How does descent with modification relate to evolution?
1 Answer
Evolution is not the direct line from one species to another, but the many adaptations transitioning to a very modified descendant
Explanation:
An animal doesn't just make another species. Adaptations occur over time. It's one step and another small step over many generations towards the other animal. There are many animals in-between point A and point B. Large modifications are made of many, many tiny ones. For example, when we say a dog "evolved" from a wolf:
Keeping in mind this occurs over a very, very long time:
The wolf is big and hairy and means business. The next step has to be friendlier wolves. The next step if friendlier wolves that are smaller. The next step has to be friendlier, smaller, less hairy wolves. Each step is a wolf, just modified. Each descendant is just a few changes away from the parent. Over a very long time some of these changes are favored over others. Some of these changes come with gene linkage and other things, like floppy ears or pushed in noses occur. Some adaptations are environmental.
Over a very long time, and enough adaptations, each step makes; Chihuahua! A tiny bald shivery animal that cannot mate and produce a wolf. The wolf did not just wake up in Mexico, lose it's fur get tiny and sit in a designer purse. Many steps made a chihuahua. Many generations adapted to make a new species.
