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Biology 101 > Population Ecology > Flashcards

Flashcards in Population Ecology Deck (79):
1

describes where individuals of a species might potentially be located.

(In the United states, most species have a range of 4-24 states.)

Geographic Range

2

These species are an extreme, they are worldwide in distribution.

Cosmopolitan

3

species found in only a small, restricted area, they represent the other side of the spectrum.

Endemic

4

Factors Determining the Geographic Range of a Species

History
Biological Tolerances
Other Species
A combination of the above

5

Why can't palm trees present where winter temperatures regularly go below freezing?

The meristems are at the top of the trunk, not tolerant of freezing

6

What other reasons explain why palm trees are near beaches and in micronenvironments?

They compete well in moist environments. Seeds are water dispersed.

7

Many species have what is called a “Gondwanan” distribution. They occur in the Southern continents of Australia, South Africa, South America, and sometimes India.
These places are far away from each other now, but 150 million years ago, they were all linked together in a massive continent.

What is this an example of?

Historical Factors Determining Geographic Range

8

Populations arise when....

Discontinuities in suitable habit for a species restricts the movement of individuals

9

consequences of the way an organism interacts with the environment, and with other organisms, and influence its evolution

Emergent properties

10

Simply the number of individuals in the population at any given time. Sometimes called abundance.

Size

11

The number of individuals in the population per unit area or unit volume.
For many organisms this measure, rather than its actual numbers, exerts a real effect on the organism.

Density

12

Patterns of Dispersion

Clumped
Regular
Random

13

The most common pattern of dispersion, occurs because some areas of habitat are more suitable than others
ex:salamanders in numbers under fallen logs

Clumping

14

Why do plants often clump?

Because seeds fall close to parent plant

15

What are other reasons why a species may clump?

Safety of social reasons

16

This pattern occurs in the absence of strong attraction or repulsion among individuals.
It is uncommon.

Random Distribution

17

This generally happens because of interactions between individuals in the population, like competition, territoriality, and human intervention

Regular Distribution

18

Creosote bushes in the Mojave desert are uniformly distributed because competition for water among the root systems of different plants prohibits the establishment of individuals that are too close to others.

Competition

19

The desert lizard Uta sp. maintains somewhat regular distribution via fighting and territorial behavior

Territoriality

20

I.e. ., the spacing of crops

Human Intervention

21

This is the relative number of individuals at different ages

Age Structure

22

is the proportion of individuals of each sex. The number of females is more important in the overall growth rate of populations
Examples: elk; fewer males of reproductive age than females; males breed with more than one female.

Sex Ratio

23

differences among individuals in the population

Variability

24

Most populations show differences among individuals.
Some variation has a genetic basis.
Other variation is largely environmental.
In many cases, variability is caused by both genes and the environment

Word

25

Variability that occurs when the two sexes differ greatly in appearance

Sexual Dimorphism

26

Variability that occurs when individuals differ in appearnace because of a dramatic transformation as they age

Metamorphisis

27

Many organisms that exist as interwoven collections of subpopulations

metapopulations

28

exhibit their own dynamics, with localized extinction, and recolonization of unoccupied areas of suitable habitat, determining their dynamics.

Metapopulations

29

This is probably the best, simple, model of population growth…it predicts the rate of growth, or decay, of any population where the per capita rates of growth and death are constant over time

Exponential Growth

30

Formula for exponential growth

Nf = Ni(e^rt)

31

Can a population continue growing forever?

No, they would outstrip their resources

32

this is the maximum number of individuals a given environment can sustain.

Carrying capacity

33

Resources that are rare enough to inhibit a species' reproduction so that the population no longer grows.
ex) light, water, nesting sites, prey, nutrients

Limiting Resources

34

Factor limiting populations that intensifies as the size of a population increases

Density-Dependent Factor

35

Examples of this factor that limits populations includes suitable nesting sites for birds, competition for light and water amongst prairie grasses

Density Dependent Factor

36

Factors limiting populations that are independent of population size

Density-Independent Factors

37

Examples of this factor that limits populations includes winter temperatures

Density-Independent Factors

38

growth model that accounts for carrying capacity

Logistic growth model

39

Formula for logistical growth model

dN/dt= rmax*N(K-N)/K

NOTE: when k =n, dN/dT is equal to zero
When it is small, growth rate is approximately rmax
When N>K, population declines

40

Does logistical growth model fit actual populations?

