Chapter 11 Infraspecific Population Regulation

Question 1

Density Dependent Population Regulation

Answer 1

how higher densities naturally lead to less births (decreasing fecundity) and more deaths (increasing mortality), leads the populations to slow the rate of population growth

Question 2

Carrying Capacity (K)

Answer 2

maximum sustainable population size for the prevailing environment

Question 3

Logistic model of population growth (dN/dt = rN (1 - N/K))… implications of K? where is growth maximized?

Answer 3

• maximizes growth rate of population at HALF the carrying capacity size (K/2)
• at K, population growth is 0

Question 4

Competition

Answer 4

-OCCURS WHEN INDIVIDUALS USE A COMMON RESOURCE THAT IS IN SHORT SUPPLY RELATIVE TO THE NUMBER SEAKING IT

Question 5

Scramble Competition

Answer 5

when growth and reproduction are depressed . equally across individuals in a population as the intensity of the competition increases… !!!!!!!!not any advantages for some individuals over others!!

Question 6

Content Competition

Answer 6

when some individuals claim enough resources while denying others a share… some successful individuals do better than others

Question 7

Exploitation competition

Answer 7

individuals don’t interact with one another… zebras eating the grass in the savanna don’t directly influence eachother but end up overgrazing and causing less grass to be available for other individuals

Question 8

Interference Competition

Answer 8

denying other individuals access to the site and its resources (LIKE A BIRD DEFENDING ITS NEST DURING BREEDING SEASON)

Question 9

Density independent factors meaning

Answer 9

natural influences… like a drought or excessive flooding

Question 10

Density dependent growth meaning

Answer 10

inverse relationship between population density and growth… MORE DENSITY, LESS GROWTH

Question 11

Influence of competition on growth

Answer 11

Less growth if more competition

Question 12

Influence of competition on mortality rates/ survival rates

Answer 12

competition reduces survivial rates/ increases mortality rates

Question 13

self thinning

Answer 13

progressive decline in density and increase in biomass of remaining individuals caused by combined effects of density dependent mortality and growth within a apopulation…. AS POPULATION STARTS TO DECREASE, SIZE OF REMAINING INDIVIDUALS GOES UP… something like this

Question 14

Competition impact on reproduction

Answer 14

REDUCES REPRODUCTION… REDUCES FEDUNCITY… less resources for the population, less mass per individual, less babies for smaller animals

Question 15

Home range

Answer 15

area that an animal normally uses during a year

Question 16

How home range varies as a function of body size or trophnic group?

Answer 16

• carnivores require a larger home range than herbivores and omnivores of the same size
• bigger the body size, bigger the home range needs to be

Question 17

Territory

Answer 17

home range that is defended by an animal

Question 18

When there is an EXCESS of males and females of reproductive age unable to establish breeding territories…

Answer 18

the act of having territories would act as a density dependent regulator as reproduction would be limited.. but only if there is nowhere to have territory!

Question 19

Allee Effect

Answer 19

density dependent mechanism have also been identified that function to reduce birth and survival rates of populations with LOW DENSITIES

Question 20

Some examples of allee effect:

Answer 20

• organisms having too small pop densities in an area nd thus not being able to reproduce decreasing birth rates
• when a population is too small to sustain an effective herd or pack, the population may decline from increased mortality because of predation or starvation