Chapter 52 - Population Ecology

Question 1

•A _______________ is a group of individuals from the same species that live in the same area at the same time.

Answer 1

population

Question 2

•___________________ is the study of how and why the number of individuals in a population changes over time.

Answer 2

Population ecology

Question 3

The mathematical and analytical tools used in population ecology help biologists predict - what?

Answer 3

changes in population size and design management strategies to save threatened species

Question 4

___________ is the study of factors such as these that determine the size and structure of populations through time

Answer 4

Demography

Question 5

To make predictions about the future of a population, biologists need to know - what?

Answer 5

• how many individuals of each age are alive,
• how likely individuals of different ages are to survive to the following year
• how many offspring are produced by females of different ages.

Question 6

•A _____________ summarizes the probability that an individual will survive and reproduce in any given time interval over the course of its lifetime.

Answer 6

life table

Question 7

_______________ is a key component of a life table and is defined as the proportion of offspring produced that survive, on average, to a particular age.

Answer 7

Survivorship

Question 8

•These individuals represent a __________ —a group of the same age that can be followed through time.

Answer 8

cohort

Question 9

•The _______________ is a plot of the logarithm of the number of survivors versus age.

Answer 9

survivorship curve

Question 10

What does a type I curve look like?

Answer 10

survivorship throughout life is high, and most individuals approach the maximum life span of the species; humans show this type of survivorship curve

Question 11

What does a type II survivorship curve look like?

Answer 11

• most individuals experience relatively constant survivorship over their lifetimes; songbirds have this curve.

Question 12

Type III survivorship curve - describe

Answer 12

result from high death rates early in life, with high survivorship after maturity; many plants have type III curves.

Question 13

define fecundity

Answer 13

Fecundity is also a key part of a life table; it is defined as the number of female offspring produced by each female in the population

Question 14

define age specific fecundity

Answer 14

•Age-specific fecundity is the average number of female offspring produced by a female in a given age class—a group of individuals of a specific age.

Question 15

How do you calculate net reproductive rate?

R₀

Answer 15

growth rate of the population over a generation

= ave # of female offspring produced over life @ ea age class

= survivorship * age specific fecundity

Question 16

if the R₀ > 1 what does that mean?

Answer 16

population is growing

Question 17

if R₀ < 1 - what does that mean

Answer 17

pop declining

Question 18

if R₀ = 0

what does that mean

Answer 18

pop stable

Question 19

define fitness trade off

Answer 19

•Fitness trade-offs occur because every individual has a restricted amount of time and energy at its disposal―its resources are limited.

Question 20

What is the difference b/t net reproductive rate R₀ and per capita growth rate r

Answer 20

R₀ is that the growth rate of a population per generation equals the average number of female offspring that each female produces over the course of her lifetime

•The per-capita rate of increase (r) is the difference between the birthrate and death rate per individual.

r = b − d

Question 21

define exponential pop growth

Answer 21

•Exponential population growth occurs when r does not change over time. It does not depend on the number of individuals in the population—it is density independent.

Question 22

under which circumstances is exponential pop growth typically seen?

Answer 22

1. A few individuals found a new population in a new habitat.
2. A population has been devastated by a storm or some other type of catastrophe and then begins to recover, starting with a few surviving individuals.

Question 23

define carrying capacity

Answer 23

•Carrying capacity, K, is the maximum number of individuals in a population that can be supported in a particular habitat over a sustained period of time. K can change depending on conditions.

Question 24

what are the limits on carrying capacity?

Answer 24

• food
• space
• water
• soil quality
• resting or nesting sites.
• Carrying capacity can change from year to year, depending on conditions.

Question 25

define logistic growth equation

Answer 25

•The logistic growth equation describes logistic population growth—a change in growth rate that occurs as a function of population size. * density dependant

Question 26

define metapopulation

Answer 26

If individuals from a species occupy many small patches of habitat so that they form many independent populations, they represent metapopulations―a population of populations

Question 27

R_{0 =}

Answer 27

survivorship \* fecundity

Question 28

density independent factors that affect birth and death rates list

Answer 28

typical of exponential pop growth - ussually abiotic they change birthrates and death rates irrespective of population size. Positive: new habitat overcoming big storm where pop has been wiped out

Question 29

density dependant population growth factors

Answer 29

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

Question 30

describe two examples of density dependent factors that influence pop growth in natural populations

Answer 30

altered by changes in the abiotic enviro food and deer pop density of forest and nutrients and sun abailable 1. coral reef fish - bridled goby - lower density = highter survivorship 2. sparrows - high density = lower eggs laid define particular habitat's carrying capcity