Population Ecology

Question 1

Things you should know (3)

Answer 1

1. How density, dispersion and demographics can
   describe a population.
2. The differences between exponential and
   logistical models of population growth.
3. How density-dependent and density-idenpendent
   factors can control population growth.

Question 1

Levels of Complexity (5)

Answer 1

Individual
Population
Community
Ecosystem
Biosphere

Question 2

Group of individuals of same species in same area at same time.

Often described by their boundaries and size

Answer 2

Population

Question 3

Rely on same resources
Interact
Interbreed

Answer 3

Population

Question 4

Study the factors that cause population to increase and decrease (3)

Answer 4

Input Immigration & Births
>
Population Size
> Output Emigration & Deaths

Question 5

Why population Ecology? (2)

Answer 5

Scientific goal: understanding the factors that influences the size of populations

Practical goal: management of populations

Question 6

Under scientific goal of population ecology (2)

Answer 6

General principles
Specific cases

Question 7

Under practical goal of population ecology (3)

Answer 7

Increase population size (endangered species)
Decrease population size (pests)
Maintain population size (fisheries management)

Question 8

Factors that affect Population size (3)

Answer 8

Abiotic factors
Biotic factors (behavior/interactions): other livign organisms
Intrinsic factors (adaptations)

Question 9

Abiotic factors

Answer 9

Sunlight and Temperature
Precipitation and water
Soil and Nutrients

Question 10

Biotic factors

Answer 10

Prey (food)
Competitiors
Predators, Parasites, Disease

Question 11

Characterize Population: Range
Geographical Limitations

Answer 11

Abiotic and biotic factors

Habitat

Question 12

Characterize Population: Density

Answer 12

Add: immigration, births.
Remove: emigration, deaths.

Sampling techniques more common: mark and recapture

Rare: count all individuals. Difficult to count a moving target.

Question 13

Number of individuals per unit area of volume

Answer 13

Density

Question 14

The number of individuals that live in a defined area.

Is a measurement of the number of individuals living in a defined space.

Answer 14

Population Density

Question 15

Population density formula

Answer 15

of individuals / area (units^2) = population density

Question 16

Regulation of Population Size

Answer 16

Density Dependent:
Competition (food, mates, nesting sites)
Predators, parasites, pathogens.

Density Independent:
abiotic factors

Question 17

Characterize Population: Dispersion (3)

Answer 17

Clumped Pattern (most common)

Uniform (rare)

Random

Question 18

Spacing among individuals within the boundaries of the popultion

Provides insight into the environmental associations and social interactions of individuals in population.

Answer 18

Dispersion

Question 19

Individuals are aggregated in clumps. Why? (3)

Answer 19

Microenvironment satisfies organism’s requirements

May be associated with mating behavior

May increase effectiveness of predation (wolves)

Question 20

May result from direct interactions between individuals in the population (ex. territoriality)

Answer 20

Uniform

Question 21

The position of each individual is independent of other individuals. (ex. dandelion seeds dispersal)

Answer 21

Random

Question 22

Population growth patterns (2)

Answer 22

Changes in a population’s size are determined by immigration, births, emigration, and deaths.

Population growth is based on available resources.

Question 23

Factors that affect the size of a population (4)

Answer 23

Immigration
Births
Emigration
Deaths

Question 24

Is a rapid population increase due to an abundance of resources.

Answer 24

Exponential growth

Question 25

Population growth models (2)

Answer 25

Exponential growth model Logistic growth model

Question 26

Growth rate formula

Answer 26

Growth rate = number of offspring - deaths

Question 27

Under ideal conditions (with unilimited resources) each species has a particular: the max for that species

Answer 27

intrinsic growth rate

Question 28

Model calculates the maximum rate and displays it as a ___ (because there are no limits)

Answer 28

J-shaped curve

Question 29

Includes environmental limits on the population growth

Answer 29

Logistic growth model

Question 30

As the population reaches the ___, the growth slows and then stops.

Answer 30

carrying capacity

Question 31

The logistic growth model produces a ___

Answer 31

S-shaped curve

Question 32

Some populations cycle above and below the carrying capacity - this is ___ followed by ___

Answer 32

overshoot, die-off

Question 33

___ (K): Number of individuals in a population that the environmental resources can support

Answer 33

Carrying capacity

Question 34

When population reaches carrying capacity, growth rate is zero (N=K, r= 0)

Answer 34

Zero population growth (ZPG): when r = 0

Question 35

Exponential (___) Logistic (___)

Answer 35

Un-restricted Restricted

Question 36

is due to a population facing limited resources

Answer 36

Logistic growth

Question 37

A ___ is a dramatic decline in the size of a population over a short period of time.

Answer 37

Population crash

Question 38

____ limit population growth

Answer 38

Ecological factors

Question 39

A ___ is something that keeps the size of a population down.

Answer 39

Limiting factor

Question 40

___ limiting factors are affected by the number of individuals in given area

Answer 40

Density-dependent (predation competition parasitism and disease)

Question 41

____ limiting factors limit a population's growth regardless of the density.

Answer 41

Density-independent (Unusual weather Natural disasters Human activity)

Question 42

Reproductive strategies (2)

Answer 42

K-selected R-Selected

Question 43

Late reproduction Few offspring Invests a lot in raising offspring

Answer 43

K-selected (ex. Primates, walnut trees)

Question 44

Early reproduction Many offspring Little parental care

Answer 44

r-selected (ex. Insects, many plants)

Question 45

Study of the vital statistics of populations and how they change over time.

Answer 45

Demography

Question 46

Age specific summaries of the survival pattern of a population.

Answer 46

Life tables (ex. Belding ground squirrels - Spermophilus beldingi)

Question 47

Graphic representation of life table

Answer 47

Survivorship curve

Question 48

In survivorship curves, relatively straight lines of the plots indicate ___ rates of death

Answer 48

relatively constant

Question 49

3 types of survivorship curves generalized strategies

Answer 49

Type 1. High death rate in post-reproductive years (large mammals, humans) Type 2. Constant mortality rate throughout life span (lizards, invertebrates, annual plants) Type 3. Very high early mortality but the few survivors then live long/stay reproductive (long-lived plants, oysters)

Question 50

Relative number of individuals of each age

Answer 50

Age structure

Question 51

Factors affecting population growth rate (3)

Answer 51

Sex ratio Generation time Age structure

Question 52

Characteristics of K-selected species

Answer 52

Large Later maturing Few offspring Substantial parental care