The first cells "ate" chemicals. They don't have a digestive system or anything. The cell wall lets whatever the chemical that is food to go through and enter the cell. Inside the cell, a chemical reaction is performed that releases energy. The cell stores the energy in some other form (modern cells store it as ATP) and releases whatever the result of the chemical reaction was as waste.

There was plenty of food around by the time of the first fish.

The first fish mated with whatever its ancestor species was. Its ancestor would have been like 99% of a fish and would have been reproductively compatible. Evolution is very gradual.

The plant/animal split occurred was before animals got as complex as fish. Remember that the much simpler plankton is composed of both plants and animals.

HTH

 

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So as easy as all this is, there should be life on about EVERY rock floating around in space, got it.

 

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Yep, pretty much...


But keep in mind - according to our predominate Religious Dogma. We are the center of it all and 'special'...

 

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Every rock with liquid water. That's the tricky part so far.

 

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no, because the conditions on every rock floating around in space don't match the way life likely originated on Earth, which is sort of the ultimate case of right place, right time. it's certainly plausible that life exists in some for somewhere else in the universe, but way less probably that the exact same conditions occurred in exactly the same way, so who knows what form it could take?

check out abiogenesis, along with evolution, it's more related to the question you're asking.

https://www.google.com/search?q=abiogenesis

 

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This. If a planet is too close to its parent star that water can't remain in liquid form, it doesn't give those chemicals enough time to settle and form stuff. Conversely, if it's too far away, the water will instead be ice, which also kind of makes it hard for life to form/evolve.

It's funny that some posters here post adamantly exactly how it happened. When Dawkins himself admits that "the most profound unsolved problem in biology is the origin of life itself". Science experiments have never synthesized a "protocell" using basic components which would have the necessary properties of life. There is no doubt evolution occurs, but origin of life and the mechanism is unproven.

Time is the tricky part, from our perspective on reality. Lots has passed. Not every rock had the conditions needed for specific chemical reactions that chained into STABLE chemical reactions(lifeforms). Even those that did, might not have stayed that way and the odds are pretty slim such conditions lasted throughout any evolutionarily useful time frame in most places.

But yea, there "could" have been life(of a sort)blasted into existence along with the rest of these mysterious bits space time and matter tossed into the universe. But I'd bet most of it never got past the pre digestive stage.

 

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Hard to tell millions of millions of years after, but most ideas are along the lines of:

The most primitive life probably used what we today call non-organic chemicals and compounds to sustain itself and keep going. Eventually variants and other deviations of the most basic life came to be, to adapt to new environments, etiher by chance or by directed mechnisms. But afaik the process isn't exactly known fully (evolution attempts to cover some things - you may want to look into the works of Darwin etc.).

So by the time you're thinking about "fish", "trees" and so on already 100s of thousands of different species existed in complex systems and co-dependance, they never lived in isolation.

But the thing is the most basic life forms probably existed in parallell all the time with the more advanced forms; see Plankton today, plankton are very primitive and also exist in both animal and plant form, and eat eachother and are eaten by higher forms. Bacteria and other single cell organisms still exist, and are still part of the eco-systems, and so on.

 

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