Chapter 10 - Population Growth and Regulation

Question 1

Provides a summary of how survival and reproductive rates vary with the organism’s age.

Answer 1

Life Table

Question 2

Components of a Life Table

Answer 2

Nx = number of individuals alive at a given age x (or age range) within a span of time.

Sx = survival rate. Chance that an individual will survive to the next age (x + 1).

lx = survivorship. Proportion of individuals that survive from birth (age 0) to age x.

Fx = fecundity. Number of offspring produced by a female at age x.

Question 3

Records the fate of a group that was born at the same time and is observed from birth to death usually for observing shorter life spans

Answer 3

Cohort Life table

Question 4

Analyzes the fate of a group from estimated ages or an already existing record of a particular period or time usually for observing loner life spans

Answer 4

Static Life Table

Question 5

Uses lx (Survivorship) to plot the number of individuals in a hypothetical cohort (transformed to 1000 individuals) that will survive to reach different ages. Varies among species and may also vary in interspecies populations or among cohorts .

Answer 5

Survivorship curve

Question 6

Three types of survivorship curves

Answer 6

Type I - Death rate increases as they reach old age

Type II - Near-constant trend, almost linear

Type III - High death rate among young with few survivors

Question 7

The category or specified age range, where everyone in a population may belong to

Answer 7

Age class

Question 8

Summary of proportion of the population that belong to a set of age ranges

Answer 8

Age structure

Question 9

How to calculate predicted no. of individuals surviving to the next period (ex. breeding cycle seasons)

Answer 9

Predicted no. of individuals surviving to the next period = nx * Sx

Where: nx = no. of individuals in an age class
Sx = survival rate of the age class.

Question 10

How to calculate the number of newborns the survivors will produce in the next period. (applies to fertile age range with recorded offspring).

Answer 10

= (average # of offspring of an age range * # of individuals of that age range)+…

Question 11

The ratio of the population in one time point and the previous. “How fast did the population increase/decrease within that time span.

Answer 11

Population Growth Rate

Population growth rate (λ) = Nt+1 / Nt

Question 12

Populations grow at fixed rates when?

Answer 12

Age-specific birth and death rates are constant over time

Question 13

The point when the age structure of a population does not increase nor decrease from one time point to another.

Answer 13

Stable age distribution

Question 14

T/F Populations can grow indefinitely exponentially when conditions are favorable.

Answer 14

Populations can grow exponentially when conditions are favorable. But not indefinitely.

Question 15

Two related patterns of population growth, helping in rapid increase of population size:

Answer 15

Geometric growth
Exponential growth

Question 16

Population grow geometrically when?

This applies to organisms that have a synchronous reproductive time

Answer 16

Reproduction occurs at regular time intervals

Question 17

Refers to the regular intervals of reproduction

Answer 17

Discrete time period

Question 18

This growth is characterized when population changes in size by a constant proportion from one discrete time period to another

Answer 18

Geometric Growth

Question 19

Population with continuous reproduction changes in size by a constant proportion in each instant in time, J-shaped curve

Answer 19

Exponential Growth

Question 20

Formula to find the population size at t generations for geometric growth

Answer 20

Nt= λ^t / N0

Where Nt is the population size after t generations
N0 is the Initial Population size
And λ is the geometric growth/ratio

Question 21

How to solve for population size at each instant of time for Exponential growth

Answer 21

dN/dT = rN
N(t) = N(0)e^(rt)

where:
N(t) is the population at time t
N(0) is the starting population
dN/dT is the rate of change in population size
r = constant rate of increase
N = Current population size
e = Euler’s Number = 2.718

Question 22

Number of years a population will take to double in size

Answer 22

Doubling time (td) = ln(2)/r

where R is the exponential growth rate

Question 23

Mean number of offspring produced by an individual during its lifetime.

Answer 23

Net Reproductive Rate (R0)

= summation of (lx * Fx) from x_first to x_last

where
x = age
xfirst = age of first reproduction
xlast = age of last reproduction
lx = survivorship
Fx = fecundity

Question 24

Cause birth rates, death rates, or dispersal rates to change as the population density changes

Answer 24

Density Dependent Factors

Question 25

Occurs when one or more density-dependent factors cause population size to increase when numbers are low and decrease when numbers are high

Answer 25

Population Regulation

Question 26

Pattern in which abundance increases rapidly at first and then stabilizes at the carrying capacity; s-shaped curve

Answer 26

Logistic Growth

Question 27

The total area of productive ecosystems required to support a population

Answer 27

Ecological footprint