Swallows Seem To Be Evolving to Avoid Cars

[thesummerqueen]

Because they haven't actually CHANGED anything about themselves, all that's happened is that they've responded to environmental conditions with their existing genetics.

Natural selection is the gradual, non-random process by which biological traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution.

Evolution is the change in the inherited characteristics of biological populations over successive generations.

During a 30-year study on social behavior and coloniality of cliff swallows (Petrochelidon pyrrhonota) in southwestern Nebraska, we found that the frequency of road-killed swallows declined sharply over the 30 years following the birds’ occupancy of roadside nesting sites and that birds killed on roads had longer wings than the population at large.

For 30 years, swallows with the genetics for longer wingspans were being killed. The swallows with the genetics with shorter wingspans were surviving longer and passing off those genetics to their offspring. One set of genetics survives the other. Most of the population, therefore, changes to being shorter-winged.

If the conditions suddenly "changed back" they would develop as they previously had. Evolution is directional - it doesn't go forwards and backwards and concerns the development of new features, not the preference for existing ones.

Wrong. Evolution does not move in a linear fashion, as I previously stated. Either through artificial or natural selection, the animal that (sometimes best, but sometimes only 'just good enough') fits the required conditions for the environment 'wins' the genetics game to fuck and pass on offspring. If this means that all the cars leave, swallows with shorter wingspans MAY survive, but a better chance at surviving goes to those with longer wingspans to do whatever it is swallows do besides carrying coconuts.

Case in point: we have huge brains. We have shitty 'other' defense mechanisms. If we wish to survive against a tiger or bear, we have to use these brains to build tools, because we have...nothing else. As our brains evolved and we used tools, we lost our protective hair covering, any nails of significance, our canines, our strength, etc.

Actually, the human body is a bit like the genie in the movie Aladdin.

COSMIC PHENOMENAL POWERS!!!....itty bitty living space.

The default position in science is scepticism, ie "I don't know".

What on earth did this have to do with the price of tea in China?

evolution requires significant development and change for it to be a clear example of evolution.

Translation: "I wanna see a crocoduck!!!"

What you have an example of is the species preferring specific genes in a specific environment.

HOLY FUCK YOU WERE SO CLOSE TO THE GOLD HERE I ALMOST WET MYSELF

No one has demonstrated that the shorter wings are a newly developed feature or a new gene, or anything of the sort.

Wing length is determined by genes. Doesn't have to be 'new'.

The article linked to is completely laughable as far as scientific credibility goes, I don't know why you're defending it.

Please, regale me with why it's laughable - did you even click the link to the study IT linked?

It's like any selective breeding that we do.

Yes, Rhythm and I discuss all the time how artificial selection caused corn/maize to be evolved from a pissant little grass to gold deliciousness. Do keep up. I'd link it, but I'd rather you search it and link it to prove you know how to use google.