Unit 4: Populations – Exponential Growth & Finite Resources

Description:

This unit is devoted to the study of populations in nature, their growth over time, and the limits

to their growth. We will also take an in-depth look at the human population of our world, how it

has grown and changed over time to reach 7 billion people today, and what might be ahead of

us in the future. We will focus on achieving long-term sustainability and improving the quality of

life for all of mankind.

Unit Socratic Seminar Question: How and why has the human population changed over time, and is there a carrying capacity for

the planet?

Packet Contents:

Assignments: Due:

1. Chapter 6 Vocabulary 11/3

2. Reading Questions 6A 11/6

3. Reading Questions 6B + Chapter 7 Vocabulary 11/12

4. Reading Questions 7A 11/14

5. Reading Questions 7B 11/17

Schedule:

Date Graded/Due Read Tonight RQ

M 11/3 Chapter 6 Vocab p.149-154

T 11/2 p.154-158

W 11/5 p.159-160

Th 11/6 *DUE: RQ 6A p.161-167 6A

F 11/7 p.168-171

S/S

M 11/10 No School p.179-181 6B

T 11/11 No School p.181-188

W 11/12 Due RQ 6B + Chapter 7 Vocab

Th 11/13 p.188-190 7A

7B

F 11/14 *DUE: RQ 7a p.191-197

S/S

M 11/17 *DUE: RQ 7b

T 11/18 *Socratic Seminar

W 11/19 *Socratic Seminar Study! Study!

Th 11/20 *Unit 4 Test (30 MCQ, 1 FRQ) QuizStars Due by 8:00am

F 11/21

Unit Socratic Seminar question: How and why has the human population changed over time,

and is there a carrying capacity for the planet?

Videos

Mother: Caring for 7 Billion (http://www.youtube.com/watch?v=hdEspxlq3bo) – 1 hour documentary with great footage examining the most pressing population issues of our day from a global perspective. Great examples to draw on in AP test or as sparks of interest. Take notes in the space below:

SUMMARIZE MAIN IDEAS AS YOU WATCH:

Your own questions or opinions/reactions:

Conclusions & Connections to our Unit Focus Q:

.

Chapter 6 Vocabulary List

Population density - Limiting resource -

Population distribution - Carrying capacity (k) -

Age structure - Overshoot -

Density-dependent factors - Density-independent factors -

Growth rate - Intrinsic growth rate (r) -

Exponential growth model - Logistic growth model -

k-selected species - r-selected species -

Corridors - Metapopulations -

Competitive exclusion principle - Resource partitioning -

Parasitoids - True predators -

Keystone species - Predator-mediated competition -

Ecosystem engineers - Ecological succession -

Primary succession - Secondary succession -

Pioneer species - Theory of island biogeography -

Reading Questions 6A

New England Forests Come Full Circle

Nature exists at several levels of complexity.

Population ecologists study the factors that regulate population abundance and distribution.

Growth models help ecologists understand population changes.

1. Fill in 5 key events in the re-establishment of the New England forest in the Opening Story:

1. Farmers begin leaving

2. 3. 4. 5. 6. 7. Broadleaf forest re-established

2. Distinguish between each level of analysis:

What does this level consist of? What do scientists study at this level?

Individual

Population All the individuals of a single species living in a given area at one time

Community

Ecosystem

Flows of energy and matter or a large scale (ex: the cycling of C/N/P/H2O in a lake)

Biosphere

3. Which level of analysis would be most appropriate for a scientist to use in each scenario?

i. Monitoring the Grey Wolves of Yosemite

ii. Investigating the connections among organisms in a soil sample

iii. Determining whether or not natural selection favors light or dark coloration in

mice

iv. Evaluating the status of the Florida Everglades

4. How does the Opening Story demonstrate the importance of community-level analysis and

interactions between species?

5. When considering a population as a system, what 2 processes are inputs that increase

population size and what 2 processes are outputs that decrease population size?

Input 1 (+): Output 1 (-):

Input 2 (+): Output 2 (-):

6. Key Idea: Five major characteristics help us understand how populations change over time:

Why is this factor important?

How could this factor apply to the New England forest in the Opening Story?

