1. Population Ecology 4
CHAPTER
Big Question: How do changes in population size relate to environmental conditions?
Placeholder opening page, but maybe we can duplicate the look of the SE chapter opener page by using the same fonts and colors (and maybe that Ch 14 icon?)

2. Finding Gold in a Costa Rican Cloud Forest
Golden toads lived in Costa Rica’s Monteverde cloud forest.
Golden toads were first described in They were extinct by 1989.
Talk About It Why is the extinction of the golden toad a global concern?

3. Lesson 4.1 Studying Ecology
Ernst Haeckel defined ecology in 1866 as “the body of knowledge concerning the economy of nature—the total relations of the animal to both its inorganic and organic environment.”

4. Lesson 4.1 Studying Ecology Objectives
Describe the different levels of organization studied by ecologists.
Explain the difference between biotic an abiotic factors.
Discuss how an organism’s habitat relates to its survival.

5. Ecology
Ecologists study life at many levels, from individual organisms to the entire biosphere.
The study of how organisms interact with each other and with their environments.

6. Levels of Ecological Organization
Lesson 4.1 Studying Ecology
Levels of Ecological Organization
The study of how organisms interact with each other and with their environments
Scientists study ecology at various levels of organization.

7. Biotic and Abiotic Factors
Lesson 4.1 Studying Ecology
Biotic and Abiotic Factors
Biotic factors: Parts of an ecosystem that are living or used to be living
Abiotic factors: Parts of an ecosystem that have never been living
Did You Know? Decaying organisms are biotic factors as long as their structure remains cellular.

8. Habitat The specific environment in which an organism lives
Lesson 4.1 Studying Ecology
Habitat
The specific environment in which an organism lives
Habitats provide an organism with resources—anything an organism needs to survive and reproduce, including food, shelter, and mates.

9. Lesson 4.1 Studying Ecology Assessments
Apply Concepts: Would all the different kinds of organisms in a pond be considered a population or a community? Explain.
Explain: In your own words, explain how an organism can be dead, yet still considered a biotic factor.
Apply Concepts: Why do different organisms live in different habitats?
Big Question: For each of the levels of ecological organization, state whether it contains only biotic factors, only abiotic factors, or both biotic and abiotic factors.

10. Lesson 4.2 Describing Populations
From 1900 to 2000, the white-tailed deer population of New York state grew from about 20,000 to more than 1 million. Densities of more than 100 deer per sq mi occur in some metropolitan areas.

11. Lesson 4.2 Describing Populations Objectives
Explain the usefulness of tracking population size.
Define population density.
Describe the three ways populations can be distributed.
Explain what age structure diagrams tell you about a population.

12. Lesson 4.2 Describing Populations
Population Size
The number of individuals in a population at a given time
Sudden and dramatic decreases in population size can indicate an unhealthy population headed toward extinction.
Ecologists often use sampling techniques to estimate population size.
Did You Know? The passenger pigeon was once North America’s most abundant bird. Hunting drove them to extinction in less than 100 years.
Counting Laysan Albatross Nests

13. Population Density Measure of how crowded a population is
Lesson 4.2 Describing Populations
Population Density
Measure of how crowded a population is
Larger organisms generally have lower population densities.
Low population density: More space, resources; finding mates can be difficult
High population density: Finding mates is easier; tends to be more competition; more infectious disease; more vulnerability to predators
Northern pintail ducks

14. Population Distribution
Lesson 4.2 Describing Populations
Population Distribution
How organisms are arranged within an area:
Random distribution: Organisms arranged in no particular pattern
Uniform distribution: Organisms evenly spaced
Clumped distribution: Organisms grouped near resources; most common distribution in nature

15. Name that distribution type!
Clumped!

16. Name that distribution type!
Random !

17. Name that distribution type!
Uniform!

18. Lesson 4.2 Describing Populations
Age Structure
Relative number of organisms of each age group within population
Can be used to predict future population growth of a population

19. Sex Ratios Proportion of males to females
Lesson 4.2 Describing Populations
Sex Ratios
Proportion of males to females
Age structure diagrams give information about sex ratios.
For a monogamous species, the ideal sex ratio is 50:50.

20. Lesson 4.2 Describing Populations Assessments
Relate Cause and Effect: How is a population’s size related to its well-being?
Calculate: Which population of flamingos is more dense: 15 flamingos in a 5-square-meter area, or 40 flamingos in a 10-square-meter area?
Apply Concepts: Describe the three patterns of population distribution. Which of these is the most common distribution in nature?
Infer: Which of the populations shown in Figure 6 do you think is most likely to get bigger in size? Explain your reasoning.

21. Lesson 4.3 Population Growth
From 1800 to today, the human population has grown from about 1 billion to more than 6.8 billion—an exponential rate of increase.

22. Lesson 4.3 Population Growth 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.

23. Lesson 4.3 Population Growth
Birth and Death Rates
A population’s relative birth and death rates (mortality and natality) affect how it grows.
Survivorship curves show how the likelihood of death varies with age.

25. Birth or death rate per 1,000 population
Birth and death rates and age structure affect population growth
The demographic transition
Is the shift from high birth rates and death rates to low birth rates and death rates 50 40 30 20 10
1900
1925
1950
1975
2000
2025
2050
Year
Birth rate
Death rate
Birth or death rate per 1,000 population
Figure 36.10A

26. Immigration and Emigration
Lesson 4.3 Population Growth
Immigration and Emigration
In addition to births and deaths, population growth is affected by immigration and emigration—individuals moving into and out of a population.
Migration, seasonal movement into and out of an area, can temporarily affect population size.

27. Calculating Population Growth
Lesson 4.3 Population Growth
Calculating Population Growth
Determined by the following equation:
(birthrate + immigration rate) – (death rate + emigration rate)
Growing populations have a positive growth rate; shrinking populations have a negative growth rate.
Usually expressed in terms of individuals per 1000

28. Did You Know? Immigration contributes more than 1 million people to the U.S. population per year.

29. Lesson 4.3 Population Growth
Exponential Growth
Population increases by a fixed percentage every year.
Normally occurs only when small populations are introduced to an area with ideal environmental conditions
Rarely lasts long

30. Logistic Growth and Limiting Factors
Lesson 4.3 Population Growth
Logistic Growth and Limiting Factors
Growth almost always slows and stops due to limiting factors.
Limiting factors: Environmental characteristics slow population growth and determine carrying capacity.

31. What can Impact the Carrying Capacity of a Population
Density Dependent Limiting Factors
Density-dependent: Influence changes with population density.
Density Independent Limiting Factors
Density-independent: Influence does not change with population density.

32. Identify if the following are DENSITY-DEPENDENT OR DENSITY-INDEPENDENT LIMITING FACTORS:
Humans altering ecosystem
Not enough food
Predators
Parasites
Not enough space
Construction
Diseases
Build-up of wastes

33. Lesson 4.3 Population Growth
Biotic Potential
An organism’s maximum ability to produce offspring in ideal conditions
Many factors influence biotic potential, including gestation time and generation time.
Organisms with high biotic potential can recover more quickly from population declines than organisms with low biotic potential.

34. Lesson 4.3 Population Growth Assessments
Calculate: A population has a birthrate of 10/1000, a death rate of 9/1000, an immigration rate of 3/1000, and an emigration rate of 7/ What is the population’s growth rate? Is the population getting larger or smaller?
Compare and Contrast: What is the difference between exponential growth and logistic growth? Which is more common over long terms in nature?
Apply Concepts: In your own words, define limiting factor and biotic potential.