Chapter 9: Population Growth

Question 1

Populations in which immigration or emigration occurs

Answer 1

open populations

Question 2

Those in which movement into and out of the population does not occur (or is not a significant influence on population growth)

Answer 2

closed populations

Question 3

Instantaneous rate of population growth, expressed as proportional increase per unit of time

Answer 3

exponential population growth (r)

Question 4

Tabulation of mortality and survivorship of a population

Answer 4

life table

Question 5

Life tables based on a cross section of a population at a given time

Answer 5

Static, time-specific, or vertical life tables

Question 6

Life tables based on a cohort followed throughout life

Answer 6

Dynamic, cohort, or horizontal life tables

Question 7

A group of individuals of the same age

Answer 7

cohort

Question 8

In the analysis of life tables, it is the probability at birth of surviving to any given age (x)

Answer 8

survivorship

Question 9

A graph that plots mortality rates in terms of qx as a function of age

Answer 9

mortality curve

Question 10

A graph describing the survival (lx) of a cohort of individuals in a population from birth to the maximum age reached by any one member of the cohort

Answer 10

survivorship curve

Question 11

3 major types of survivorship curves

Answer 11

Type I: in which individuals tend to live out their lifespan

Type II: in which mortality and thus survivorship are constant through all ages

Type III: in which the survival rate of the young is low

Question 12

Random variations in birth and death rates that occur in a population from year to year

Answer 12

demographic stochasticity

Question 13

Random variations in the environment that directly affect birth and death rates

Answer 13

environmental stochasticity

Question 14

Let’s talk about population decline and extinction

Answer 14

A variety of factors can result in a population declining to extinction, including environmental stochasticity, the introduction of new species, and habitat destruction.

The primary cause of species extinctions is habitat destruction resulting from the expansion of human populations and activities.

Declining populations are a result of both a reduction in the area of habitat available to support populations and a decline in the growth rate of populations that inhabit remaining areas of habitat.

The latter is a result of the degradation of remaining habitats because of human activities.