Generally, we group animals by whether or not they can successfully breed together (Although we don’t always get this right). But surely, there is always natural variation and constant changes to the DNA of a group of animals. So whenever a group becomes divided geographically, the two groups will become more and more different over time. We see this happening all the time in nature, take these skinks for example: http://www.newscientist.com/article/dn19366-zoologger-live-birth-evolving-before-our-eyes.html
If this happens and we ‘know’ that it happens, then why would you not expect these differences to become pronounced over very long periods of time? So that eventually, if the two groups were brought back together, they would no longer be able to successfully breed.
The problem is, changes this large take a long time occur… and usually require some kind of environmental change or upheaval to kill off some of the group, thereby removing the genes that one group shares with the other. Obviously sudden localised environmental changes like this, happen a lot in nature, but not so much that humans could really study and observe them on any kind of meaningful timescale. All we can do, is look at the end result and notice that the animals DNA clearly shows that they are related.
Getting back to my original point, I think that the obsession with the idea of species, is one of the reasons why people find evolution so hard to grasp… The word ‘evolution’ conjures the image of one animal changing into another, which is incorrect.
A better way to see it, is a large group of varied animals being separated and whittled down by death, breeding then being whittled down again and again, until the similarity between them is no longer as obvious as it once was. Nature doesn’t really deal with ‘species’ at all, it is just one long process of life, death and little changes.
We are the ones who stepped back, looked at all the creatures… and started giving them names.
Interesting question! Check out these two articles on the Answers in Genesis website about the field of baraminology and the categorizing of animal kinds and how they might be different from species as we know them. For example, lions and tigers are considered by many to be different species within the feline genus, but they can mate and produce offspring. Some species were grouped together based on appearance, behavior, &:c.: now, we can do genetic studies to use for grouping, which baraminology takes into account.
Classification is far from arbitrary.
That does not preclude error, of course.
You may as well ask is water and wine the same thing?
We give ourselves genders too. Humans have an inherent need to classify. Just like… what is it… RELIGION!!!
":Species": are ofcourse made up by men.
In the end we’re all the same, we just took another form.
A human classification, without a doubt.
But, of course, so is gender.
I digress – sorry.
Have you ever heard of genetics?
Man, that is deep!
yes but wrong forum….ANIMALS DON’T NEED relig.