Unit IV -Population Dynamics

Size– Increased by

– Decreased by•

– Calculations

r = (b – d) + (i – e)

Local Population Changes

Global Population Changes

DensityWhat is it?

Does the predator or the prey control it?

Density Independent Factors

Density Dependent Factors

Maximum Population Sizes

Environmental Limits

Carrying Capacity (K)

Growth Curves

S-CurveLogistic Curve

J-CurveExponential Growth

Boom-or-bust populations

J-CurveBoom-or-bust populations

J-CurvePredator-Prey Dynamics

DispersionWhat is it?

What affects it?

Age Distribution• Based on:

how many individuals are reproductive and how long they stay that way.

• R-Strategists – R=Reproductive Potential–

• K-Strategists– K= Carrying Capacity

Age DistributionSurvivorship Curves

Indicate trends in populations related to the # of individuals at each age.Late Loss (Type I)

Constant Loss (Type II)

Early Loss (Type III)

Age DistributionSurvivorship Curves

Human Population Growth

Demography

Agricultural Revolution

Industrial Revolution

Number of Years to Add One Billion People to the World Population

Global Pop.

Date Achieved

Years Required

1 billion 1800 All of human history

2 billion 1930 130

3 billion 1960 30

4 billion 1974 14

5 billion 1987 13

6 billion 1998 11

7 billion 2011 13

Human Population Growth

Human Population Growth

Current world population is ~ 7 billion

7,569,861,660 (Sept 2017 est)

Current world population growth rate is 1.11%

The growth rate is declining, but the population is still increasing.

Projections for 2050

Low = 7.8 billion

High = 10.8 billion

Most likely = 9.2 billion

Human Population Growth

World’s Most Populous Countries

1. China – 1.379 billion – 0.46%

2. India – 1.281 billion – 1.2%

3. USA – 326 million – 0.73%

4. Indonesia – 260 million – 1.17%

5. Brazil – 207 million – 0.83%

6. Pakistan – 204 million – 2.07%

7. Nigeria – 190 million – 2.63%

8. Bangladesh – 157 million – 1.19%

9. Russia – 142 million – -0.01%

10. Mexico– 124 million – 1.27%

Human Population Growth- 2012

World’s Fastest Growing Nations

5. Qatar – 2.1 mil – 3.58%

4. Jordan – 7.9mil – 3.86%

3. South Sudan – 11.5mil – 4.12%

2. Zimbabwe – 13.8mil – 4.36%

1. Lebanon – 5.9mil – 9.37%

World’s Fastest Shrinking Nations

5. Latvia – 2.1mil – -0.64%

4. Ukraine – 44.3mil - -0.64%

3. Estonia – 1.2mil - -0.68%

2. Bulgaria – 6.9mil - -0.83%

1. Moldova – 3.6mil - -1.02%

*Syria – 17.9mil - -9.73%

Demographic Transition

Pre-Industrial Stage

Transitional Stage

Industrial Stage

Post-Industrial Stage

Carrying Capacity of the PlanetWhat is it?

Humans vs. Other Animals

Population Size Factors

Family Planning

Role of Females

Cultural and Religious Beliefs

Population Size Factors

Cultural TraditionsCulture influences and control individuals’ behaviors

Population Size Factors

Social & Economic Status of Women

Gender inequality is common worldwide

Population Size Factors

Social & Economic Status of Women

Women with more education tend to

Population Size FactorsFamily Planning

Government Policies

ChinaIncentives to promote later marriages and 1 child families

India1950 - 1st national government-sponsored family planning

1976 – Incentives for sterilization

Recently has focused on education

Human Health

Two main indicators of human health

Vary GREATLY between developed and developing nations

Human Health - Developed

Average Life Expectancy

Leading causes of death

Most premature deaths are caused by lifestyle choices

Poor diet, lack of exercise, smoking, obesity

Human Health - Developing

Average Life Expectancy

Biggest issues

Childhood mortality is high

Diseases and IllnessesNon-transmissible Diseases

Transmissible Diseases

Diseases and IllnessesOld World (Reemerging) vs. New World (Emerging) Diseases

Developed Nations~8% of deaths are from infectious disease

1 doctor for every 500 people

Developing Nations~40% of deaths are from infectious disease

In E. Africa - only 1 doctor for every 600,000 people.

World’s 7 Deadliest Infectious Diseases

Toxicology

What is it?

Toxicity

Acute

Chronic

Factors Affecting Toxicity

Movement and Distribution InfluencesGenetic Makeup

Solubility

Persistence

Frequency

Biomagnification/Bioaccumulation

Factors Affecting Toxicity

Determined by LD50

– Level at which a chemical kills 50% of the test populations with a single dose within 14 days.

LD = Lethal Dose

50 = 50% mortality of the test population

– AKA: median lethal dose

Factors Affecting Toxicity

Dose

Response

Dose-Response Curve

Factors Affecting Toxicity

Risk Assessment Limitations

Laboratory Testing Limitations:

Lab rats are different from humans.

May not identify what other chemical exposures occurred or what habits a person has.

May not show the effects of chemical interactions.

Testing may be too costly and slow to use on every chemical.

Groupings of Toxic ChemicalsMutagens

Teratogens

Carcinogens

Neurotoxins

Asphyxiates

Allergens

Risk Assessment

Risk

Probability that a particular adverse effect will result from some exposure or condition.

Four primary steps

Urban AdaptationsUrban Areas

ProsBetter access to education, health care, jobs.Reduce destruction of wildlife habitats, protects biodiversity.

ConsHigher concentrations of pollutants and infectious diseases.Infrastructures are more expensive to repair.