BIOL 3300 Lecture Notes - Bighorn Sheep, Sexual Selection, Female Promiscuity
Document Summary
Dimorphisms where males and females look different. Widow birds: females are brown and quiet, males are more colorful and have a long tail. Collared lizards: male are more brightly colored and have higher predation rates, females are able to blend nicely into the rocks. Ecological selection: caused by the environment; differential reproductive success due to individual variation in survival and reproductive output (excluding mating success) Acts on individuals and gametes: motility of sperm. If an individual sperm is able to move faster than the others it will be able to get to the egg first and fertilize it. Intrasexual selection: competition between two males or two females. Ex: big horn sheep fighting for the females. Intersexual: selection via mate choice, usually non-random mate choice by females. Caring for young, feeding the young, protecting them, incubating eggs. Limits on reproductive success: limit as to how many eggs or sperm an individual can produce, may be tradeoffs as to how big.
