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1

the distribution of populations is limited to

ecologically suitable habitats

2

what are population distributions characterized by

1. range
2. dispersion
3. density
4. abundance
5. dispersal

3

range

geographic distribution of the species

4

dispersion

spatial arrangement of individuals and habitats

5

density

number of individuals per unit of space

6

abundance

size of the population

7

dispersal

patterns of movement of individuals within and among populations

8

spatial structure

the pattern of density and spacing of individuals in a population

9

Fundamental niche

the range of abiotic conditions (e.g., temperature, humidity, salinity) under which a species can persist

10

what may prevent a population from persisting in an area

Competitors, predators, and pathogens

11

realized niche

the range of abiotic and biotic conditions under which a species can persist

12

geographic range

a measure of the total area covered by a population (e.g., temperature and drought define the range of sugar maple)

13

what do small-scale variation in the environment create

geographic ranges that are composed of small patches of suitable habitat

14

Ecological niche modeling

the process of determining the suitable habitat conditions for a species

15

Ecological envelope

the range of ecological conditions that are predicted to be suitable for a species (differs from the realized niche, which describes conditions in which a species currently exists).

16

when is predicting the potential geographic range of a species difficult

when only a few individuals exist

17

what can ecological niche modeling predict

the expansion of pest species

18

Geographic Distribution (Range):

all the areas that a species occupies during
their life time. This might include rivers/ocean

19

Endemic

species that live in a single, often isolated, location

20

Cosmopolitan

species with very large geographic ranges that can span several continents. Cosmopolitan species: rock doves, house sparrows, peregrine falcons, killer whales, cattle egrets

21

Abundance

the total number of individuals in a population that exist within a defined area (e.g., total number of lizards on a mountain).

22

what does the total abundance of a population provide

a measure of whether a population is thriving or on the brink of extinction

23

in a population, the number of individuals per unit area or volume; calculated by dividing abundance by area

density

24

what happens if population density is greater than what the habitat can support

some individuals must leave or the population will experience lower growth and survival

25

where does the largest density of individuals typically occur

near the center of a population's geographic range

26

what happens near the edges of the range

conditions become less ideal and population densities decrease

27

the spacing of individuals with respect to one another within the geographic range of a population

dispersion

28

when individuals are aggregated in discrete groups (e.g., social groups or clustering around resources).

clustered (clumped) dispersion

29

when each individual maintains a uniform distance between itself and its neighbors (e.g., defended territories, croplands).

evenly spaced dispersion

30

when the position of each individual is independent of other individuals; not common due to non-random environmental heterogeneity

random dispersion