Population Size

Population Density

Population Distribution

Population Sex Ratio

Ecologists may study the percentage of female Microrhopala vittata beetles

Population Age Structure

Determines future growth potential (via individuals of reproductive age)

7. Key Idea: Density-dependent factors & density-independent factors can affect population

sizes and growth rates:

a. True/false: Wildfires occurring in the Southern California chaparral (shrubland biome)

influence populations of local species in a density-dependent way.

b. What variable served as the limiting resource in Gause’s paramecium experiment?

__________

c. Explain how the carrying capacity (k) of an environment is determined:

d. What are common limiting resources for terrestrial plants?

e. What are common limiting resources for animal populations?

f. True or false: Density-independent factors deal with limiting resources

8. Predict what would happen to the population sizes of P. aurelia and P. caudatum if Gause had

continued his experiment by alternating between high-food and low-food conditions each day:

9. The Exponential Growth Model

a. What does the intrinsic growth rate (r) for a species measure?

b. Chart the growth of the following population of mice at a growth rate of 10% per year:

Year: 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Mice: 100

10. The Logistic Growth Model

a. Why is the exponential growth model usually insufficient to describe real populations?

b. How does the population growth rate CHANGE as it approaches the carrying capacity of

its environment, and why?

c. What factors prevent the continued growth of populations beyond the carrying

capacity?

11. Variations on Logistic Growth

a. Why is population overshoot always followed by a die-off?

b. True/false: during population overshoot, the environment’s carrying capacity increases.

12. Reproductive Strategies and Survivorship Curves

a. Characteristics of k-selected and r-selected species:

Characteristics Reproduction Speed

Likely to overshoot?

Example Survivorship Curve Type

k-selected species

Type I

r-selected species

Small, short lives, many offspring

b. Which type of species can evolve faster? Explain why.

c. True/false: Most organisms show strict k-selected or r-selected reproduction strategies

d. Which type of species is at greater risk for extinction? Explain why.

13. What is a metapopulation, and why is it important to study them?

Reading Questions 6B

Remember: “Interactions among populations create the Community Dynamics of an ecosystem”

Community ecologists study species interactions.

The composition of a community changes over time.

The species richness of a community is influenced by many factors.

Working Toward Sustainability: Bringing Back the Black-Footed Ferret

1. Competition (-/-)

a. Why did Gause’s experiment growing 2 strains of paramecium in the same environment

produce a different outcome from when they he grew them separately?

b. Why can’t two species simultaneously share the same realized niche?

c. Why is resource partitioning advantageous for species that would otherwise be

competing?

d. Identify each of the following as an example of (1: the competitive exclusion principle),

(2: temporal resource partitioning), (3: spatial resource partitioning) or (4:

morphological resource partitioning):

i. Several species of Warbler Birds hunt insects in the same types of trees, but

each feeds in a different part of the tree

ii. When wolves were absent from Yosemite, deer grazed many plant species so

heavily that other herbivore species were unable to establish themselves

iii. Many different species of bats use a single watering hole, but each at different

times

iv. Different species of butterfly have tongues of varying lengths, each specialized

to the shape of the flowers produced by the plants it feeds on

v. Invasive species that out-compete native species for key resources often drive

the native species to extinction

e. How can species coexistence produce a stable point of equilibrium?

2. Predation (+/-)

a. List 2 distinguishing characteristics of each type of predation:

Characteristic 1 Characteristic 2

True predators

Herbivores

Parasites

Parasitoids

b. How are herbivorous prey able to defend themselves?

3. Mutualism (+/+)

a. Under what conditions would natural selection favor mutualism between two species?

b. True/false: In a mutualistic relationship, neither species evolves traits suited to helping

the other

c. Which of the following are mutualistic: (Lichens) (Viruses) (Coral) (Acacia trees) (African

lions)

4. Commensalism (+/0)

a. True/false: In commensalism, both species benefit

b. True/false: Most vines (epiphytes) are commensalistic with other trees

5. Keystone Species

a. How could an ecologist identify a keystone species in any given ecosystem?

b. Why are sea stars and beavers considered to be keystone species in their habitats?

6. Primary Succession (3 words or less – condense!)

a. Which types of organisms transform bare rock in to young soil?

b. Where do the mineral and organic components of the new soil come from?

c. What role do mid-successional species such as grasses and wildflowers play in

transforming soil?

d. Why do mid-successional species eventually get displaced by late-succession species?

e. True/false: the number of species present always increases as succession proceeds.

