chapter 13 Flashcards Preview

ecology > chapter 13 > Flashcards

Flashcards in chapter 13 Deck (31)
Loading flashcards...
1

All populations experience fluctuations due to

availability of resources, predation, competition, disease, parasites, and climate.

2

what allows larger organisms to maintain homeostasis in the face of unfavorable environmental changes.

Larger organisms have a lower surface-area-to-volume ratio

3

What can the age structure of a population tell us about pop. fluctuations over time?

It can show times of particular growth or decline in previous years.

4

When an age group contains a high or low number of individuals, the population likely experienced

high birth or death rates in the past.

5

when a population grows beyond its carrying capacity; often occurs when the carrying capacity of a habitat decreases from one year to next (e.g., because less resources are produced).

Overshoot

6

a substantial decline in density that typically goes well below the carrying capacity.

Die-off

7

regular oscillation of a population over a longer period of time.

Population cycles

8

Cyclic populations can occur among

related species and across large geographic areas

9

Populations are stable at their

carrying capacity

10

Why are some pops. inherently cyclical?

There is a delay between the time of breeding and the birth of offspring.

11

when density dependence occurs based on a population density at some time in the past.

Delayed density dependence

12

r =

intrinsic growth rate

13

N =

current population size at time t

14

K =

carrying capacity

15

dn
____=
dt

rate of change in population size

16

How can energy reserves make a pop. experience delayed density dependence?

They enable the population to survive above carrying capacity.

17

Delayed density dependence may occur because the

organism can store energy and nutrient reserves.

18

When populations are low and food is abundant, the water flea Daphnia galeata stores surplus energy as lipid droplets.
is an example of

Delayed density dependence

19

Delayed density dependence can occur when there is a

time delay in development from one life stage to another.

20

Small populations are more vulnerable to extinction

than larger populations.

21

Which is an example of demographic stochasticity?

low fertility for some individuals

22

variation in birth rates and death rates due to random differences among individuals

Demographic stochasticity

23

variation in birth rates and death rates due to random changes in the environmental conditions

Environmental stochasticity

24

the process of breaking up large habitats into a number of smaller habitats.

Habitat fragmentation

25

high-quality patches that produce a large number of individuals that disperse to other patches

Sources

26

low-quality patches that produce few individuals and rely on dispersers to keep the sink population from going extinct.

Sinks

27

We can increase the number of occupied habitat patches by providing

corridors between patches to increase the rate of colonization (c).

28

We can also increase the number of occupied patches by

decreasing rates of extinction (e).

29

Dispersal success is inversely related to

the distance of dispersal;

30

refers to the dispersal between source and sink populations.

) The rescue effect