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Population BiologyHuman Populations

28 February 200721st class meeting

Environmental Biology (ECOL 206)University of Arizona, spring 2007

Kevin Bonine, Ph.D.Anna Tyler, Graduate TA

(Exam Two in 1 week)

READINGS, Wednesday 28 Feb: Human Populations (Miller chapter)Fri 02 March: SDCP, Biosphere Reserves

Lab 28Feb/02Mar: Meet AT VANTumamoc HillSee reading assignment and handout on webpageLab 07/09 Mar: No lab(work on creativity projects!)

http://eebweb.arizona.edu/courses/Ecol206/206_Page2007.html

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Survivorship Curves(proportion surviving from one age to the next)

Age Class

Sur

vivo

rshi

p Life Expectancy

&

Survivorship

Type I - Most live to old age and die - humansType III – Very high juvenile mortality - fish

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3Ricklefs 2001

Life Table

4Cunningham et al. 8th Edition

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Population Biology and Conservation

- MVP (minimum viable population)

- PVA (population viability analysis)

- ESU (evolutionarily significant unit)

- Founder Effect

- Fragmentation

- Source & Sink

- Metapopulations

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Metapopulation:

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Hydrothermal Vents Lowland Leopard Frogs(thanks to Don Swann)

Metapopulation:

8

5

9

10

4 km

Distribution of Lowland Leopard Frogs in Rincon Mountains, 1996-2001

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Metapopulation Dynamics

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8

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Chytrid Fungus

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Human Population

Miller 2003

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19Ricklefs 2001

Ricklefs 2001

Human Population Growth

Exponential Growth

LogisticGrowth

Ricklefs 2001

VanDyke 2003

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Exponential Growth N = N0ekt

N = future population size at next time interval

N0 = population size at beginning of time interval

e = 2.71828 (base of natural logarithms)

k = rate at which population increases over time interval

t = number of time intervals (usually years)

If k = 0.0136 (1.36% annual increase), and N0 = 6.2 billion

what will population be in 20 years?

N = (6.2x109) x e(0.0136x20)

N = 8.14x109 (8.14 billion)

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Exponential GrowthDoubling Time

N = N0ekt

Td = doubling time

2N0 = N0ekTd

ln 2 = kTd

Td = ln2/k

Td = 0.693/k

Td = 0.693/(R/100)

Td = 69.3/R ~ 70/R

R = growth rate

therefore k=R/100

(e.g., R = 1.36%)

If R = 10% thenTd = 70/10 = 7 years

If R = 1.36% thenTd = 70/1.36 = 51.5 years

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Globally Today:

2.3 people born/ second

219,000 people born per day

Population Simulation7 minutes

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Miller, 2003

Role of Developing Countries

2.6

2.1

1.7

Miller, 2003your Fig 5-2

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Miller, 2003

Pop. of Developing Countries(Consumption?)

Fertility Rates have declined

Miller, 2003

but...

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Miller, 2003your Fig 5-7

Age Structure Diagrams- note age of reproduction- currently 30% under 15 (=1.7 billion)

26Ricklefs 2001

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Population Size

- Birth, Death, Migration

- Birth rate- Crude Birth Rate (per 1,000)

- Death rate- Crude Death Rate (per 1,000)

-Migration-Immigration-Emigration

- Rate of Population Change = birth rate - death rate

Miller, 2003your Fig 5-1

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Birth ratesandDeath rateshave fallen

But…- 216,000 new people/day- 1.4 billion live on <$1/day

- US 288 million to571 million in 2100

Miller, 2003

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- Replacement Level Fertility = 2.1 – 2.5

- Total Fertility Rate (over lifetime of woman)1.6 in developed3.1 in developing(2.8 global average)

- Factors that affect birth rates (p. 80 Miller 2005):1. Children in Labor Force2. Urbanization3. Cost to raise and educate4. Female education and employment5. Infant Mortality Rate6. Age at first reproduction7. Availability of pension/social security8. Availability of abortions9. Birth control availability10. Religious and cultural beliefs

Birth and Fertility

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4. Female education and employment

“For poor women the only holidayis when you are asleep.”

Women:- Do 2/3 of the work- 10% of the income- own 0.01% of the property- 70% of the world’s poor- 2/3 of the world’s illiterate(page 87 Miller 2005)

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- Big contributor to population growth

1. Increased food supplies2. Better nutrition3. Medical Technology

immunizations, antibiotics4. Sanitation and Hygiene5. Safer Water

Decreased Death Rates

Infant Mortality Rate60/1,000 vs. 7/1,000

Life Expectancy65 vs. 76 (67 avg.)

(ex. India, China, Thailand p. 87 Miller 2005)

32Miller, 2003your Fig 5-9

U.S. PopulationExample(baby boom)

Miller, 2003

Miller, 2003

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Demographic Transition

Miller, 2003your Fig 5-10

harshMost developingcountries

Much of Europe

Mostdevelopedcountries(and U.S.)

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Hall et al. 1994.The environmental consequences of having a baby in the United States. Population and Environment 15(6):505-524

Assumptions: One child, to age 75, average American consumption, born 1990s

Looked at 100 impacts in 5 categories,

1. Waste2. Mineral consumption3. Energy consumption4. Ecosystem alteration (Forest, Wetlands, Water)5. Food consumption

Environment and human quality of life

Class project at SUNY

(as well as extinction of species and indigenous cultures)

Ecological Footprint

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Hall et al. 1994. The environmental consequences of having a baby in the United States. Population and Environment 15(6):505-524

Lifetime per capita:

WASTE:1,000,000 kg atmospheric

10,000,000 kg liquid1,000,000 kg solid

CONSUME:700,000 kg minerals

4,000 barrels of oil (energy equivalent)25,000 kg major plant foods28,000 kg animal products (2,000 animals)

162,000 cubic m water0.84 hectares of forest

-5,430 kg of fertilizer; 18,675 eggs; 1,654 chickens-95 Liters of liquid waste per roll of film used-Each dollar spent results in 0.5 L oil extracted and burned

Ecological Footprint

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Killing the Natives, Chapter 3

U.S.: 4% global population25% fossil fuels>25% cars50% advertising spending

Goods vs. Bads

$80 billion on shoes, jewelry, watches$65 billion on higher education

Americans since 1950 have consumed more than all in history preceding

# indivs/house dropping in US

Jimmy Carter – malaise speech, reduce consumption…Reagan