Chapter 11: Population Growth and Regulation

Question 1

Four Processes that influence populations

Answer 1

birth, death, immigration, and emigration

Question 2

Population increases by a constant proportion

Answer 2

geometric growth and exponential growth

Question 3

Geometric Growth

Answer 3

organisms reproduce in synchrony at discrete time periods
-the number of individuals added is larder with each time period, and the population grows larger by ever-increasing amounts
-results in a j-shaped set of points

Question 4

Exponential Growth

Answer 4

organisms reproduce continuously over time
-results in a j shaped curve

Question 5

Go look at slides 18 and 19 in Chapter 11

Question 6

Doubling Time

Answer 6

number of years it will take a population to double in size

Question 7

How do populations increase (addition or multiplication)?

Answer 7

multiplication

Question 8

What type of factors change population size and growth rate over time?

Answer 8

-density independent factors and density dependent factors

Question 9

Density-Independent Factors

Answer 9

-their effects on population size or growth rate are independent of the numbers of the individuals in the population
-weather conditions, catastrophes, climate change

Question 10

Density-Dependent Factors

Answer 10

-their effects are dependent on the number of individuals in the population
-amount of resources such as food or habitat influence population size

Question 11

How does gradual climate change impact populations

Answer 11

-increasing mortality rates in western coniferous forests over several decades is related to regional warming
-higher temps have led to less snowpack, earlier spring melt, and longer dry summers
-caused an increase in the tree’s climactic water deficit (amount by which a plant’s annual evaporative demand for water exceeds available water)

Question 12

As population density increases…

Answer 12

birth rates often decrease, death rates increase, and dispersal (emigration) increases, all decrease population size

Question 13

Population Regulation

Answer 13

density-dependent factors cause population to increase when density is low and decrease when density is high

Question 14

Do density-independent factors regulate population size?

Answer 14

NO. Only density-dependent factors can regulate

Question 15

Logistic Growth

Answer 15

population increases rapidly, then stabilizes at carrying capacity

Question 16

What causes growth rate to slow as a population reaches carrying capacity?

Answer 16

resources begin to run short

Question 17

What is the growth rate of a population at carrying capacity?

Answer 17

growth rate is zero

Question 18

Who derived the logistic equation and predicted carrying capacity for the US population?

Answer 18

Pearl and Reed (1920)

Question 19

Ecological Footprint

Answer 19

the total area required to support a human population

Question 20

Life Table

Answer 20

summary of how survival and reproductive rates vary with age, size, or life stage of individuals

Question 21

How are life tables used?

Answer 21

to predict future population trends and develop strategies for managing populations

Question 22

Age Class

Answer 22

members of a population whose ages fall within a specified range

Question 23

Age Structure

Answer 23

proportion of a population in each age class; influences whether population will increase or decrease in size

Question 24

How does age structure affect population?

Answer 24

-if there are man people of reproductive age, it will grow rapidly
-a population with many older, it will grow slowly
-rapidly growing human populations have a greater percentage of people in younger age classes

Question 25

Type I Survivorship Curves

Answer 25

most individuals survive to old age

Question 26

Type II Survivorship Curve

Answer 26

chance of surviving remains constant throughout the lifetime

Question 27

Type III Survivorship Curves

Answer 27

high death rates for young; those that reach adulthood survive well (species that produce a lot of offspring)

Question 28

Survivorship curves can vary:

Answer 28

-among populations of a species
-between males and females
-among cohorts that experience different environmental conditions. The edicts of those conditions on populations can be assessed

Question 29

Cohort Life Table

Answer 29

follows the fate of a group of individuals all born at the same time (cohort)

Question 30

What are cohort life tables mostly used for?

Answer 30

mostly used for sessile organisms. organisms that are highly mobile or have long life spans are difficult to track

Question 31

Look at slide 58-60 on Chapter 11

Question 32

Generation Time

Answer 32

average age of parents of all offspring produced by the cohort

Question 33

Static Life Table

Answer 33

survival and reproduction of individuals of different ages during a single time period

Question 34

What are static life tables used for?

Answer 34

mobile organisms or ones with long life spans’ requires age estimation

Question 35

Method to manage populations

Answer 35

identify the age-specific birth or death rates that most strongly influence population growth rate