Population Distribution and Abundance

Question 1

population

Answer 1

a group of individuals of a single species inhibiting a specific area

Question 2

Reasons why ecologists study populations

Answer 2

population holds key information to:

1) saving endangered species
2) controlling pest populations
3) managing fish and game population
4) understanding and controlling disease epidemics

Question 3

Distribution

Answer 3

the size, shape, and location of an area a population occupies

Question 4

Density

Answer 4

the number of individuals per unit area

Question 5

abundance

Answer 5

total number of individuals, or biomass, of a species in a specific area

Question 6

Characteristics of a population

Answer 6

Distribution, Abundance, and density

Question 7

define fundamental and realized niche

Answer 7

fundamental: the physical conditions under which a species might live, in the absence of interactions such as competition.
realized: the actual niche whose distribution is limited by biotic factors such as competition, abundance, growth, survival, reproduction, and distribution of a species.

Question 8

what is tagging used for?

Answer 8

Migration patterns, growth rates, identifying individuals for behavior studies, etc.

Question 9

Examples of methods to assess relative density

Answer 9

Insect pit traps
Pugmark traps
Camera traps
Scented moth traps
Insect light traps
Bait traps 
Fecal pellet counts
Frequency of vocalizations 
Survey questionnaires of people hunting, fishing or 
            living in an area.
Records of catches from professional harvesters

Question 10

Quadrants vs transects

Answer 10

Quadrats/ photoquadrats: random points or simple visual estimation.
Transects: random points along the transect or measuring under the transect.

Question 11

3 types of distribution patterns

Answer 11

random, regular, clumped

Question 12

Random; pattern

Answer 12

Individuals are distributed independently of other organisms of the same species within the environment. equal probability of occurring anywhere in an area

Question 13

Regular; pattern

Answer 13

Individuals are more regularly spaced in the environment than would be expected by chance (more orderly than random). uniformly spaced in an environment.

Question 14

clumped; pattern

Answer 14

Individuals are closer together in groups, with larger gaps separating groups, than would be expected by chance. individuals live in an area of high local abundance, separated by areas of low abundance

Question 15

Random; process

Answer 15

neutral interaction between individuals, and between individuals and the local environment

Question 16

Regular; process

Answer 16

antagonistic interactions between individuals or local depletion of resources

Question 17

Clump; process

Answer 17

the attraction between individuals or attraction of individuals to common resources

Question 18

Pheromones

Answer 18

are chemical substances secreted by some animals for communication with other members of their species.

Question 19

as desert shrubs grow, the population goes from clumped to random to regular, this is because___?

Answer 19

1) seeds germinate at limited numbers of “safe sites”
2) seeds are not dispersed far from the parent plant
3) asexually produced offsprings are necessarily close to the parent plant

Question 20

reasons for changing in the distribution of Creosote bush

Answer 20

Creosote bushes grow in a way to reduce overlapping. Competitive interactions with neighboring shrubs influence the distribution of Creosote bush roots.

Question 21

on large scales, individuals within a population are____?

Answer 21

clumped

Question 22

population density declines with _____ organism size

Answer 22

increasing

Question 23

Habitat tolerance

Answer 23

range of conditions in which a species can live in

Question 24

a classification of commonness and rarity is based on three factors:

Answer 24

1) geographical range
2) habitat tolerance
3) local population size

Question 25

the inverse relationship between size and density is because

Answer 25

of the metabolic requirement of species of larger size.

Question 26

Describe how the age of a population influences its distribution

Answer 26

ll distributions vary with age
example:
*young and small shrubs establish in high densities and produce a clumped distribution
*mortality, as the shrubs grow, reduces clumping and produce a random distribution among medium shrubs
*competition enforces a regular distribution among large shrubs