What was Earth's first predator and when did it live?

[n2doc]

by
Colin Barras
Around the world right now, thousands of animals are about to die. The game is up for untold numbers of deep-sea fish, mountain-dwelling hares, subterranean earthworms and high-flying songbirds. They are all seconds away from becoming dinner for predators like lions, eagles and sharks.

But when did this carnage begin? Have predators stalked the Earth since the origin of life itself? Or was our primordial planet once a Garden of Eden where species lived in peaceful co-existence?

The truth is, no one actually knows for sure. But evolutionary biologists have learned enough about the history of life on Earth to begin the hunt for the first predator. Their work suggests it was about as far removed in appearance from today's killers as it's possible to imagine.

Before we pick up the trail, it might help to spell out what a predator is. According to most biologists, predation must involve the death of one living thing at the hands (or teeth, or claws) of another, which has to gain some nutritional benefit from the kill. A lion is a predator because it kills and eats a gazelle, but the gazelle is not a predator, because it doesn't have to kill the grasses it eats.

more

http://www.bbc.com/earth/story/20141202-what-was-earths-first-predator

[Wounded Bear]

1. To me, it's about effieciency...

Original forms of life took their nutrients directly from the environment. Eventually, life forms "learned" that it was easier to digest/assimilate nutrients that were pre-digested by other organisms by cnsuming them. In that light, the first "predators" were microbes that learned to eat other microbes instead of directly ingesting minerals/proteins from the environment.

[AlbertCat]

3. I suppose the definition excludes molecules...

... stealing other molecules or parts thereof.

I mean... ebola is made up of only 8 proteins, isn't it? Is it a predator or a parasite...or can something be both?


I suppose you get into that argument of when a molecule becomes "life".

[exboyfil]

5. I have always been disturbed about

excluding viruses as life. But if they are included then what about prions?

Life is a somewhat arbitrary designation. If we ever discover another biosphere we may be shocked in how it changes our definitions. One area discussed for study but not fully pursued is looking for microbial forms that are not part of our known Last Common Ancestor. The determination that Archaea represented an independent line of evolution from bacteria is pretty recent and revolutionary. Eukaryotes are believed to be descended from Archaea.

[exboyfil]

2. The first predator would be

some sort of microbial life form, and I bet predation occurred pretty early but we would have no remaining evidence of it. A simple bacteria needs chemicals to survive and what better source of a concentrated form of those chemicals than another life form. Evolution would have quickly moved to that point.

http://www.nrm.se/download/18.4e32c81078a8d9249800021552/Bengtson2002predation.pdf

http://www.pnas.org/content/83/7/2138.full.pdf

[longship]

4. Yup! That's it. nt

[NickB79]

7. Multi-cellular, eukaryotic life was only made possible by predation

The mitochondria and chloroplasts found in animal and plant cells today are the remnants of a failed predation moment: one cell attempted to absorb a smaller one, and the smaller one found a way to survive and reproduce inside the larger one in an amazing act of symbiosis: http://en.wikipedia.org/wiki/Symbiogenesis