population dynamics within ecosystems

Question 1

define demography

Answer 1

the name given to the study of vital statistics that effect population size

Question 2

what are the four primary ecological events that determine a population size

Answer 2

1. birth rates 2. death rates 3. immigration rates 4. emigration rates

Question 3

define immigration

Answer 3

the movement of individuals into the population

Question 4

define emigration

Answer 4

the movement of individuals out of the population

Question 5

what is the equation that represents the changes in population size

Answer 5

births + immigrations minus deaths + emigration

Question 6

when will a population grow

Answer 6

when the sum of births and immigration is higher than the deaths and emigration

Question 7

what is exponential growth

Answer 7

when observed, the population’s growth rate rapidly increases over time, such as bacteria grown in a laboratory, when it is reproduced by binary fission

Question 8

what is logistical growth

Answer 8

a more realistic growth model where the population can increase rapidly at first, but then starts to plateau

Question 9

define carrying capacity

Answer 9

the population size at which the curve levels off, which is the maximum population size a particular environment can support

Question 10

define limiting factors

Answer 10

any form of biotic or abiotic factors within an ecosystem that prevent the population from growing any larger

Question 11

what are the limiting factors

Answer 11

amount of food, shelter, number of predators, availability of water, the balance of male and female numbers and the presence of diseases

Question 12

what is a quadrate

Answer 12

a tool used to record the abundance or density of a particular species in a study area

Question 13

what is the quadrate rule

Answer 13

total population is = average number per quadrate x total area being studied, divided by the area of quadrate

Question 14

what is the capture-mark-recapture method

Answer 14

method for estimating animal population sizes that involves capturing, tagging, releasing and recapturing a sample of the animal

Question 15

what are the steps of capture-mark-recapture

Answer 15

1. a sample of species is captured, 2. they are tagged or marked and then released, 3. later another sample of the same size is captured and 4. ecologist count how many are marked to estimate the size of the population

Question 16

what is the capture-mark-recapture rule

Answer 16

population estimated over number of animals captured and marked in the first sample = number of animals captured in the second sample over the number of animals already marked