Population Ecology Chapter 3

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Questions and Answers

What is the primary focus of population ecology?

The study of how members of a population interact with their environment (correct)

The study of the genetic diversity of a population

The study of the evolution of a species over time

The study of how different species interact with each other

What is biogeography?

The study of the interactions between different species

The study of the evolution of a species over time

The study of the population dynamics of a species

The study of the geographic distribution of organisms (correct)

What is dispersal tendency?

The movement of individuals towards centers of high population density

The study of the genetic diversity of a population

The interaction between different species in a population

The movement of individuals away from centers of high population density or from their area of origin (correct)

What is affected by environmental components?

The distribution and abundance of species Signup and view all the answers

What is population ecology concerned with?

The distribution, dispersion, size, density, abundance, dynamics, and structure of a population Signup and view all the answers

What is a species transplant?

An organism that has been intentionally or accidentally relocated from its original distribution Signup and view all the answers

What do ecologists recognize in the distribution of organisms within the biosphere?

Global and regional patterns of distribution Signup and view all the answers

What is the study of the geographic distribution of organisms throughout the landscape?

Biogeography Signup and view all the answers

What is the main characteristic of a Type I curve?

Low death rate early in life Signup and view all the answers

Why do demographers focus on females in a population?

Because they give birth to offspring Signup and view all the answers

What does a reproductive table summarize in a population?

Age-specific reproductive rates Signup and view all the answers

What is the formula for population growth (N) in a population?

N = B - D Signup and view all the answers

What does the symbol ΔN represent in the population growth equation?

The change in population size Signup and view all the answers

What is the per capita birth rate (b) in a population?

The number of offspring produced per unit time by an average member Signup and view all the answers

What type of curve shows a high death rate early in life?

Type III curve Signup and view all the answers

What is the population growth rate, expressed in mathematical notation?

ΔN/Δt = B - D Signup and view all the answers

What is the shape of the growth curve when the population size is plotted over time?

J-shaped Signup and view all the answers

What is the term for the maximum growth rate of a population?

rmax Signup and view all the answers

What is the equation for exponential population growth?

dN/dt = rmax N Signup and view all the answers

What is the term for the number of individuals that the environment can maintain?

Carrying capacity Signup and view all the answers

Why do long periods of exponential growth not occur in the real world?

Because of growth limiting factors Signup and view all the answers

What is a characteristic of a population with a high intrinsic rate of increase?

It grows faster than one with a lower rate Signup and view all the answers

What is an idealized picture of population growth under ideal conditions?

Exponential growth model Signup and view all the answers

What is the factor by which a population multiplies during a constant time interval?

Constant factor Signup and view all the answers

What is the primary purpose of a static life table?

To record the age of individuals at a given time and their age at death Signup and view all the answers

What can be inferred from an age structure diagram with a bottom-wide shape?

The population is increasing Signup and view all the answers

What is the main difference between a static life table and an age distribution?

A static life table records age at death, while an age distribution calculates the proportion of individuals in each age class Signup and view all the answers

What is represented on a survivorship curve?

The number of individuals in a cohort still alive at each age Signup and view all the answers

What can be inferred from an age structure diagram with an inverted pyramid shape?

The population is decreasing Signup and view all the answers

What is the primary advantage of using a static life table for longer-lived organisms?

It is simpler to use for longer-lived organisms that the researcher may not be able to follow across the organism's entire lifetime Signup and view all the answers

What is the purpose of calculating the difference in proportion of individuals in each age class?

To assume differences from mortality Signup and view all the answers

What type of information is not provided by a static life table?

Information on sex ratios Signup and view all the answers

What is the shape of an age structure diagram that indicates a population is experiencing slow growth?

Columnar shape Signup and view all the answers

What is the purpose of creating an age structure diagram?

To analyze the population's growth trends and point to future social conditions Signup and view all the answers

What is a characteristic of populations that are least threatened by extinction?

Extensive geographic range, broad habitat tolerance, and small local populations Signup and view all the answers

What is the main challenge in measuring population density?

It is impractical or impossible to count all individuals in a population Signup and view all the answers

What is the purpose of quadrat sampling technique?

To estimate the population density of a larger area Signup and view all the answers

What type of rarity is characterized by an extensive range, narrow habitat tolerance, and large local populations?

Rarity II Signup and view all the answers

Why do ecologists use sampling techniques to estimate population density?

Because it is impractical or impossible to count all individuals in a population Signup and view all the answers

What is the size of the quadrats typically used in quadrat sampling technique?

1m2 Signup and view all the answers

What is an example of an animal that exhibits Rarity I?

Peregrine Falcon Signup and view all the answers

What is the purpose of statically analyzing data from a few small plots in sampling technique?

To estimate the population density of the larger area Signup and view all the answers

Study Notes

Population Ecology Definitions

Population ecology is the study of how members of a population (same species living in a given area) interact with their environment.
It focuses on factors that influence a population's: distribution, dispersion, size, density, abundance, dynamics, and structure.

Population Distribution

Ecologists use observations and experiments to test explanations for the distribution and abundance of species affected by environmental components.
Biogeography is the study of the geographic distribution of organisms throughout the landscape.
It provides a good starting point for understanding what limits the geographic distribution of species.

Factors that Influence Species Distribution

Dispersal tendency: the movement of individuals away from centers of high population density or from their area of origin that contributes to the global distribution of organisms.
Habitat tolerance: the ability of a species to adapt to different environmental conditions.
Local population size: the number of individuals in a specific area.
Rarity can be divided into three types: Rarity I, II, and III, based on factors such as geographic range, habitat tolerance, and local population size.

Measuring Population Density

Measuring density of populations is a difficult task.
Ecologists use sampling techniques to estimate population density, such as quadrat sampling and life tables.

Sampling Techniques

Quadrat sampling: involves randomly selecting square areas of a specific size within a study site and collecting data of interest within these quadrats.
Static (or time-specific) life table: counts all individuals alive at a given time and records the age of each, and records age at death of individuals.
Age distribution: calculates the difference in proportion of individuals in each age class, assuming differences from mortality.

Age Structure and Population Growth

Age structure diagrams can reveal a population's growth trends and point to future social conditions.
The age structure of a population can help us predict the future growth of populations.
Survivorship curves: a graphic way of representing the data, which plots the number of individuals in a cohort still alive at each age.

Reproductive Rates

Demographers focus on females because only females give birth to offspring.
A reproductive table is an age-specific summary of the reproductive rates in a population.
Birth rate: the number of young born per female.

Population Growth

Population growth (N) = Births (B) minus Deaths (D).
Population growth rate: the change in a population size per time interval.
Per capita birth rate (b): the number of offspring produced per unit time by an average member of the population.
Per capita death rate (m): the number of deaths per unit time by an average member of the population.
Exponential population growth: the size of a population that is growing exponentially increases at a constant rate, resulting in a J-shaped growth curve.

Carrying Capacity (K)

It is the number of individuals in a population that the environment can just maintain (“carry”) with no net increase or decrease.
Growth limiting factors shape the carrying capacity.
Long periods of exponential increases are not common in the real world, as the carrying capacity would eventually be reached.

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Description

Quiz on population ecology definitions, including the study of population interactions with their environment, distribution, dispersion, size, and density.