Origin of Species

From Biol301

What Darwin Said

The big 4: Four requirements for evolution by natural selection

1. There must be variation at a locus
2. The variation must be hertiable
3. There must be a struggle for survival
4. Variants that allow for more offspring become more populous

Answering the 3 Questions

• Why distinct units?
  • The environment varies, so differnt parts of population will develop differently until they are distinct units

• Why distinct hierarchy?
  • Hierarchy is result of the process --things diversify form each other at different times.

• Why a common design?
  • What works once is good enough to work again.