1. ʕ•ᴥ•ʔ Population Ecology ʕ•ᴥ•ʔ

2. Reproductive Strategies
Organisms have adapted either to maximize growth rates in environments that lack limits or to maintain population size at close to the carrying capacity in stable environments
K-strategists: humans, elephants, cacti, and sharks
Species that reproduce later in life and with fewer offspring whom are most likely to live stay alive until adulthood
R-strategists: most insects, algae, bacteria, rodents, and annual plants
Species that have high reproductive rates in which many offspring die before adulthood

3. R-strategists VS. VS. K-strategists Mature rapidly Mature slowly
Short lived
Long lived
Tend to be prey
Tend to be both predator and prey
Have many offspring and tend to overproduce
Have few offspring
Low parental care
High parental care
Are generally not endangered
Most endangered species are K-strategists
Wide fluctuation in population density (booms and busts)
Population size stabilizes near the carrying capacity
Population size limited by density-independent limiting factors, including climate, weather, natural disasters, and requirements for growth
Density-dependent limiting factors to population growth stern from intraspecific competition and include competition, predation, parasitism, and migration
Tend to be small
Tend to be larger
Type III survivorship curve
Type 1 or II survivorship curve
Examples: most insects, algae, bacteria, rodents, and annual plants
Examples: humans, elephants, cacti, and sharks

4. Three Survivorship Curves
Survivorship curves show age distribution characteristics of species, reproductive strategies, and life history.
I. Late Loss
Reproduction occurs fairly early in life. Most deaths occur at the limit of biological life span. Examples: humans, annual plants, sheep, and elephants.
II. Constant Loss
Individuals in all age categories have fairly uniform death rates. Examples: rodents, perennial plants, and songbirds
III. Early Loss
Death is prevalent for younger members of the species(environmental loss and predation) and declines with age. Examples: sea turtles, trees, internal parasites, fish, and oysters

5. Human Population Size
*The rapid growth of the world’s human populations over the past 100 years has been due primarily to a decrease in death rates.
Some factors include:
Increased food and more efficient distributions that result in better nutrition
Improvements in medical and public health technology
Improvements in sanitation and personal hygiene
Safer water supplies

6. The 3 Surges in Human Population
The first was the use of tools and fire. These new technologies and discoveries allowed them to eat different food and thus, receive a wider variety of nutrients.
The second was the agricultural revolution, when humans began to raise crops. This resulted in larger families because families settled down to care for one another in one spot permanently.
The third was the industrial and medical revolutions within the last 200 years. Medicine made the life expectancy of many people rise significantly which gave them more time to reproduce.

7. Age Structure Diagrams
Determined by birth rate, generation time, death rate, and sex ratios
Large base = greater number of young individuals (potential for increase in population)
Large top of pyramid = population is past reproductive years & indicates slowdown in growth
Different stages of demographic transition have different diagrams
Large family size needed to help with farm labor and to support aging parents

8. Strategies for Sustainability
Educate and empower women → more job opportunities
Higher income from jobs decreases the need for extra children
Education = less children
Provide government family planning services
Improving infant health care

9. Population Characteristics
Population size: expressed as the number of individual organisms present at a given time
Population Density: describe the number of individuals within a population per unit area
Population Distribution: describes the spatial arrangement of organisms within an area

10. Pandemics and Other Diseases
Pandemics- epidemic of an infectious disease that has spread through human populations across a large region.
Can spread from human to human contact or even from animals. They pose a major threat to a large population of people.
Example: Spanish influenza of 1918 to 1919 which killed nearly 20 to 40 million people.
Other illnesses include tobacco-induced problems such as respiratory problems and lung cancer. These problems could affect more people than AIDS, tuberculosis, road accidents, murder, and suicide combined.

11. 4 Stages of Demographic Transition
STAGE 1: PRE MODERN ERA (PRE INDUSTRIAL) Birth Rate: Fluctuated Death Rate: Fluctuated Medicine: Did not exist Food: Fish, squirrel, bears Nature: Natural disasters would lower population Population Size: 300 million
STAGE 2: URBANIZATION (INDUSTRIAL PERIOD)  Birth Rate: High Death Rate: Low Medicine: Became widely available Food: People could grow their own food like wheat to make bread Nature: Able to grow crops to make own food. Resources: Wheat, automobile, gun, cotton gin, house Population Size: 1 billion

12. 4 Stages of Demographic Transition
STAGE 3: MATURE INDUSTRIAL ERA Birth Rate: Drastically drop Death Rate: Drops even more Medicine: Further available Food: Fast food, food from Industrial period, processed Nature: Food able to be grown in farms Resources: Metals, oil, wood, machinery Population Size: 3 billion
STAGE 4: POST INDUSTRIAL ERA Birth Rate: Drop super low Death Rate: Super low Medicine: New medicine advances Food: Processed food, natural food Nature: Food is grown less on farms, most food is processed Resources: Oil, wood, metals, machinery Population Size: 7 billion

14. Hunger -25% of world population is malnourished
Several factors contribute to malnutrition
-Poverty
-droughts
-political instability (wars)
-Advances in the green revolution have not fixed world hunger
-Incentives to sell food for higher prices

15. Disease and Economic Impact
AIDS Worldwide million people have died
- predicted in 25 years aids could kill 31 million people in India, 18 in China
-Higher Mortality rates = smaller skilled labor force
-smaller tax base
-AIDS results in the loss of income and increased cost of medicare