Only lab populations, not actual populations due to other factors like lag time.

41

The time it takes between reaching carrying capacity and the slowdown in reproduction

Rapidly growing populations, or populations with lag time often overshoot K, and exhibit population cycles, or chaotic behavior

Lag Time

42

the study of the age structure and growth of populations. It is, essentially, the study of birth, reproduction, and death, as it relates to populations.

Demography

43

was a famous early demographer/economist.
In his Essay on the Principal of population, 1798, he was the first to reach the conclusion that human populations tended to grow until they outstripped their available food supply.

Thomas Malthus

44

count every individual in the population

complete enumeration

45

count individuals in many small portions of the area (e.g., quadrats) then calculate density
mark and recapture
index of relative abundance (e.g., pheremone baited insect traps, camera traps)

Sample the population

46

A person’s chance of death

Life Tables

47

a group of organisms born at the same time.

Cohort

48

The variable that can estimate population growth or decline using life tables

the sum of l(x)m(x) for the entire lifespan, estimates the number of female offspring produced per female.

R0

49

R0>1, R0<0, R0=1

Increase, decline, stable

50

traces the decline of a group of newborns over time.

Survivorship curves

51

plot the probability of surviving to a certain age for a representative member of the population.
They sometimes differ from male vs. female.
Different populations might have different

Survivorship curves

52

A convex curve. Most individuals live to adulthood with most mortality occurring during old age. I.e., humans, red deer, elephants.

Type I

53

A straight line. An individual’s chance of dying is independent of its age. I.e., small birds and mammals.

Type II

54

A concave curve, few individuals live to adulthood, with the chance of dying decreasing with age. I.e., oysters, redwood trees, snapping turtles.

Type III

55

is the proportion of individuals at different ages.
It has a significant impact on future population growth.

Age distribution

56

Populations that have remained constant for a long time have what type of age distributions?

Stable

57

Rapidly growing populations have a disproportionate number of young individuals.

True

58

many older people, fewer young people. Populations of some countries will decrease in the future.

Europeans and Japanese

59

many young people, fewer old people populations will increase in the future.

Africa, Near east

60

When is m(x), or age specific fecundity highest in humans?

20 yr olds.

61

When are death rates highest?

Babies and old age.

62

Are death rates in U.S. higher or lower than guatemala, mexico, and most of developing world?

Higher

63

the timing of an organisms reproduction and death

Life history

64

how many offspring an organism produces that are ultimately able to produce their own offspring.

Fitness

65

Why is there a trade-off between survivorship and reproduction?

Reproduction is dangerous, involves resources for growth/maintenance

66

Life histories have evolved to maximize an organisms expected fitness

Ya

67

is one large reproductive effort (most insects, annual plants). Examples, grasshoppers, mayflies, octupi and squids Agave.

Semelparity

68

is fewer offspring and many reproductive episodes. Example, perennial plants, most large mammals, sharks, most birds such as gulls and terns.

Iteroparity

69

the number of offspring produced per reproductive episode.

Clutch size

70

expend all their resources on a single clutch.

Semelparous organisms

71

must save some resources for growth and survival.

Iteroparity

72

Clutch size varies depending on...

Resource availability

73

As an organism ages, it has more resources available to it. So more resources later means?

More offspring.

74

Reproduce earlier means?

Less offspring.

75

Larger organisms reach reproductive age faster or slower?

Slower

76

an adaptation by which an organism may potentially increase the survivorship of its offspring.
It comes at a cost to the parents, however, and results in fewer offspring because resources must be conserved

Parental Care

77

Birds providing varying or similar amounts of parental care?

Varying.

78

hatch and are able to fend for themselves immediately. Eggs are often laid in warm environments, and parents do not incubate them. In theory, this means more time to forage .

Superprecocial Birds

79

such as passerines and parrots. Young are born blind and require constant parental care, after a period of egg incubation.

Superaltrical birds.