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Ecology > Chapters 12 and 13: population ecology > Flashcards

Chapters 12 and 13: population ecology Flashcards

1
Q

Population

A

group of individuals from 1 species; live in 1 area at same time

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2
Q

Population ecology

A

study of how and why # of individuals in a population change over time
- Changes in ages of individuals in a population, male/female proportion, geographic distributon

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3
Q

Demography

A

study of factors that determine size and structure of population
- Ex: birth rates, immigration/emigration rates

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4
Q

Population characteristics:

A

natality and mortality

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5
Q

Natality

A

birth rate; # of individuals added through reproduction

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6
Q

Mortality

A

death rate; # of individuals removed through death

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7
Q

Fecundity

A

number of female offspring produced by each female in the population

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8
Q

Immigration

A

when individuals enter a population by moving from another population
- mvmnt in

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9
Q

Emigration

A

when individuals leave a population to join another population
- mvmnt out

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10
Q

2 factors that effect population dynamics

A
  1. Environmental Stress
  2. Changes in Environmental Conditions
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11
Q

what factors limit population growth

A

predation, nutrients, competition, space, resources
- abiotic and biotic factors

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12
Q

population growth equation

A

(change in population) / (change in time)

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13
Q

what factors directly effect population

A

size- # of organisms in population
density- # of individuals/area
dispersion- how organisms are arranged in environment
age distribution- proportion of individuals of each age

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14
Q

Biotic Potential:

A

aka: Inherent reproductive capacity: how many babies a female can have at once
- biotic potential is much above replacement level.
- Natural tendency for increase. No population can increase indefinitely, there are always limits!

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15
Q

Intrinsic Rate of Increase (r)

A

the rate at which a population would grow if it had unlimited resources
- exhibiting high rates of:
- (1) early reproductive age
- (2) short generation times (periods between successive generations)
- (3) long reproductive lives
- (4) lots of offspring

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16
Q

Sex Ratio

A

Relative number of males and females in a population

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17
Q

Age Distribution

A

Number of individuals of each age in the population.
- Greatly influences reproductive rate of a population.

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18
Q

Age Distribution

A

Number of individuals of each age in the population.
- Greatly influences reproductive rate of a population

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19
Q

Age Distribution

A

Number of individuals of each age in the population.
- Greatly influences reproductive rate of a population

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20
Q

expanding age structures

A
  • graph with a wide base and narrow top
  • pyramid graph
  • high pre reproductive ages, less reproductive ages, even less post reproductive ages
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21
Q

stable age structures

A
  • dome/hill shaped graph
  • high pre reproductive ages, high reproductive ages, even more post reproductive ages
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22
Q

declining/diminishing age structures

A
  • dome, restricted at bottom shaped graph
  • low pre reproductive ages, more reproductive ages, less post reproductive ages
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23
Q

Lag Phase (logistical growth curve)

A

First portion of the curve; slow population growth.

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24
Q

Exponential Growth Phase (logistical growth curve)

A

More organisms reproducing causing accelerated growth; continues as long as birth rate exceeds death rate.

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25
Q

Stable Equilibrium Phase (logistical growth curve)

A

Death rate and birth rate equilibrate; population stops growing; achieved in logistical growth curves

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26
Q

Exponential Growth

A

Growth at a constant rate of increase per unit time (Geometric)
- distinct breeding period

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27
Q

Arithmetic Growth

A

Growth at a constant amount per unit time.

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28
Q

Exponential growth occurs when…

A

r does not change over time
- does not depend on the number of individuals
- when increases in the size of a population do not affect r, growth is density independent.

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29
Q

density dependent growth

A

When population density—the number of individuals per unit area—gets very high, we would expect the population’s per- capita birth rate to decrease and the per-capita death rate to increase, causing r to decline.

30
Q

logistical curves have a ___, whereas exponential growth curves do not.

A

maximum carrying capacity

31
Q

Carrying capacity (K)

A

maximum number of individuals in a population that can be supported in a particular habitat over a sustained period of time.

32
Q

Environmental Resistance

A

Any factor (limiting factor) in the environment limiting carrying capacity.

