“Urban wildlife”: animals that traditionally were found only in wilderness areas far from human habitation, that now are making their homes in suburban or even urban environments. My question is, is this an example of microevolution? Are we seeing animals being selected by their ability to tolerate the presence of humans? Or is it that humans formerly would drive away or prey on animals that are now protected?
I don’t have any evidence, but I believe that the latter is most likely in the case of animals like cougars and coyotes. It’s not longer as acceptable to shoot them on sight so they are able live closer to towns. For smaller animals a factor may be that we now keep our dogs and cats under more control. I imagine that free range pets killed a lot more of the town wildlife in the past.
Evolution probably is less an explanation just because of the limited time that towns have been common. However, it’s inevitable that some species will evolve to better exploit urban life, and I’m sure the process has already begun. If you think rats and mice are annoying now, wait till they evolve resistance to all our poisons and the wariness to avoid any traps we set.
The classic example of microevolution is, in fact, an adaptation to urban habitat: The coloration of the peppered moth in London. Peppered moths are colored to match the bark of trees, to hide from predators. During the industrial revolution, tree trunks became darker from pollution, and the moths also grew darker to match. When London started cleaning up, the lighter color returned.
Micro- and macroevolution are terms I’ve encountered only in fundamentalist arguments against evolution. I’ve never found a scientist who said they had any meaning.
I think macroevolution is how we get macrobiotics.
Cats have been evolving alongside humans for several thousand years, now. They’ve adapted perfectly to the urban environment.
I don’t know if this is an example of this or not, but I’m always struck by how much faster urban flies are than the flies you run into in the mountains. They appear to be a similar species, but the city ones are basically impossible to squish without sneaking up on them with a fly swatter, whereas you can catch the mountain flies with your bare hands. I’ve always assumed this was just due to generation upon generation of urban flies being subjected to humans squishing them and only the really quick ones surviving, whereas in the mountains the chances of them coming upon something nimble enough to squish them is pretty low.
I suppose it could be though that the flies in town are just a particularly fast species of fly that does well in urban areas.
It’s always a few degrees warmer in the city then the countryside, maybe many degrees if we’re talking about mountains. Lack of environmental heat limits insect activity.
edit: and DocCathode is right – use of the term “microevolution” implies at least confusion.
Macroevolution is used to describe changes in populations above the species level, while microevolution is used to describe changes within populations below the species level. These are terms used (to varying degrees, depending on one’s background) within evolutionary biology, and are not constructs by creationists.
Hmm, based on the post of Darwin’s Finch I withdraw my objection.
Why are they so used? It’s all “evolution” isn’t it? We don’t have terms for “evolution” that takes place to the left of the speaker as opposed to his right, for example. Why not just say “evolution in this particular population”? Especially since the macro- and micro- terms are so important to Creationist arguments.
The word ‘evolution’ is being used in this thread when what is really being discussed is ‘adaptation’. These are not the same thing.
These urban animals are adapting to a new environment, but they are not evolving as a species. It is an important distinction.
They are so used because there are different survivability patterns seen at the macro-level vs the micro-level. At the micro-level, we talk, for example, of differential reproduction based on traits possessed by individual organisms; at the macro-level we see phenomena such as mass extinctions and punctuations in the fossil record. At the micro-level we see changes in gene frequency within populations; at the macro-level we see lineages emerge and the formation of clades. Sure, it’s all evolution, but it is often helpful to use different terms for different scales of evolution.
Creationists, of course, don’t “get it” in the first place, so it doesn’t really matter how they use - or, more frequently, misuse - terms. We shouldn’t limit our terminology based on what they do or do not understand.
Adaptation (as a process) is evolution via natural selection. These urban animals may not be evolving as a species, but individual populations are certainly evolving.
I don’t get the distinction you’re trying to make. The urban population of our hypothetical organism is evolving – gene frequencies are changing in response to selective pressures.
I don’t get your species distinction. If the non-urban and urban populations of our organism ended up not breeding much with each other for whatever reason, the urban population might eventually become different enough to be considered a separate species.
Yes, adaption in the non-evolutionary sense, occurs. Some individual animals become habituated to humans, learn where to find food, learn to avoid getting hit by cars. If they manage to raise young, the next generation will grow up in the town and learn all those lessons from the start.
But I do think the OP was referring to gene-frequency shifts that will make future generations better able to survive in urban environments. Logically, that will be happening, though I don’t know of any research along those lines.