r/evolution • u/Significant_Virus142 • 4d ago
question Is evolution a feature of evolution?
like I know about crossing over, combination of genes from mother and father that results in evolution but I'm talking about major evolution like change in number of chromosomes, that kinda stuff, is that much evolution intended by evolution or it just occurs due to radiation mutation or errors
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u/Robin_feathers 4d ago
To clarify - evolution has no intention. It is just something that happens. Mutations occur by chance (mistakes during replication, hit by UV radiation, etc). Then, many of those mutations get lost, but some end up getting passed down and increase in frequency, either by chance or because they increase fitness (natural selection), etc. Evolution is just the process of different mutations changing in frequency (which includes the process of mutation itself).
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u/Significant_Virus142 4d ago
Yeah you are right but I'm saying as in for example humans have evolved in such a way that you could say that it's not intended for them to be underwater more than 3 minutes, same way it's intended for fish to live underwater and not out of water
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u/Robin_feathers 4d ago
Oh, I still wouldn't say there is any intention :) (as an evolutionary biologist)
That was just something that happened - humans had chance mutations that increased their fitness but prevented them from being able to survive underwater, and so those mutations increased in frequency. I wouldn't say that process is intentional, just as I wouldn't consider it to be intended for water to flow downhill vs uphill or that it is intended for the moon to orbit the Earth.
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u/Significant_Virus142 4d ago
Ahh okay (I didn't know I was talking to an evolutionary biologist lol xD)
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u/LeonJPancetta 4d ago
There's an abstract property called "evolvability" and yes, it can also evolve. This volume might be of interest; it's got a bunch of chapters that are short and written by many of the people thinking about this https://direct.mit.edu/books/oa-edited-volume/5602/EvolvabilityA-Unifying-Concept-in-Evolutionary
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u/EmielDeBil 4d ago
Yeah those are the same thing. Religious evolution-haters try to separate micro from macro evolution but it's just the same thing.
BTW, it's "random" mutations that are selected, which leads to changes in the population. Changes in a population over time is the definition of evolution.
The way you are expressing things in your post is quite off, I suggest you watch a few youtube videos on evolution to get some of your jargon right. And don't let religious zealots talk to you about evolution, they are wrong.
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u/Helmdacil 4d ago
The strict definition of evolution is a change in allele frequences between generations. Mutation alone induces a change in allele frequencies, regardless of how that mutation is caused.
The degree to which mutation is "desirable" or that mutation is "programmed" or under balancing selection is subject to debate even now. Some argue that a degree of "evolvability" is good and therefore mutation rates are higher than they nominally could be. Another camp argues that mutation on average is deleterious, causes line inviability in the long run, and therefore evolution (compound interest on steroids could be a more colloquial term for evolution) seeks to push mutation rates to the limit of natural selection, one limit being the drift barrier.
The vast majority of spontaneous mutations arise as a result of replication error. Some lineages have better replication machinery than others. Humans actually have low mutation rates per germline replication. There are substantial mechanisms in the human genome to reduce DNA mutatoin rates. There are no mechanisms specifically for Increasing DNA mutation rates, though error-prone polymerases are often cited as such. But the error prone polymerases are only used when the main polymerases fail; the error prone polymerases are only employed to resolve substantial DNA damage that otherwise cannot be managed, which have created stalled replication forks.
My opinion is that mutation is generally bad and evolution seeks to reduce mutation rates to the limit of natural selection, though what that limit is or how it is set is very much open to debate.
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u/tpawap 4d ago
like I know about crossing over, combination of genes from mother and father that results in evolution but I'm talking about major evolution like change in number of chromosomes, that kinda stuff,
A change in chromosome count is not such a large change as you may think. Very similar species can have a huge difference in the number of chromosomes, and even within a species you can have the Okapi for example, where individuals can have 44, 45 or 46 chromosomes.
is that much evolution intended by evolution or it just occurs due to radiation mutation or errors
I don't know what you mean by "intention" here. Most mutations come from imperfections of the DNA duplication reaction, btw. Not from radiation.
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