Upload
others
View
10
Download
0
Embed Size (px)
Citation preview
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.