The baseline

Evolution proceeds through changes in the DNA, which give rise to somatic differences.
Changes are kept if Nature permits.
Change lead to adaptation, and to survival.
Nature optimizes
- But it does so locally, temporally and geographically.

You can't use a platypus to take loads across the desert, or a camel to, well, puzzle people and think it's a hoax

Evolution proceeds through changes in the DNA, which give rise to somatic differences.