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Biology 1306 > 53: Population Ecology > Flashcards

53: Population Ecology Flashcards

1
Q

what affects the size of a population and how it changes over time

A

adding or removing individuals

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2
Q

what can be used to describe population

A

its boundaries and size

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3
Q

what is a boundary

A

it can be natural like an island or lake

or arbitrarily defined by an investigator

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4
Q

what is population ecology

A

explores how biotic and abiotic factors affect population, density, dispersion and demographics

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5
Q

what is density

A

the number of individuals per unit area or volume

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6
Q

what is dispersion

A

pattern of spacing among indiviudals within the boundaries of the population

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7
Q

what is demography

A

study of birth/death/migration rates

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8
Q

what can be used to find density

A

sampling techniques like the mark-recapture method

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9
Q

how do they use the mark-recapture method

A

scientists capture and tag random sample of individuals in a population and they are given back to the population then they capture a second sample and note how many they mark

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10
Q

what is the formula to solve for population size

A

x/n= s/N or N=sn/x

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11
Q

what is density the result of

A

processes that add individuals and remove individuals

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12
Q

what is immigration

A

influx of new individuals and births to increase population size

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13
Q

what is emigration

A

movement of indivduals out of a population, and deaths to decrease population size

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14
Q

what is the pattern of dispersion determined by

A

spacing among individuals within the boundaries

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15
Q

what factors affect the spacing of individuals in a population

A

environmental and social factors

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16
Q

what is the most common pattern of dispersion

A

clumped

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17
Q

what is a clumped pattern

A
  • individuals aggregate in patches

- aggregate in high resource availability or favorable physical conditions

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18
Q

what else can influence the clumped pattern

A

mating behavior and group predation or defense

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19
Q

what is uniform dispersion

A

individuals spread out evenly

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20
Q

in uniform dispersion what do plants do

A

secrete chemicals that inhibit germination and growth of competing individuals

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21
Q

what is uniform dispersion influenced by

A

social interactions like territory and the defense of a bounded space against other individuals

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22
Q

what is random dispersion

A

the position of each individuals is independent of other individuals

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23
Q

when does random dispersion occur

A

occurs in the absence of strong attractions or repulsions among individuals

24
Q

what is demography

A

study of the vital statistics of population

25
Q

what is a life table

A

age-specific summary of the survival and reproductive rates

26
Q

what is the fate of a cohort on the life tables

A

a group of individuals of the same age

27
Q

what group is ignored in a life table

A

males because only females produce offspring

28
Q

what does a life table show

A

proportions of females alive at each age and the number of female offspring produced per female

29
Q

what is survivorship curve

A

graphic way of representing the data in a life table

30
Q

what are the general types of survivorship curves

A

type 1
type 2
type 3

31
Q

type 1 curve

A

low death rates in early and middle

increase in death rates among older age groups

32
Q

type 2 curve

A

constant death rate over organisms life span

33
Q

type 3 curve

A

high death reates for the young and lower death rate for survivors

34
Q

what can be used to estimate the number of breeding females

A

direct counts, mark-recapture, molecular tools

35
Q

what is an exponential model

A

describes population growth in an idealized unlimited environment

36
Q

population growth for an exponential model

A 
dN/dt = rN
r = per capita change
dN/dt = very small changes in population size over short
37
Q

what are some characteristcs of a J-shaped curve

A

rate of increase is constant
large populations grow faster than small populations
- larger r grows faster
-smaller r = grows slower

38
Q

what does the logistics model describe

A

describes how a population grows more slowly as it nears its carrying capacity

39
Q

wha is carrying capacity

A

the max pop size that an enviornment can sustain

40
Q

what are some characteristics of the logistics population growth model

A
  • starts with exponential growth model
  • adds (K) carrying capacity
  • k reduces per capita
  • new individuals are added to the population most rapidly at intermediate population sizes
  • population growth decrease as N approaches K
41
Q

what is the logistics pop formula

A

dn/dt = rn(K-N)/k

42
Q

what shape does a logistics growth model represent

A

sigmoid(s shape)

-

43
Q

what is the logistics model used for

A

predicting the rate of recovery for small populations

  • estimating the sustainable harvest rates for wildlife
  • estimating the critical size
44
Q

what is the life history?

A

traits that affect the schedule of reproduction and survival

45
Q

what does life history reflect

A

the development, physiology and behavior of an organism

46
Q

what does life-history entail

A

the age, how often they reproduce, how many offspring are produced

47
Q

what is semelparity

A

reproduce once or big band reproduction then die

48
Q

what is iteroparity

A

repeated reproductive events

49
Q

what influences trade-offs

A

selective pressures influence the number and size of offspring

50
Q

what do species do when they have young who don’t have a long life span

A

produce many small offspring

51
Q

plants produce a large number of small seeds

A

ensure that at least some of them will grow and eventually reproduce

52
Q

why do parents produce few offspring

A

invest more energy in each offspring to increase the probability of survival for each

53
Q

what is density-dependent birth and death rates

A

example of negative feedback that regulates population growth

54
Q

what affects density-dependent birth and death rates

A

competition for resources, disease, predation, territoriality, toxic wastes, and intrinsic factors

55
Q

what is the intrinsic factor

A

the genetic, physiological, and pathological characteristics of an individual

Biology 1306 (15 decks)

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