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Chapter 8. Population Ecology. Video: Otter Feeding. PLAY VIDEO. POPULATION DYNAMICS AND CARRYING CAPACITY. Most populations live in clumps although other patterns occur based on resource distribution. Figure 8-2. (a) Clumped (elephants). Fig. 8-2a, p. 162. (b) Uniform (creosote bush).
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Chapter 8 Population Ecology
Video: Otter Feeding PLAY VIDEO
POPULATION DYNAMICS AND CARRYING CAPACITY • Most populations live in clumps although other patterns occur based on resource distribution. Figure 8-2
(a) Clumped (elephants) Fig. 8-2a, p. 162
(b) Uniform (creosote bush) Fig. 8-2b, p. 162
(c) Random (dandelions) Fig. 8-2c, p. 162
Animation: Exponential Growth PLAY ANIMATION
Video: Logistic Growth PLAY VIDEO
Exceeding Carrying Capacity: Move, Switch Habits, or Decline in Size • Members of populations which exceed their resources will die unless they adapt or move to an area with more resources. Figure 8-6
Population overshoots carrying capacity Population Crashes Number of reindeer Carrying capacity Year Fig. 8-6, p. 165
Population Density and Population Change: Effects of Crowding • Population density: the number of individuals in a population found in a particular area or volume. • A population’s density can affect how rapidly it can grow or decline. • e.g. biotic factors like disease • Some population control factors are not affected by population density. • e.g. abiotic factors like weather
Types of Population Change Curves in Nature • Population sizes may stay the same, increase, decrease, vary in regular cycles, or change erratically. • Stable: fluctuates slightly above and below carrying capacity. • Irruptive: populations explode and then crash to a more stable level. • Cyclic: populations fluctuate and regular cyclic or boom-and-bust cycles. • Irregular: erratic changes possibly due to chaos or drastic change.
Types of Population Change Curves in Nature • Population sizes often vary in regular cycles when the predator and prey populations are controlled by the scarcity of resources. Figure 8-7
Hare Lynx Population size (thousands) Year Fig. 8-7, p. 166
Animation: Capture-Recapture Method PLAY ANIMATION
Reproductive Patterns:Opportunists and Competitors • Large number of smaller offspring with little parental care (r-selected species). • Fewer, larger offspring with higher invested parental care (K-selected species). Figure 8-9
Reproductive Patterns • r-selected species tend to be opportunists while K-selected species tend to be competitors. Figure 8-10
Late loss Constant loss Percentage surviving (log scale) Early loss Age Fig. 8-11, p. 169
Animation: Life History Patterns PLAY ANIMATION
Video: Coral Spawning PLAY VIDEO
Video: Kelp Forest (Channel Islands) PLAY VIDEO
Video: Salmons Swimming Upstream PLAY VIDEO