33
Q

four main factors of environmental resistance

A
  1. Raw material availability
  2. Energy availability
  3. Waste accumulation and disposal
  4. Organism interaction
34
Q

density-independent controls

A

affects the population’s size regardless of the population density (independent of # of individuals in a population)
- almost always abiotic
- ex: floods, fires, hurricanes, bad weather, habitat loss, pesticides

35
Q

density-dependent controls

A

limiting factors that are proportional with a populations density (larger population size = worsening effects)
- almost always biotic
- ex: competition for resources, parasitism, predation, disease

36
Q

positive density dependence

A

(+) population growth = (+) population density
- as population grows, density grows
- usually small populations

37
Q

negative density dependence

A

when population reaches carrying capacity; after that it exhibits negative density dependance
- population grows, density decreases

38
Q

equation for time to double population (years)

A

70 / (population growth %) = # years

39
Q

K-strategists have fewer ___, with more ___.

A
  • fewer babies
  • more parental care
40
Q

K-strategists are limited by…

A

density-dependent limiting factors

41
Q

factor(s) that become more severe as the population grow in size?

A

diseases

42
Q

R-strategists are limited by…

A

density independent limiting factors

43
Q

Populations size is irrelevant to the limiting factor ____.

A

weather conditions

44
Q

Zero Population Growth (ZPG)

A

When stability is reached in a population
- mortality=natality
- birth rate = death rate

45
Q

most populations exhibit survivorship curves that combine features of ___ and ____.

A

type I and type III curves

46
Q

K-strategists = type __ curve

A

type I

47
Q

R-strategists = type __ curve

A

type III

48
Q

life table

A

class-specific survival and fecundity data

49
Q

cohort life table

A

life table that follows a group of individuals born at the same time form –> death of last individual (exactly how long organisms born at 1 times are able to survive)
- following age group throughout whole life

50
Q

static life table

A

life table that quantifies survival and fecundity of all individuals in a population during 1 time interval (“aging” dead animals)
- can collect data of how old they are today
- fossils (skulls, bones, etc.)
- dating back organisms found

51
Q

population dynamics

A

changes in populations over time
- patterns of population size fluctuations over time

52
Q

population fluctuations due to…

A

factors such as availability of resources, predation, competition, disease, parasites, and climate
- Fluctuations include random and cyclic changes through time

53
Q

Cyclic populations

A

occur among related species and across large geographic areas

54
Q

age structure fluctuations

A
  • if an age group contains a high or low number of individuals, the population likely experienced high birth or death rates in the past
55
Q

Overshoot

A

when a population grows beyond its carrying capacity
- often occurs when the carrying capacity of a habitat decreases from one year to next
- ex: because less resources are produced

56
Q

Die-off

A

a substantial decline in density that typically goes well below the carrying capacity

57
Q

Die-offs often occur when….

A

a population overshoots its carrying capacity

58
Q

___ populations are more vulnerable to extinction than __ populations.

A
  • small populations >
  • larger populations
59
Q

stochastic model

A

a model that incorporates random variation in population growth rate; assumes that variation in birth and death rates is due to random chance

60
Q

deterministic model

A

a model that is designed to predict a result without accounting for random variation in population growth rate

61
Q

Demographic stochasticity

A

variation in birth rates and death rates due to random differences among individuals

62
Q

Environmental stochasticity

A

variation in birth rates and death rates due to random changes in the environmental conditions (ex: changes in the weather)

63
Q

Habitat fragmentation

A

the process of breaking up large habitats into a number of smaller habitats

64
Q

sources

A

high-quality patches that produce a large number of individuals that disperse to other patches

65
Q

Sinks

A

low-quality patches that produce few individuals and rely on dispersers to keep the sink population from going extinct

66
Q

_____ patches that are close to ____ patches are more likely to be colonized.

A
  • unoccupied
  • occupied
67
Q

Rescue effect

A

when dispersers supplement a declining subpopulation and thereby prevent it from going extinct

68
Q

uses of meta population theory

A
  • reintroducing species resistant to extinction
69
Q

population viability analysis (PVA)

A
  • a model that estimates the likelihood that a population will avoid extinction for a given time period
  • attempts to combine basic demographic models with data on geographic structure and the rate and severity of habitat disturbance
70
Q

Basic model of metapopulations (p =)

A

proportion of occupied patches when colonization and extinction have reached an equilibrium

71
Q

geometric growth =

A

exponential growth

72
Q

logistical growth model

A

a growth model that describes slowing growth of populations at high densities

Ecology (33 decks)

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