7. Secondary Succession

a. How does secondary succession differ from primary succession?

b. What are some similarities between the progression of species in secondary succession

and in primary succession?

c. Why has the use of the term climax stage fallen out of favor among scientists?

d. True/false: The Opening Story describes a sequence of primary succession

e. True/false: In the Opening Story, Goldenrods are late-successional spcies

8. Aquatic Succession

a. Where does succession occur in the rocky intertidal zone of the Pacific Coast?

b. Describe how lakes become filled in during aquatic succession:

9. Species Richness, Latitude, Time, Theory of Island Biogeography

Influence of this factor on species richness?

What do you think causes this?

Latitude

Time

The older a habitat, the greater its species richness is likely to be; younger habitats have lower species richness

Habitat Size

Larger habitats present more niches; smaller habitats offer fewer resources

Distance from other habitats

10. What does the story of the black-footed ferret illustrate? Why is it important?

Chapter 7 Vocabulary List

Demography Developed countries

Crude Birth Rate (CBR) Developing countries

Crude Death Rate (CDR) Infant mortality

Total Fertility Rate Child mortality

Replacement-level fertility Population pyramid

Age structure diagram Demographic transition

Affluence IPAT Equation

Reading Questions 7A (pg. 179-188)

1. What types of environmental problems are being caused by China’s large population growth?

2. In addition to population growth, economic development is increasing resource consumption in

China. Which do you think plays a bigger role in achieving sustainability: addressing population

growth or economic development?

3. Considering China’s growth, do you think the strict measures taken by the country’s government

to reduce growth (such as the One Child Policy) are justified? Or is this a violation of human

rights?

4. Do you think it is possible for China to meet the needs of its large (and growing) population for

resources without putting it on a path of unsustainable resource consumption? If so, how can

they do it? If not, why can’t they do it?

5. The population and resource problems facing China are playing out all over the world in

developing countries. Do developed countries have an obligation to help solve these problems,

or are they things that each country must address on their own? Explain your answer.

6. What was Malthus’ prediction about the carrying capacity of the Earth, and why was he wrong?

7. What do you think the major constraining limits on human population growth are? (In other

words, what will be the critical limiting resources that determine Earth’s carrying capacity for

humans?)

Demographics

8. Provide the formula for calculating the change in population size over a given period of time:

9. What does the TFR of a country measure, and why is it an important demographic

measurement?

10. Which regions of the world have SHORT life expectancies, which ones have LONG life

expectancies, and what are the major factors that influence this?

11. What information do population pyramids show, and why are they important demographic

information?

Reading Questions 7B (pg 188-198)

1. What is underlying cause of the demographic transition that most countries go through as they

develop?

2. Complete the following chart regarding the demographic transition:

Stage I Stage II Stage III Stage IV

What happens?

Why?

Impact on population?

3. What major factors tend to reduce the number of children families have?

4. Based on the experiences of Thailand, Kenya and China in promoting family planning, what do

you think the key is to reducing population growth in developing countries? Is this goal

beneficial or harmful?

Development, Consumption, IPAT

5. How do the annual population growth rates of developed countries compare to developing

countries?

6. Where is most of the future growth in the human population expected to happen?

7. Why does calculating the per-capita ecological footprint for a country allow us to approximate

the affluence level of the society?

8. What are the 3 terms in the IPAT equation that affect a society’s impact on its environment?

Give an example of how a change in each would cause a change in the society’s impact.

a.

b.

c.

9. How can the technology factor of the IPAT equation work to either increase OR decrease the

impact of a society on the environment?

10. As a country develops economically, its impact on the environment shifts from local to global

scales. Using your knowledge of the industrial revolution, explain why this is.

11. Contrast the types of environmental problems which occur from local environmental impacts

(typically in developing countries) and global environmental impacts (typically from developed

countries).

12. How does the percentage of people living in urban areas in developed countries compare to

developing countries? How is this expected to change in the next 20 years?

13. We find that countries with very low GDPs per capita have little impact on the environment,

then the impact rises as GDP increases, until eventually the impact begins to decrease. What

causes this pattern (low impact rising impact falling impact)?

14. Some environmental scientists have argued that increasing the GDP of developing nations is the

best way to decrease their impact on the environment. Explain why this might work.

15. The status and rights of women varies widely around the world; in some nations, they have surpassed men in educational attainment, while in other countries women remain second-class citizens or victims of violence and poverty. How do women’s rights and societal development interact? Consider demographics, economics, politics, and sustainability in your response.