Population Growth and Regulation

Question 1

demography

Answer 1

the study of the structure and growth of populations

Question 2

2 models of population growth

Answer 2

geometric and exponential

Question 3

geometric growth model

Answer 3

has discrete time intervals
- seasonal patterns of reproduction

Question 4

exponential growth

Answer 4

has time treated as continuous
-species overlapping generations with year round reproduction (humans)
-smooth curve

Question 5

growth rate

Answer 5

the number of new individuals produced in a given amount of time minus the number of individuals that die

Question 6

intrinsic growth rate (r)

Answer 6

the highest possible per capita growth rate for a population

Question 7

is density independent growth realistic

Answer 7

not always

Question 8

density dependent

Answer 8

factors that affect population size in relation to the population’s density

Question 9

negative density dependence

Answer 9

when the rate of population growth decreases as population density increases
- most commonly limiting resources (food, nesting sites, space)

Question 10

self-thinning curve

Answer 10

a graphical relationship that shows how decreases in population density over time lead to increases in the size of each individual in the population
-often has a slope of -3/2

Question 11

positive density dependence

Answer 11

when the rate of population growth increases as population density increases
- often known as inverse density dependence of Allee effect
-often occur when population densities are very low which makes it hard to find mates
- low densities can also lead to harmful effects such as inbreeding and a higher predation risk

Question 12

carrying capacity (K)

Answer 12

the maximum population size that can be supported by the environment

Question 13

logistic growth model

Answer 13

describes slowing growth of populations at high densities

Question 14

S-shaped curve

Answer 14

the shape of the curve when a population is graphed over time using the logistic growth model

Question 15

inflection point

Answer 15

the point on a sigmoidal growth curve at which the population has its highest growth rate

Question 16

age structure

Answer 16

the proportion of individuals that occurs in different age classes in a population

Question 17

age structure pyramids with broad bases indicate

Answer 17

a growing population

Question 18

age structure pyramids with narrow bases indicate

Answer 18

a declining population

Question 19

life tables

Answer 19

summary of class specific survival and fecundity
-model population growth and dynamics

Question 20

stable age distribution

Answer 20

when the age structure of a population does not change over time
-occurs when survival and fecundity of each age class stays constant over time

Question 21

type 1 survivorship curve

Answer 21

depicts a population that experiences low mortality early in life and high morality later in life
-bears, humans, elephants, and whales

Question 22

type 2 survivorship curve

Answer 22

depicts a population that experiences constant mortality throughout its life span
-squirrels and corals

Question 23

type 3 survivorship curve

Answer 23

depicts a population with high mortality early in life and high survival later in life
-weeds, fish, alligators

Question 24

net reproductive rate (R0)

Answer 24

the total number of female offspring that we expect an average female to produce over the course of her life

Question 25

generation time (T)

Answer 25

the average time between the birth of an individual and the birth of its offspring

Question 26

cohort life table

Answer 26

a life table that follows a group of individuals born at the same time from birth to death of the last individual
-can be difficult to separate the effects of age and the environment

Question 27

static life table

Answer 27

a life table that quantifies the survival and fecundity of all individuals in a population during a single time intervals
-used for highly mobile organisms and species with long life spans