MAR 06, 2015 4:58 AM PST

Evolution of Animal Functions Came About Slower Than Originally Believed

The field of paleobiology and the study of ecological diversity have some new data and it's proving to be quite different from what most theories of animal evolution have previously posited.
Researchers categorized over 18,000 genera in their analysis of ecological diversity
Researchers from Stanford University have recently completely a comprehensive analysis of marine fossils which demonstrates that the evolution of ecological diversity (which relates to what animals do) did not follow the pattern as the evolution of taxonomic diversity (which relates to how animals look) Instead, ecological diversity developed at a much slower pace, culminating with the huge variety of animal functions that exists today. Stanford researchers found that ecological diversity came about much slower than originally believed.

"The fossil record provides clear evidence that the basic body plans that all marine animals follow today evolved around the time of the Cambrian explosion 542 million years ago and almost all subsequent new species are variations on those themes," said Stanford paleobiologist Jonathan Payne, who is a coauthor on a new study detailing the findings. "But what animals have been able to do with those body plans has changed dramatically, and took much longer to reach the point that we see today."

In the study, published online on March 4 in the journal Nature Communications, Payne and his colleagues challenged a long held theory originally proposed by famed evolutionary biologist Stephen J. Gould and others that the evolution of ecological function underwent an "early burst" at the very beginnings of animal life, similar to that of body plans.
Payne's research team did this by painstakingly categorizing two-thirds of the entire marine animal fossil record according to specific criteria related to ecological function. The scientists took each genus of marine animals and assigned it an "ecological mode of life"-essentially a large number of factors related to a creature's habitat, how mobile it is, and its feeding mode.

In one example, they assigned a different ecological mode of life to a sea sponge whose habitat is the sea floor and which feeds on organic particles wafting by on ocean currents than they did to a tuna, which swims through the ocean and preys on other fish. The team assembled this data for more than 18,000 genera and revealed how the functional diversity of marine animals has evolved through time. This was the first time such a large body of evidence was collected and analyzed and the result was not what they expected.

"Our evidence is very clear that, unlike basic body plans, the ecological functions of animals did not appear in an early burst at all. Rather, it's quite the opposite," said Matthew Knope, a former postdoctoral researcher in Payne's lab and the lead author of the new study. The team estimates that today's vast ecological diversity in animal functions has taken almost 542 million years to develop.

Payne's group was also interested in the question of biological trends. A previous study by the team found fresh support for Cope's rule, a theory in biology that states that animals tend to evolve toward larger sizes over time. The team discovered another trend, that of the increase of ecological diversity over time.
"What's striking is that unlike body size, which exhibited gradual, long-term trends, there were big jumps in ecological diversity after mass extinction events," Payne said.
Some scientists refer to the current loss of biodiversity caused by human activity as The Sixth Mass Extinction and see these findings as hope that the Earth can recover, though it might take millions of years.

"Life may rally back from the current mass extinction," Payne said, "but that recovery will never be seen by humans."
About the Author
  • I'm a writer living in the Boston area. My interests include cancer research, cardiology and neuroscience. I want to be part of using the Internet and social media to educate professionals and patients in a collaborative environment.
You May Also Like
JUL 20, 2020
Earth & The Environment
Ectotherm thermal physiology puts amphibians at even greater climate risk than previously recognized
JUL 20, 2020
Ectotherm thermal physiology puts amphibians at even greater climate risk than previously recognized
Things aren’t looking good for amphibians. According to new research published in Global Change Biology from Simon ...
AUG 20, 2020
Plants & Animals
Honoring World Mosquito Day
AUG 20, 2020
Honoring World Mosquito Day
August 20th, 2020 is World Mosquito Day. Why celebrate an animal dubbed as one of the “world’s deadliest&rdq ...
AUG 27, 2020
Chemistry & Physics
Pheromone Molecule at the Center of Global Locusts Crisis
AUG 27, 2020
Pheromone Molecule at the Center of Global Locusts Crisis
Since earlier this year, agriculture and food production in the developing world have been taking heavy damages from an ...
SEP 06, 2020
Technology
Can Math Determine The Sex of a Dinosaur?
SEP 06, 2020
Can Math Determine The Sex of a Dinosaur?
Can math tell us about the gender differences in dinosaurs? A new study published a novel statistical analysis that esti ...
OCT 06, 2020
Cell & Molecular Biology
How a Carnivorous Plant Creates a 'Memory'
OCT 06, 2020
How a Carnivorous Plant Creates a 'Memory'
The Venus flytrap (Dionaea muscipula) is a famous carnivorous plant that can capture and consume insects and even small ...
NOV 01, 2020
Plants & Animals
Plant Hormone Auxin Helps Orient Growth of Plant Veins
NOV 01, 2020
Plant Hormone Auxin Helps Orient Growth of Plant Veins
There are veins in plants that move nutrients and other important molecules around. These veins have to be carefully org ...
Loading Comments...