making it possible to lay them on land, creating the first reptiles, which resembled small lizards. These animals would have been among the first non-insects to colonize continental interiors, now filled with nutrient-rich forests.

Share
All The Science is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Michael Anissimov
By Michael Anissimov
Michael Anissimov is a dedicated All The Science contributor and brings his expertise in paleontology, physics, biology, astronomy, chemistry, and futurism to his articles. An avid blogger, Michael is deeply passionate about stem cell research, regenerative medicine, and life extension therapies. His professional experience includes work with the Methuselah Foundation, Singularity Institute for Artificial Intelligence, and Lifeboat Foundation, further showcasing his commitment to scientific advancement.
Discussion Comments
Michael Anissimov
Michael Anissimov
Michael Anissimov is a dedicated All The Science contributor and brings his expertise in paleontology, physics, biology...
Learn more
Share
https://www.allthescience.org/when-did-animals-first-colonize-continental-interiors.htm
Copy this link
All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.