Human evolution question?

[Warden_of_the_Storm]

Do you get how all creatures have an impact on their environment? North American megafauna may have led to the distribution of various plants who's range was already contracting by the times the Europeans arrived in force. Beavers have a huge impact. So do prairie dogs; just ask anyone with horses. Sheep and cattle famously don't mix well due to sheep's impact on the environment. Alligators will clear places for themselves that tend to hold water during droughts. Or look at the impact that elephants can have on fauna.

If humans are as much an animal as those named above, then why treat what humans do as a different trait than every other animal on the planet?

If, however, you contend that humans are something apart from animals, as is held by Christian belief, then that is another discussion.

I feel that you're being very blase about the way humans are capable of treating the world we live in, especially since you ignored what I began the comment you quoted with. At least with other animals, the way they interact with the world is actually something more inline with synchronicity; one act they do has the effect of aiding another species, like snakes using gopher/prairie dog burrows as their own homes, alligator holes create places for other animals to acquire water in droughts and act as wetland 'engineers' as it were.

I'm not disputing that other animals have an effect on their local ecosystem, that is an indisputable fact, nor that humans are animals. But when humans create a dam that holds so much metric tonnage of water that it slows the rotation of the earth... can you claim that's something natural? Or how about humans creating vast quarries that are so destructive and polluting to the natural habitat that they essentially are ruinous for years, decades to come. Is that REALLY comparable to beaver dams and prairie dog burrows and alligator holes?

It's not an appeal to Christian belief about the superiority of man (which I do not agree with) to point out that a lot of the things humans made really cannot be called natural. To just go "Oh, humans are animals too, so anything we do is natural" is ignoring a lot of negatives about human interaction with the world that have a lot of negative consequences.

However, I think that we can definitely say that such a topic is very off-topic and doesn't really address evolution.

 

[Warden_of_the_Storm]

If human evolution is still happening (and I can’t imagine why it wouldn’t be), wouldn’t it be very difficult to detect over only a thousand years?

Could you call the lack of wisdom teeth, or rather the problems from complications of the eruption of wisdom teeth, in certain world populations evolution? Human diets are now heavily geared towards soft foods, cooked or otherwise, thus eliminating the need to chew so heavily and thoroughly.

 

[Tuur]

I feel that you're being very blase about the way humans are capable of treating the world we live in, especially since you ignored what I began the comment you quoted with.

First, since the topic is human evolution and what led to this particular discussion is that implication that human evolution at this point is "unnatural" since it's shaped by "unnatural" changes to the environment. Second, if I'm very blasé, it's in a cold equations sense. I never argued that all the modifications humanity makes to its environment is good. I'm only arguing that modifying our environment is a natural for humans, therefore any evolution as a result is natural as well.

As to what we and all creatures do to their environment, I mentioned elephants for a particular reason: Too high a concentration of elephants in a given area strips vegetation bare and is ultimately detrimental to the herd and other creatures. And yes, there are animals that have prospered with human modification of the environment; some, like the rat, we don't particularly care for. If you want to point out we can and have destroyed vast swaths of habitat with the animals that lived there, I'll agree. If you want to point out that on occasion this has been detrimental to humans, I'll agree with that, too. Just like elephants, we don't always act in our best interest.

 

[sfs]

Because shuffling the distribution of genes in an environment doesn't produce changes like the number of genes a species has. For that you need mutation.

Sure, but why does that mean we shouldn't have a word for all of the genetic changes to a population? Mutation is part of evolution, but so is natural selection, and so is genetic drift. Evolutionary biology studies all of them, along with speciation, hybridization, extinction, and so on.

 

[Tuur]

Sure, but why does that mean we shouldn't have a word for all of the genetic changes to a population? Mutation is part of evolution, but so is natural selection, and so is genetic drift. Evolutionary biology studies all of them, along with speciation, hybridization, extinction, and so on.

The word "adaptation" fits nicely. Evolution of species is like going from a poker deck to a pinochle deck, and you can't do that by shuffling.

 

[Ophiolite]

The problem is practically everything related with biology gets called evolution even when it's a stretch. A survey of genes in a population is a survey of genes in a population, no more, no less, and that can change by factors such as shifts in population or (at the risk of being called a Lamarkian) effects of environment on existing genes. A change in the proportion of existing genes shouldn't properly be called evolution since that's not a change to the genes themselves.

The mutation that caused blue eyes, now that was a change to the genes, a mutation. At one point maybe 6,000 to 10,000 years ago it didn't exist and now it does. It wasn't something floating around in the general population here and there and only really showed up due to a population shift. That is what properly should be called evolution.

With your permission I would like to use this post and your earlier ones on the topic as a type example of the Dunning-Kruger effect. Or, to put it more politely: disagreeing with the definition of a evolution when those engaged in the study of evolution confirm that definition is not very sensible.

 

[sfs]

The word "adaptation" fits nicely. Evolution of species is like going from a poker deck to a pinochle deck, and you can't do that by shuffling.

The word 'adaptation' fits one small part of evolution nicely -- which is why we use it for that part. We often have no idea whether a particular evolutionary change represents adaptation or some other evolutionary process, so what word should we use then? Sometimes we don't know whether a change involves a new mutation or not. What word would we use then? Seriously -- why are you trying to tell me how to do my job? (Oh, and your analogy is wrong: it's quite possible for a species to split into two without any new mutations occurring. Sorting of existing variation could do it.)