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Environmental Science 4.3-Population Growth

Environmental Science 4.3-Population Growth

Assessment

Presentation

•

Science

•

12th Grade

•

Medium

•
NGSS
MS-LS2-4, MS-LS2-1, MS-LS3-2

+2

Standards-aligned

Created by

Abby Fancsali

Used 5+ times

FREE Resource

25 Slides • 17 Questions

1

Chapter 4.3-Population Growth

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2

Multiple Choice

Which is the simplest level of organization within the environment?

1

cell

2

organism

3

population

4

community

3

Multiple Choice

Which term refers to the study of organisms and their interactions within the environment?
1
biosphere
2
niche
3
ecology
4
habitat

4

Multiple Choice

Which term refers to the place where an organism obtains everything they need to survive?
1
biosphere
2
habitat
3
niche
4
ecology

5

Multiple Choice

Similar organisms that can reproduce with each other are considered to be members of the same _______________.

1

community

2

species

3

biosphere

4

ecosystem

6

Multiple Choice

All the alligators in the same area are an example of a(n) _______________.

1

organism

2

community

3

population

4

group

7

Multiple Choice

Study of populations in relation to environment, including environmental influences on density and distribution, age structure, and population size.

1

population ecology

2

community ecology

3

ecosystem ecology

4

biosphere ecology

8

Multiple Choice

Number of individuals per unit area or volume.

1

denisty

2

dispersion

3

survivorship

4

immigration

9

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Lesson Objectives

  • Describe the factors that influence a population's growth rate

  • Explain Exponential growth and logistic growth

  • Explain how limiting factors and biotic potential affect population growth

10

Open Ended

Bacteria can reproduce once in about four minutes. A whale can reproduce once in a year. Why do you think there is such a large time difference between the two organisms?

11

Population Growth

  • A population increases in size when more individuals enter the population than leave it

    • Entering includes births and immigration

  • A population decreases in size when more individuals leave the population than enter it

    • Leaving includes death and emigration

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12

Birth and Death Rates

  • Natality: the rate at which individuals are born

  • Mortality: The rate at which individuals die

  • Both Values are expressed as a number per 1000 individuals over a given time

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13

Survivorship Curves

  • Individuals of different ages have different probabilities of dying

  • Survivorship Curve: a graph that shows how the likelihood of death varies with age

    • Three types of curve

      • Type I

      • Type II

      • Type III

14

Type I: Survivorship Curve

  • Type I: Most individuals survive young and die old

    • Example: Humans- More 80 year old people die than 10 year old

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Type II: Survivorship Curve

  • Type II: An Individual's age does not affect the probability of their death

    • Example: Most bird species

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16

Type III: Survivorship Curve

  • Type III: Most Individuals die young and adults are more likely to survive

    • Examples: Many plants and amphibians

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17

Multiple Choice

A graphic way of representing the data in a life table.

1

survivorship curve

2

exponential growth curve

3

logistic growth curve

4

lag phase

18

Multiple Choice

If the number of births in a population is the same as the number of deaths in a population, what will happen to the growth of the population?
1
It will increase.
2
It will decrease.
3
It will stay the same.
4
It will fluctuate.

19

Multiple Choice

Which Survivorship Curve describes populations whose mortality is highest at young ages

1

Type I

2

Type II

3

Type III

20

Immigration and Emmigration

  • Individuals in an animal population move around and can leave the population and join another one

    • Immigration: the arrival of individuals from outside the population

    • Emigration: The departure of individuals from a given area

21

Migration

  • Sometimes animals leave an area as part of a seasonal routine

  • Migration: The Seasonal Movement into and out of an area

    • This can lead to large population growth for limited periods of time that eventually return to normal

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22

Calculating Population Growth

  • We can show the population growth with the following equation

    • A positive growth is an increase,

    • A Negative growth is a decrease

23

Calculating Population Growth Example Problem

  • A population's birthrate is 18 per 1000 and its death rate is 10 per 1000. In the same year, 5 individuals joined the population and 7 emigrated. What is the population growth?

24

Calculating Population Growth Example Problem

  • A population's birthrate is 18 per 1000 and its death rate is 10 per 1000. In the same year, 5 individuals joined the population and 7 emigrated. What is the population growth?

25

Fill in the Blank

  • A population's birthrate is 18 per 1000 and its death rate is 10 per 1000. In the same year, 5 individuals joined the population and 7 emigrated. What is the population growth rate per 1000 individuals?

26

Calculating Population Growth Example Problem

  • We can turn the Growth rate into a percentage that can be used to predict changes over time

    • Example: the growth 6/1000 individuals

27

How populations Grow

  • Growth rates are not a static measurement and can change depending on conditions at any given time

  • There are two main modes of population growth

    • Exponential Growth

    • Logistic Growth

28

Exponential Growth

  • Exponential growth: When a population increases by a fixed percentage each year

    • Let's say we have a population of 1,000 individuals that has a growth rate of 10%

      • After the first year, they will increase by 10% (100) and have a total of 1100 in the population

      • After the 2nd year, they will increase by another 10% (110) and have a total of 1210

29

Exponential Growth

  • Exponential Growth occurs when the starting population is small and conditions are ideal

  • Makes a J-shaped graph

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30

Limiting Factors

  • Exponential growth can only last a short time

    • Eventually, some resources run out

  • Limiting Factors: Characteristics of the environment that limit a population growth

  • Carrying Capacity: The Largest population size an environment can support

31

Logistic Growth

  • Logistic growth: A population grows exponentially until it comes close to the carrying capacity, and then slows/stops

    • If Carrying capacity is exceeded, the population will decrease back down to the carrying capacity

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32

Population Growth in Nature

  • In reality, both curves are very simplified models of populations

  • Carrying capacities can fluctuate depending on the circumstances

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33

Multiple Choice

The Largest number of individuals of a population that the environment can support is called the ___________

1

carrying capacity

2

population

3

biome

4

mutualism

34

Multiple Choice

Question image

What type of growth is shown in the diagram?

1

exponential growth

2

logistic growth

3

predator-prey cycle

4

boom-bust curve

35

Multiple Choice

Question image

When a population grows past the ecosystem's carrying capacity, what most likley happens to the population?

1

Continues to grow

2

The population starts to die off to return to carrying capcity

3

The population will go completely extinct due to lack of resources

36

Multiple Choice

Question image

What is the carrying capacity for this sheep population?

1

2.0 million

2

1.0 million

3

1.6 million

4

0.5 million

37

Limiting Factors

  • Limiting Factors can slow population growth

    • can be sorted into two categories

      • Density Dependent

      • Density Independent

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Density-Dependent Factors

  • Density-Dependent Factors: factors whose influence changes depending on how large the population is

    • The more individuals, the more competition for resources

      • Food, water, shelter

    • Larger populations have more chance for disease to spread and predators to attack

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Density-Independent Factors

  • Density-Independent Factors: Factors whose influence is not affected by the size of the population

    • Includes factors like catastrophic events and severe weather

40

Biotic Potential

  • Individuals in a population affect how a population grows just as much as the environment they exist in.

  • Biotic Potential: The maximum ability of individuals to reproduce in ideal conditions

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41

Factors that influence Biotic Potential

  • Gestation Time: How long it takes for offspring to develop before birth

  • Generation time: How long it takes for an individual to reach reproductive age

  • Number of Offspring Produced

42

Categorize

Options (8)

disease

Available Water

Available Food

Predators

Heavy Rain

Low Sunlight

Late Winter

An Earthquake

Organize the following factors into Density-Dependent and Density-Independent

Density Dependent
Density-Independent

Chapter 4.3-Population Growth

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