I have read a lot about Darwin’s voyage, and I know and understand about favorable “random genetic mutations” as well as natural selection.
What I don’t understand, is when source (a) tells me that “humans have evolved to meet the needs of an ever changing world” and source (b) tells me “humans have adapted to meet the needs of an ever changing world”.
Is there any actual difference between the two?
Adaptation can refer either to evolution, or to processes that take place in much shorter periods of time–and generally to the latter. This latter part does not involve evolution at all, because there isn’t time for it. Over the last hundred thousand years, humans have adapted to many things, including living in extremely varied climates. During that time, though, we haven’t evolved much.
LL
You probly coulda taken this one to the dictionary, but oh well.
Evolution generally applies to the development of a new species, and occurs over many, many generations, while adaptation (the official form of adaption) can occur in a much shorter time span, even within a single organism.
I see.
So the only real difference is the time span involved?
Actually no. The time-span involved has little to do with it in an absolute sense. The real is difference is that evolution involves genetic changes that permanantely affect the species, and may create a new species given sufficient change.
Evolution tends to take a long time to cause significant change in a species but it does not have to. New genetic mutations may arise suddenly.
Think of adapation as deer changing their eating strategy to adapt to a suburban rather than an envirnoment uninhabited by man. Adaptions are commonly behaviors that would be reversed if the environment changed back to its former state. I am sure you can think of many other examples.
Evolution results in permanent changes to a species’ DNA that could only be altered by still more mutations.
I wouldn’t quite characterize evolution and adaptation the same way some of the posters before me have.
To pick a broad definition of evolution, I would say it’s changes in the genetic characteristics of a population over time. Given long periods of time, these changes can lead to the development of new species, but as mavpace said, sometimes changes can occur rapidly: new species can develop through an accidental increase in the number of chromosomes (polyploidy) rather quickly.
Adaptation can be confusing because it is often used in two senses: physiological adaptation and evolutionary adaptation.
Physiological adaptations are changes in an organism in response to its environment. An example could be changes in your heart rate and breathing rate if you were to stay at high elevation in the Andes. These can’t be passed on to offspring and are not evolutionary.
An evolutionary adaptation is a change in the features (internal or external) or behavior of a type of organism that is useful for better survival or reproduction in an environment. An example are the different beaks Darwin’s finches developed that are more efficient for feeding on specific types of food. In order to be an evolutionary adaptation, it must be something that can be passed on to offspring.
I think there’s another word for physiological adaptations that could eliminate this confusion, but I can’t remember it right now. (Acclimiation? I’m not sure… I’ll have to check a textbook later).
From ‘Henderson’s Dictionary of Bilogical Terms’
adaptation. The process by which an organism becomes fitted to its environment
evolution. The gradual development of organisms from pre-existing organisms since the beginning of life
From that I gather evolution refers to the gradual changes that take place in populations that make them more sucessful. Adaptation is the process by which it occcurs.
Saying humans have evolved means that we’ve developed to meet the needs of an everchanging world.
Saying humans have adapted means that we have undergone a process that makes us more fitted to our surroundings in order to meet the needs of an everchanging world.
Fairly minor differnce, more paraphrasing than anything. Evolved means we developed, adapted says we developed and tells us why, 'to meet the needs of an everchanging world implies the why anyway, but not specifically. The meaning in this case are for all intents and purposes identical.
Adaptation refers to the general usefulness of evolved traits. If a trait has evolved for its current function, it is an adaptation. If it had originally evolved for a different function, but has been co-opted or modified for current use, it is called an exaptation. Examples of adaptation are numerous; examples of exaptation are the ‘thumb’ of the panda (actually a highly-modified wrist bone, now used to strip bamboo), or the feathers of a bird (thought to have originally evolved for insulation, later becoming the primary flight surface).
Adaptation in a more general sense can also refer to behavioral changes which increase survivability - mavpace’s deer example, and the human examples in the OP, are this sort of adaptation.
This web page gives E.O. Wilson’s definition of adaptation:
Adaptation in this sense is what evolution is all about. If one group of organisms develops adaptations, and another group of organisms of that same species doesn’t, this can be the beginning of speciation.
One other thing to bear in mind is that human beings can also have cultural adaptations. Instead of growing a new anatomical structure, or developing a new hard-wired behavioral pattern, we can learn new behavior patterns. At least some other animals do this too–different populations of chimpanzees have come up with different food-gathering techniques which seem to be learned, not instinctual–but Homo sapiens is the master of cultural adaptation on this planet.
I think you’re thinking of “acclimatization,” which is basically another word for adaptation.