Sources: PowerPoint

1. Primary sexual characteristics: reproductive organs
Secondary sexual characteristics: external features of an organism other than reproductive organs that differ between males and females.

2. Sexual dimorphism

3. Ecological selection: Selection for attributes (physical or behavioral) that contribute mostly to survival.
Sexual selection: selection for attributes that contribute mostly to reproductive advantage.

4. Intrasexual selection: within one sex. Usually male-male competition.
Intersexual selection: between sexes. Usually female choice.

5. Direct Fitness Benefits is also called good gene selection because the chooser gains better nest site, territory, provider (of food or protection), parental care, lack of contagious disease or parasites, etc.
Indirect Fitness Benefits is also called runaway selection because the chooser’s offspring gain better sexual attractiveness and viability (not better genes for surviving, but better genes for being chosen as a mate).

6. Mate defense.

7. Resource defense

8. Scramble competition

9. Lek

10. Prenuptial gifts

11. Good looks

12. Single mate per mating season
Pros: two-parent care
Cons: out-reproduced

13. Multiple mates per mating season
Pros: choose best partners
Cons: single parent care

14. Most birds are monogamous and most mammals are polygamous.

15. Polyandry: one female with multiple male mates
Polygyny: one male with multiple female mates
Promiscuity: males and females both have multiple mates.