Evolution is gradual change over time and usually guided by natural selection. So to take your bird example, lets say some of the birds had slight difference in their songs. If a particular changed song made them better able to survive and reproduce in the current environment and that change were propagated to the offspring of that bird, I'd call it evolution. But if it's just a learned behavior I'd call it adaptation.
I was actually just thinking of a similar case the other day when mowing my lawn. Have you ever noticed that birds (robins in particular) like to visit freshly mowed lawns to hunt for worms? How do they know to do this? I would call this a learned behavior, but at what point does such a behavior become instinct?
"The reason they're doing this is because cities are generally exceptionally noisy with cars, people, machinery, etc."
Just curious how they know that? It sounds like a hypothesis masquerading as a scientific fact.
Agreed. I said the same thing after reading it.
My interpretation of the infallible and unchanging good book (Wikipedia) tells me that Adaptation and Evolution are nearly the same thing, except that Adaptation refers specifically to beneficial changes due to selective pressure, while Evolution applies more generally to change over time.
If I am right, your examples would be both adaptation (because it's beneficial) and evolution.
However, I've also heard it said that the difference is that an Adaptation is the change that a specific individual creature has.
Does anyone else have a problem with the word "adaptation", especially when applied to an individual creature, in that it seems to imply a conscious effort to attain a particular result?
I mean: no individual moths "adapted" to life in a polluted city by changing their wings to a darker color -- the light colored ones just gotten eaten faster.
(I'm referring to the famous Peppered Moth example of recent evolution.)
My first instinct is to say that they are both adaptations, but in reality they are both both. In order to be able to truly define the situations, you'd need to define more variables, including the time frame and whether or not there are differences between generations etc.
As I have learned to understand it, adaptation is a behavior that an individual changes within their lifetime in order to better survive the various stresses in their lives...and this change (with the exception of epigenetics, but for simplicity lets ignore this for now) is impossible to be passed down to their offspring. Yes behavior can be passed on through young learning to mimic their parents or other members of their population, but this is not because they have a gene for the behavior, but instead because they have the genes and instincts required to mimic and learn from their experiences.
Evolution is changes in the genetic code that can then be passed on to offspring, and the results of these genes give the individual a better chance at survival, for example slightly longer arms than average, or a sharper beak, etc.
Adaptation and Evolution are extremely connected. If evolution has given an organism a mutation or difference, they need to be able to adapt to take advantage of this change, or it will be meaningless and will fade out of the gene pool.
To use the peppered moths example:
A species of moths has two colors...a dark, and a light. The light is much more prominent.
Because of increased pollution in a nearby city, the trees the moths live on which normally have a light bark, are now discolored and dark. This means that they dark moths that used to stand out against the trees now blend in, and the opposite for the light moths. Their predators now eat mostly light moths, and after many generations, the allele frequencies of the alleles that cause the dark color has gone up, while the alleles for the light color has gone down. This is evolution. Due to a new stress, the color change of the trees, the darker color is now being selected for within the population.
Now, if we take the same situation, but use adaptation instead of evolution:
the moths could adapt and learn to start landing on lighter trees, avoiding the darker trees, and increasing their rate of survival despite the introduced stress. This behavior would not be passed on by genetics.