Species are set by who breeds with whom
- The idea
- Predict
- See it
- Why
- Check
The idea
“Looks and location decide whether two groups are one species.”
Field guides sort animals by looks, and neighbors seem like one kind. Both are only clues.
The short version
The mistake: Looks and location decide whether two groups are one species.
What's actually true: Under the biological species concept, groups that can interbreed in nature and have fertile offspring are one species.
- Under the biological species concept, a species is a group whose members can interbreed in nature and have fertile offspring.
- Prezygotic barriers act before fertilization, like different mating seasons, songs or habitats. Postzygotic ones act after, like hybrids that die young or are sterile.
- The interbreeding test can't be used on fossils or asexual organisms, so biologists use form or DNA for those.
On the exam: Ask whether they interbreed and leave fertile offspring.