Do aliens exist?

[Jarvis323]

What "Happened quickly" is reproducing molecules and single celled organisms. That suggests that only life on that level is common on other planets. The development of anything with a brain took the vast majority of Earth's history.

The time constraints for the evolution of complex or intelligent life are not clear based on Earth's story.

The Cambrian explosion, Cambrian radiation,[1] Cambrian diversification, or the Biological Big Bang[2] refers to an interval of time approximately 538.8 million years ago in the Cambrian Period when practically all major animal phyla started appearing in the fossil record.[3][4][5] It lasted for about 13[6][7][8] – 25[9][10] million years and resulted in the divergence of most modern metazoan phyla.[11]The event was accompanied by major diversification in other groups of organisms as well.[a]

Before early Cambrian diversification,https://en.m.wikipedia.org/wiki/Cambrian_explosion#cite_note-14 most organisms were relatively simple, composed of individual cells, or small multicellular organisms, occasionally organized into colonies. As the rate of diversification subsequently accelerated, the variety of life became much more complex, and began to resemble that of today.[13] Almost all present-day animal phyla appeared during this period,[14][15] including the earliest chordates.[16]

https://en.m.wikipedia.org/wiki/Cambrian_explosion

I would like to know if the rapid emergence of complex life on Earth was only possible from a long evolutionary chain of simple precursor life, or if the right conditions just finally arrived. But it seems life can can transition from "individual cells, or small multicellular organisms, occasionally organized into colonies" to something like us in about 538 million years or less.

 

[DaveC426913]

The time constraints for evolution of complex or intelligent life is not clear based on Earth's story.



https://en.m.wikipedia.org/wiki/Cambrian_explosion

I would like to know if the rapid emergence of complex life on Earth was only possible from a long evolutionary chain of simple precursor life, or if the right conditions just finally arrived.

My Cambrian Biologist sister, Queen of The Burgess Shale, who is sitting across from me on the couch, says "the latter":

(Dictated:)

The first "ediacaran" animals were flat and absorbed nutrients through their skin. The sea chemistry changed, allowing them to grow further up the water column. Also, predation was invented. So was chlorophyll.

Also. "Hydrogen Sulphide Barrier" something.

These are factors that led to the explosion.

She says she can "get the name of the paper when she gets home, but: Mark Laflamme, U of T Erindale".

Also: "Go see the Dawn of Life Exhibit at the ROM! Biggest Cambrian Exhibit in North America!"
She painted the murals for it!

 

[phinds]

Why not chickens or GMO mushrooms that taste just like human, but don't rebel or try to develop technology?

Because it would make for a much less interesting story. It was STORY. Try to keep that in mind.

 

[Algr]

Because it would make for a much less interesting story. It was STORY. Try to keep that in mind.

Dave said it still haunts him, so I was playing scientific exorcist.

 

[DaveC426913]

don't rebel or try to develop technology?

Rebel against what? There's no oversight. No aliens. They eat and they breed in-the-wild across continent-spanning fields. And there's nothing else. You see why it's ghastly? Understimulation.

Develop technology from what? There's not even trees. You can't beat someone to death with a handful of algae.

 

[gmax137]

The honest answer is that no one knows. The statistical argument that it's inevitable as there are so many other stars is actually not valid. It may be that the evolution of life has an extremely low probability that outweighs the large number of opportunities.

...

Well then how do you explain that we "just happen" to be on that unlikely world? I mean, what are the chances that our world happens to be the one?

 

[DaveC426913]

Well then how do you explain that we "just happen" to be on that unlikely world? I mean, what are the chances that our world happens to be the one?

Anthropic Principle says so.

 

[PeroK]

Well then how do you explain that we "just happen" to be on that unlikely world? I mean, what are the chances that our world happens to be the one?

If, say, there is only one advanced civilization per galaxy, then each advanced civilization (by your logic) would conclude they are one of many.

 

[Mark44]

Locked temporarily for moderation...