Populations

Question 1

what stops a population from rising above a certain level?

Answer 1

limiting factors

Question 2

limiting factor definition

Answer 2

an environmental resource or constraint that limits population growth

Question 3

what is used to show the growth of a population

Answer 3

a population growth curve

Question 4

3 main phases of population growth curve

Answer 4

• phase 1 , slow growth
• phase 2 , rapid growth
• phase 3 , a stable state/ stationary phase

Question 5

name and explain Phase 1

Answer 5

small numbers if individuals that are present reproduce, and because the birth rate is higher than the death rate, the population increases in size.

Question 6

name and explain phase 2

Answer 6

in rapid growth, the number of breeding individuals increases, so the total population grows exponentially. no constraints limit population growth yet.

Question 7

name and explain phase 3

Answer 7

in a stable state, further population growth is limited by external constraints. population size fluctuates but remains stable. birth and death rates are equal.

Question 8

what accounts for fluctuations in population size during the stable state

Answer 8

• limiting factors such as the presence of predators

Question 9

name the two categories of limiting factors

Answer 9

abiotic factors
biotic factors

Question 10

define density dependant factors

Answer 10

limiting factors that are caused by a populations abundant size (disease, competition, build up of toxic byrproducts from metabolism)

Question 11

define density independent factors

Answer 11

limiting factors that affect the population regardless of size (natural disasters)

Question 12

what other names are used for the slow and rapid growth phases on the population curve?

Answer 12

LAG and LOG phases respectively

Question 13

carrying capacity

Answer 13

the maximum stable population an ecosystem can hold

Question 14

logarithmic scales

Answer 14

increments on this scale increase quickly by large numbers

Question 15

what limiting biotic factors might affect abundance

Answer 15

• competition (inter and intra specific)
• predators
• disease

Question 16

biotic factor that affects population abundance, not a limiting factor

Answer 16

migration ( immigration into a population, emigration away from a population)

Question 17

what abiotic limiting factors might affect population abundance

Answer 17

• nesting sites
• light
• availability of water and oxygen
• pH

Question 18

What abiotic factors might affect distribution

Answer 18

• soil and water pH
• temperature
• sunlight
• water availability
• altitude

Question 19

what biotic factors may affect distribution?

Answer 19

• predation
• interspecific competition because it leads to the reduction of a resource that multiple species are fighting for.

Question 20

interspecific competition

Answer 20

competition between different species

Question 21

intraspecific competition

Answer 21

competition between members of the same species

Question 22

explain outcompetition

Answer 22

when in interspecific competition, one organism is better adapted and therefore the other species will decline.

Question 23

explain competitive exclusion principle

Answer 23

the less well adapted species will continue to decline until it can no longer exist in the habitat with the better adapted species. the better adapted organism will effectively eliminate the other.

Question 24

intraspecific competition leads to

Answer 24

fluctuations of the number of organisms present in a given time

Question 25

How many stages are in intraspecific competition?

Answer 25

3

Question 26

intraspecific competition stage 1

Answer 26

resource is plentiful, population abundance increases

Question 27

intraspecific competition stage 2

Answer 27

larger population means less food and space available. not enough resources for sll organisms to survive, population decrease.

Question 28

intraspecific competition stage 3

Answer 28

less competition due to fewer organisms competing for the same resources, population grows

Question 29

when an organism kills and eats another

Answer 29

predation

Question 30

predation is a type of..

Answer 30

interspecific competition

Question 31

stage 1 of predator-prey relationship graph

Answer 31

increase in prey, more food for predators, increase in predators

Question 32

stage 2 of predator-prey relationship graph

Answer 32

more predators means less pray
birth rate of prey population is lower than death rate

Question 33

stage 3 of predator-prey relationship graph

Answer 33

reduced prey population can no longer support increased predator population. predator abundance decreases

Question 34

stage 4 of predator-prey relationship graph

Answer 34

reduced predators, less of prey being killed, more of prey. cycle begins again.

Question 35

what other factors affect the predator prey relationship?

Answer 35

availability of plants, presence of other predators

Question 36

How does interspecific competition (biotic) affect population size?

Answer 36

fewer resources available for both populations. Both populations reduce in size.

Question 37

How can the variability of temperature affect population size?

Answer 37

When the temperature is significantly lower/higher than organism’s optimum temperature, mammals have to use up enrgy to maintian body temperature, so less energy is available for growth and reproduction. Population size decreases.

Question 38

Population size

Answer 38

Total number of organisms of one species in a habitat