Sponges Likely Paved the Way For All Life on Earth

By Jennifer Viegas

March 9, 2014

Summer:

Sponges could have been one of the key organisms that helped turn the Earth from an anaerobic planet to an aerobic planet. They caused this change from their appetite. As sponges feed they filter out parts of organic matter from the water. Going back 700 million years ago when the first sponges emerged, the organic matter would have included dead microbial matter. This matter consumes oxygen. With the sponge getting rid of some of the matter, the oxygen became more abundant. As the oxygen levels rose, it set up the environment for more complex organisms to form. DNA analysis proves that sponges emerged 700 million years ago, when there was very little oxygen in the water. Over the span of the next 100 millions years the oceans became very rich in oxygen, supporting the sponge theory even more. It is known that terrestrial species were derived from marine species, tying all complex life back to sponge for it's change in the environment.

Relevance:
This article relates to unit 8 on microbes. It talks about the formation to obtain a very high oxygen level instead of carbon dioxide, unlike Venus and Mars which are uninhabited because of those conditions. Sponges were one of the main contributors to aerobic life, which had started in the ocean, and have been found in stromatolites. It also relates to DNA analysis and how accurate scientist can pin point certain time periods to prove how certain species effected Earth's environment. Therefore it ties into the evolution of the Earth and how no matter however small and simple an organism can be, it can leave a monumental impact.

URL: http://news.discovery.com/earth/oceans/sponges-likely-paved-the-way-for-all-life-on-earth-140309.htm