Population density

Question 1

What are populations?

Answer 1

Groups of the same species in the same area

Population Characteristics

Question 2

What are the characteristics of populations?

Answer 2

Density, distribution, and growth rate

Population Characteristics

Question 3

What is population density?

Answer 3

The number of organisms per unit area

Population Characteristics

Question 4

What is the density of Black Bears?

Answer 4

One bear per several hundred square kilometers

Density

Question 5

What is the density of American Bison in Northern Yellowstone in 2000?

Answer 5

Four bison/lan

Density

Question 6

What is the density of White-tailed Deer in some areas of the northeastern United States?

Answer 6

10 deer/kin*

Density

Question 7

What are populations?

Answer 7

Groups of the same species in the same area

Population Characteristics

Question 8

What are the characteristics of populations?

Answer 8

Density, distribution, and growth rate

Population Characteristics

Question 9

What is population density?

Answer 9

The number of organisms per unit area

Population Characteristics

Question 10

What is the density of Black Bears?

Answer 10

One bear per several hundred square kilometers

Density

Question 11

What is the density of American Bison in Northern Yellowstone in 2000?

Answer 11

Four bison/lan

Density

Question 12

What is the density of White-tailed Deer in some areas of the northeastern United States?

Answer 12

10 deer/kin*

Density

Question 13

What is clumping in population dispersion?

Answer 13

Most common. Safety in numbers, social interaction, mating and caring for young, resources are clumped

Example: A herd of elephants clustering around a watering hole.

Question 14

What is uniform distribution in population dispersion?

Answer 14

Not as common. Used because of scarcity of resources

Example: Trees in a forest spaced evenly apart to maximize access to sunlight and nutrients.

Question 15

What is random distribution in population dispersion?

Answer 15

Quite rare. Can be hard to determine between truly random or largely ‘clumpy’

Example: The distribution of wildflowers in a meadow.

Question 16

What is population density?

Answer 16

Population density is the number of individuals of a species per unit area.

Population density = Number of individuals / Unit area

Question 17

What are the differences between population density and distribution?

Answer 17

Population density refers to the number of individuals per unit area, while distribution refers to the spatial arrangement of individuals in a population.

Population density = Number of individuals / Unit area
Distribution = Spatial arrangement of individuals

Question 18

A population of 820 insects lives in a 1.2-acre area. They gather nectar from a population of 560 flowering plants. The plants live in a 0.2-acre area. Which population has greater density, the insects or the plants? Why?

Answer 18

The insects have greater density because there are more individuals (820) per unit area (1.2 acres) compared to the plants (560) per unit area (0.2 acres).

Population density = Number of individuals / Unit area

Question 19

What can you infer (or guess) about a species that has a random pattern of distribution over space? A uniform pattern?

Answer 19

A species with a random pattern of distribution likely has resources evenly distributed, while a species with a uniform pattern may have resources clumped together.

Random pattern: Evenly distributed resources
Uniform pattern: Clumped resources

Question 20

Be able to identify the three distribution patterns from an image or description.

Answer 20

The three distribution patterns are random, uniform, and clumped.

Distribution patterns: Random, Uniform, Clumped

Question 21

What are limiting factors?

Answer 21

Any abiotic (non-living) or biotic (living) factor that restricts the numbers, reproduction, or redistribution of organisms is called a limiting factor.

Example: Sunlight, climate, temperature, water, nutrients, fire, soil chemistry, and space

Question 22

What are examples of abiotic limiting factors?

Answer 22

Abiotic limiting factors include: sunlight, climate, temperature, water, nutrients, fire, soil chemistry, and space.

Example: Sunlight, climate, temperature, water, nutrients, fire, soil chemistry, and space

Question 23

What are examples of biotic limiting factors?

Answer 23

Biotic limiting factors include other plant and animal species.

Example: Other plant and animal species

Question 24

How are limiting factors classified in terms of populations?

Answer 24

Limiting factors are either density-independent or density-dependent.

