BIOL 422 Lecture Notes - Lecture 7: Density Dependence, Pollination, Parasitism
5 May 2020
School
Department
Course
Professor
Document Summary
Breeding spaces (e. g. territorial birds take space from each other) Negative density dependence / density dependence / regulation. Birth rate declines or death rate increases with density. Positive density dependence / inverse density dependence / allee effect. Birth rate increase or death rate decreases with density. Species that form groups (i. e. foraging success increases/predation decreases) Imperiled due to human persecution, but not responding despite current protection. Dropping below threshold group size could lead to allee effects. Adults leave babysitters with offspring while hunting; small packs either starve or lose you. Large packs of wild dogs leave babysitters 89% of the time. Small packs (< 5) leave babysitters only 35% of the time. Even ratio at 30 yrs. , 45:55 by 65 yrs. Some behavioural reasons (e. g. homicides are 4m : 1f, suicides higher for men) Smoking/diet deaths (males have 2x higher death rates from lifestyle diseases)
