Theories on how the food supply evolved along with life?

[Robert P]

TL;DR Summary

At all stages of evolution there had to be a suitable food supply

Along with the endless complexities of life and the evolution of life, it occurs to me that at all points there had to be enough available nutrition for existent life forms - and that food supply itself had to go through a process of evolution. It seems self-evident that the environment of early Earth wouldn't have supported dinosaurs or homo sapiens. And of course even today not all life forms are suited for all environments.

What are current theories on how this progressed?

 

[Baluncore]

The food chain is not a simple chain, but a braided network. The food supply is also life, so a food source must evolve before it can be consumed.

 

[Drakkith]

Other than the very earliest stages of abiogenesis and biological evolution, when simple chemicals from the environment were gradually turned into more complex compounds through some ultimately unknown processes, life has always preyed upon other life for food or made 'food' from photosynthesis or chemosynthesis. So the history of the evolution of food is simply the history of the biological evolution of life itself.

 

[256bits]

Here is a picture of the Earth's carbon cycle, I suppose present day.
Note the geological underpinnings, besides the biological.

You can access
https://www.khanacademy.org/science/biology/ecology/biogeochemical-cycles/a/the-nitrogen-cycle
for some other cycles.

 

[hutchphd]

Yep that's just the way I would design it...wow

 

[BillTre]

You are correct that ecology startted out simple and then got more complex, like most things biological.

In 2017, Olivia Judson published a paper, not (directly) on how the changes in the food supply over evolutionary time periods, but the changes in the energy sources available for life to use. This is a highly regarded article, it takes a large scale view.

• original article
• https://www.researchgate.net/publication/316561085_The_energy_expansions_of_evolution
• popularized version

Her sequence of different energy sources is:

1. geochemical energy: probably used by the "first life forms"
2. sunlight: available to use after photosynthesis arose.
3. oxygen: had to wait for cyanobacteria to make oxygen which then provided a large increase in the amount of energy that could be got from food items (as much as 16x the amount of energy obtained from a glucose molecule).
4. flesh: oxygen highly mobile predators able to eat other (large) organisms.
5. fire: used only by humans, to cook (pre-digest) food to be able to more easily and more rapidly get more nutrients from certain foods (like meat).

Here is a short Wikipedia article on evolution of ecology.

 

[Laroxe]

I think I would be careful of the idea of the evolution of food, as Drakkith suggests, life evolves and has indeed become increasingly complex but as most forms of life use the same "chemistry", its not surprising that some lifeforms would evolve to exploit this source of "pre-processed" nutrition. In evolutionary terms, the main selective forces, will be ones that have favoured changes that resisted predation or used some aspects of this predation to facilitate the preys reproduction.

The relationships between different forms of life in an ecosystem can be complex, but nothing has evolved simply to be a food source for other species and understanding the complex networks of interactions is what should form the basis of ecology as a subject of study.

 

[hmmm27]

but nothing has evolved simply to be a food source for other species

except the massive variety of plants which count on their seeds being eaten and sown.

 

[hutchphd]

This really is a chicken and egg (and corn and wheat and fox and worm and hawk and ...) argument.

 

[BillTre]

The egg came before eggs.
Reptiles had eggs before there were birds.

 

[pinball1970]

The egg came before eggs.
Reptiles had eggs before there were birds.

I thought I had someone wandered back into the Chicken egg thread!

 

[Laroxe]

except the massive variety of plants which count on their seeds being eaten and sown.

I don't think there is an "except", plants have put a great deal into reaching the point that they are able to reproduce and there is a huge variety of methods that they use. Its only really at the reproductive stage that plants have developed ways of manipulating the behaviour of other species, often with food or the promise of food to increase their own fitness. However this doesn't really imply that this represents the plant evolving to become a food source which in itself would make no sense, what has evolved is a trait to improve fitness.

Plants which are very poisonous or covered with spines may still provide food at specific times to pollinators or specific animals that distribute their seeds and even this can involve highly conditional relationships which may have co-evolved.