Not applicable

Question 25

What is a density-independent factor?

Answer 25

Any factor in the environment that does not depend on the number of members in a population. ## Footnote Not applicable

Question 26

What is reproduction, or redistribution of organisms called?

Answer 26

Limiting factor ## Footnote Example sentence: Auto tat estes me

Question 27

What are some abiotic limiting factors?

Answer 27

Sunlight, climate, temperature, water, nutrients, fire, soil chemistry, and space ## Footnote None

Question 28

What are some biotic limiting factors?

Answer 28

Other plant and animal species ## Footnote None

Question 29

What are density-independent limiting factors?

Answer 29

Any factor in the environment that does not depend on the number of members in a population per unit area ## Footnote None

Question 30

What are some examples of density-independent limiting factors?

Answer 30

Weather events, fire, human alterations of the landscape, air, land, and water pollution ## Footnote None

Question 31

What are density-independent limiting factors?

Answer 31

Any factor in the environment that does not depend on the number of members in a population per unit area is a density-independent factor. ## Footnote Usually abiotic, and include: - Weather events - Fire - Human alterations of the landscape - Air, land, and water pollution

Question 32

What are some examples of density-independent limiting factors?

Answer 32

Weather events Fire Human alterations of the landscape Air, land, and water pollution ## Footnote These are all examples of density-independent limiting factors.

Question 33

What are density-dependent limiting factors?

Answer 33

Any factor in the environment that depends on the number of members in a population per unit area is a density-dependent factor. ## Footnote Often biotic, and include: - Predation - Disease - Competition - Parasites

Question 34

What are some examples of density-dependent limiting factors?

Answer 34

Predation Disease Competition Parasites ## Footnote These are all examples of density-dependent limiting factors.

Question 35

What is the exponential growth model?

Answer 35

Occurs when growth rate is proportional to population size ## Footnote Example: The population of bacteria doubles every hour.

Question 36

When do all populations grow exponentially?

Answer 36

Until they encounter a limiting factor ## Footnote Additional information: This limiting factor can be food availability, space, or predation.

Question 37

What is the lag phase in exponential population growth?

Answer 37

The phase where population growth is slow or stagnant before exponential growth begins ## Footnote Example: In a new habitat, a population of insects may have a lag phase before a sudden increase in numbers.

Question 38

Exponential growth

Answer 38

growth rate is proportional to population size

Question 39

All populations

Answer 39

grow exponentially until they encounter a limiting factor

Question 40

Logistic growth model

Answer 40

Occurs when a population's growth slows or stops following exponential growth ## Footnote A population stops increasing when the number of births < number of deaths, or when emigration > immigration.

Question 41

Carrying capacity

Answer 41

Population limit where growth rate stabilizes ## Footnote Stable population size

Question 42

Exponential growth

Answer 42

growth rate is proportional to population size

Question 43

All populations

Answer 43

grow exponentially until they encounter a limiting factor

Question 44

Logistic growth model

Answer 44

Occurs when a population's growth slows or stops following exponential growth ## Footnote A population stops increasing when the number of births < number of deaths, or when emigration > immigration.

Question 45

Carrying capacity

Answer 45

Population limit where growth rate stabilizes ## Footnote Stable population size

Question 46

What are the four things that impact population size?

Answer 46

Food, water, predation, and disease ## Footnote These are all examples of density limiting factors.

Question 47

Anything that restricts the number of organisms in an environment is called a factor.

Answer 47

Factor

Question 48

What term describes the maximum number of individuals in a species that an environment can support?

Answer 48

Carrying capacity

Question 49

Usually abiotic, any factor that does not depend on the number of members of a population is known as a density limiting factor.

Answer 49

Density limiting factor

Question 50

How is a logistical growth model different from an exponential growth model?

Answer 50

A logistical growth model includes a carrying capacity, while an exponential growth model does not. ## Footnote A logistical growth model shows a population growth that slows down as it reaches its carrying capacity, unlike an exponential growth model which shows unlimited growth.