Population Ecology

Question 1

What is population ecology?

Answer 1

How biotic and abiotic factors influence density, distribution size and age structure of populations

Question 2

Ex of population ecology

Answer 2

Sea turtles

Question 3

What is geographic range?

Answer 3

A measure of the total area covered by a population

Question 4

What is a spatial structure?

Answer 4

The pattern of density and spacing of individuals in a population

Question 5

Small scale variation in the environment creates…

Answer 5

Geographic ranges that are composed of small patches of suitable habitat and quality

Question 6

Geographic distribution example

Answer 6

Geographic range of Fremont’s leather flower is just 3 counties in Missouri
Within the countries, plants are restricted to dry, rocky soils on limestone outcroppings. Plants are further restricted by variation in glade soil

Question 7

We can test whether species are limited by…

Answer 7

Unsuitable environmental conditions

Question 8

Example of distribution

Answer 8

Monkeyflowers
The Lewis’ monkey flower lives at high elevations
The scarlet monkey flower lives lives at low elevations
What happens at different elevations?

Question 9

What is a fundamental niche?

Answer 9

The range of abiotic and biotic conditions under which a species can persist

Question 10

What is a realized niche?

Answer 10

The range of abiotic and biotic conditions under which a species actually persist

Question 11

Which factor is bigger?

Answer 11

Fundamental niche

Question 12

Ecological niche modeling

Answer 12

Process of determining suitable habitats for a species
Predicting potential geographic range of a species is difficult when only a few individuals exist
Researchers can use historic distributions
Understanding realized niche aids in conservation and can limit spread of invasive species

Question 13

Populations often grow larger in…

Answer 13

More suitable habitats

Question 14

Endemic

Answer 14

Species that love in a single often isolated, location

Question 15

Cosmopolitan

Answer 15

Species with very large geographic ranges that can span several continents

Question 16

Example of endemic species

Answer 16

Guadalupe fur seals

Question 17

Example of cosmopolitan species

Answer 17

Harbor seals, pigeons

Question 18

Abundance

Answer 18

Total number of individuals in a population that exist within a defined area

Question 19

Populations with high abundance…

Answer 19

Also have large geographic ranges
This suggests that reducing the range of a population will reduce the size of that population

Question 20

What affects the size of a population and how it changes over time?

Answer 20

Adding individuals to or removing individuals from a population

Question 21

Adding to the population

Answer 21

Birth
Immigration- influx of new individuals from other areas

Question 22

Reducing population

Answer 22

Deaths
Emigration- movement of individuals out of a population

Question 23

Density

Answer 23

Number of individuals per unit area or volume

Question 24

Dispersion

Answer 24

Pattern of spacing among individuals within boundaries of the population

Question 25

Patterns of dispersion

Answer 25

Uniform Random Clumped

Question 26

How do you determine population size and density?

Answer 26

Counting is impractical Tagging is a technique used by scientists

Question 27

Demography

Answer 27

Study of key characteristics of populations and how they change change over time

Question 28

Life table

Answer 28

Summarizes survival and reproductive rates of individuals in specific age-groups in a population

Question 29

Cohort

Answer 29

Group of individuals of the same age, from birth until all of the individuals ate dead Also need to keep track of number of offspring produced by females in each age group

Question 30

Survivorship curve

Answer 30

A graphic way of representing the data in a life table

Question 31

Type I on survivorship curve

Answer 31

Low death rates during early and middle life and an increase in death rates amount older age groups ex. Humans

Question 32

Type II on survivorship curve

Answer 32

A constant death rate over the organisms life span ex. Birds

Question 33

Type III on survivorship curve

Answer 33

Hugh death rates for the young and a lower death rate for survivors ex. Fish, turtles, trees

Question 34

Per capital rate of increase

Answer 34

Change in population size= births + immigrants (entering population) - deaths - emigrants

Question 35

Change in population size formula

Answer 35

R = b - d

Question 36

When would zero population growth occur?

Answer 36

Births = deaths

Question 37

When would population expansion occur?

Answer 37

b > d

Question 38

When would population decline occur?

Answer 38

b < d

Question 39

Exponential growth model

Answer 39

Population increases continuously at an exponential rate Has a j-shaped curve when graphed

Question 40

Exponential growth model equation:

Answer 40

dN/ dt = rN dN/dt rate at which pop. is increasing at each moment in time r intrinsic growth rate/ rate of increase (constant) N current pop. size

Question 41

Assumptions of exponential growth

Answer 41

Resources remain infinite indefinitely

Question 42

Carrying capacity (K)

Answer 42

The max population size that a particular environment can sustain A limit to number of individuals that can occupy a given habitat

Question 43

Things that influence K

Answer 43

Space Time Abundance of limiting resources: energy, shelter, refuge from predators, nutrient availability, water

Question 44

Logistic growth model

Answer 44

Describes slowing growth of populations at high densities Population growth approaches zero as population size nears carrying capacity As population size increase, each individual has access to fewer resources resulting in a lower rate if population growth

Question 45

Logistic growth model equation

Answer 45

dN/dt = rN (K-N)/K K-N number of additional individuals the environment (K-N)/K fraction of K that is still available for population growth

Question 46

When N is small compared to K (K-N)/K is close to 1

Answer 46

Exponential growth

Question 47

When N is large compared to K (K-N)/K is close to 0

Answer 47

Growth rate is small

Question 48

When N=K

Answer 48

Population stops growing

Question 49

S-shaped curve

Answer 49

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

Question 50

Inflection point

Answer 50

The point on a growth curve at which the population had the highest growth rate

Question 51

Logistics growth model can be used to…

Answer 51

Predict how rapidly a pop. may increase after it has been reduced to a small size Estimating sustainable harvest rate for wildlife populations Estimate critical size below which populations may become extinct