BIO 109 Online Home
Lab Manual
Natural History Event Species List


Sources: PowerPoint 03e and 03f, Web, text (p. 459-507)

1. hair and mammary glands

2. Monotremes: lay eggs
Marsupials: give birth to embryonic young
Placental Mammals: retain fetus in uterus for full term and use true placenta to supply nutrients and rid wastes.

3. Rodents first and bats second.

4. Antlers: made of bone, shed annually, only males have them (except in caribou where both sexes have them. Deer have antlers.
Horns: made of bone core and keratin sheath, never shed, both sexes have them. Bighorn sheep have horns.
Pronghorns: made of bone core and keratin sheath, the keratin sheath is shed annually, both sexes have them. Only the pronghorn have pronghorns.

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

6. Sexual dimorphism

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

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

9. 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).

10. Mate defense.

11. Resource defense

12. Scramble competition

13. Lek

14. Prenuptial gifts

15. Good looks

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

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

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

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

20. Moths (and some other insects) have developed the ability to hear bat ultrasonic chirps. They use two sensory fibers in their "ears." The A1 fiber hears the bat from a long way off (before the bat detects the moth) and the moth reacts by flying away from the bat. The A2 fiber hears the bat only at the last second, when the bat is very close, and the moth reacts by reflexively altering course which reduces predation by 40%.