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from the only-if-Betteridge-is-not-on-it dept.
How predictable is evolution? The answer has long been debated by biologists grappling with the extent to which history affects the repeatability of evolution.
A review published in the Nov. 9 issue of Science explores the complexity of evolution's predictability in extraordinary detail. In it, researchers at Kenyon College, Michigan State University and Washington University in St. Louis closely examine evidence from a number of empirical studies of evolutionary repeatability and contingency in an effort to fully interrogate ideas about contingency's role in evolution.
The question of evolution's predictability was notably raised by the late paleontologist Stephen Jay Gould, who advocated the view that evolution is contingent and unrepeatable in his 1989 book Wonderful Life. "Replay the tape a million times ... and I doubt that anything like Homo sapiens would ever evolve again," Gould mused, noting that being able to "replay the tape" and give history a do-over would be impossible. Yet since the publication of Wonderful Life, many evolutionary biologists have taken up this challenge and conducted their own versions of Gould's experiment, albeit on smaller scales. In doing so, they have reached different conclusions about the interplay between randomness of mutations, chance historical events, and directionality imparted by natural selection.
[...] Their review of comparative studies of "natural experiments" further illuminated evidence of evolution's predictability. Similar features can independently evolve in multiple species—for example, anole lizards of the Caribbean, which separately evolved traits such as the length of their legs and tails to ease their life in their specific habitats. Yet convergence in evolution does not always occur, as their review shows; contingency can play a strong role in divergent evolution of various traits.
Replaying the tape of life: Is it possible?
[Abstract]: Contingency and determinism in evolution: Replaying life’s tape
[Source]: IS IT POSSIBLE TO REPLAY THE TAPE OF LIFE?
(Score: 2) by Arik on Friday November 09 2018, @03:54PM (3 children)
However there is more there, and Shannon in my view is probably pointing us in the right direction there, at least vaguely. DNA itself functions as an information system of sorts.
My own hunch (and of course it's just a hunch) is that if you ran the "experiment" a million times you would always or nearly always get something *like* homo sapiens at approximately the same point in time. The argument might turn into how like is like though, and how close is approximately even.
The closest we could get to doing the experiment is probably directed panspermia i.e. sending out probes to intentionally contaminate empty worlds with some hardy form of DNA; blue-green algae perhaps. Then come back in a few million years and see what happened.
Of course on some worlds it might simply die out, but on those where it was able to survive and reproduce, I suspect you'd find evolution would then work much the same on any world going forward. Simple forms would not die out - but more complex forms would evolve to better exploit certain situations. Then the situations would change, forcing the more complex forms to either change quickly or die out entirely (in which case simple forms take back over and the process just starts again.)
Both would happen, but rinse and repeat long enough and you get a warm blooded mammal adapted for exhaustion hunting, and social organization, and it will develop language, art, math, and if it manages to survive long enough it will start to poke it's head back out of the gravity well.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by Bobs on Friday November 09 2018, @08:19PM (1 child)
I see where you are going. just remember humans are not necessarily the ideal, end, equilibrium state for life.
On this planet, dinosaurs got there first and ate the mammals for 100s of millions of years. And though more than 1 extinction event.
Us humans wouldn't be here at all if the dinosaurs hadn't gotten wiped out by a large, fast rock.
And the amount of time humans have been top animal isn't even a rounding error for the amount of time the dinosaurs reigned.
(Score: 2) by Arik on Friday November 09 2018, @09:00PM
Of course. Not anymore than a late-term fetus is the ideal, equilibrium state of human life.
Each is simply a brief stage that may (or may not) lead to the next one.
"Us humans wouldn't be here at all if the dinosaurs hadn't gotten wiped out by a large, fast rock."
Perhaps, perhaps not. Ever read /"West of Eden/"?
If laughter is the best medicine, who are the best doctors?
(Score: 2) by deimtee on Saturday November 10 2018, @08:25AM
The two or three billion years between first life and multi-cellular life indicate that the tough part is going multi-cellular. Once that happens diversity explodes.
You might want to seed those planets with small animals and tiny plants as well, some time after the algae.
If you cough while drinking cheap red wine it really cleans out your sinuses.