1. Population of Ecology

2. Ecology Study of the interactions of organisms in their biotic and abiotic environments Organism  population  community  Ecosystem  biophsere

3. Demographics of populations Demography – statistical study of a population (density, distribution, growth rate) Population density - # of individuals per unit area (can be misleading) Population distribution – pattern of dispersal across an area (controlled by resources and limiting factors) clumped, random, uniform

4. Population growth Rate of natural growth (r) based on birth and death rate. Biotic potential – highest possible growth rate with unlimited resources.

5. Survivorship curves Probability that newborn will survive to certain ages. Curve I – characteristic of a population in which most individuals survive well past midpoint of lifespan. Ex. Large mammals, humans

6. Curve II – survivorship decreases at a constant rate throughout the life span. Ex. Songbird, small mammals (death is usually unrelated to age) Curve III – most individuals die young. Ex. Insects, fish, humans in less developing countries.

7. Age distribution Age structure diagrams Increasing population  Prereproductive ages is largest, birth rate is higher than death rate. Stable population (bell shape)  Reproductive ages equal prereproductive ages Decreasing population (urn shape)  reproductive ages is larger than prereproductive ages, postreproductive age is largest

8. Population Growth Models 2 patterns of population growth:  Discrete breeding – single reproductive event  Continuous breeding – many reproductive events  Research: not always have to be one or the other.

9. Exponential Growth Number of individuals added each generation increases as the total # of females increases. Lag phase – growth is slow to start Exponential growth phase – accelerated growth J shaped curve

10. Logistic growth S-shaped curve Lag phase, exponential growth phase Deceleration phase – growth slows Stable equilibrium phase – little to no growth, BR = DR

11. Carrying capacity Maximum # of individuals of a species an environment can support. Exponential growth can not continue due to carrying capacity  Resources become scarce  Competition and predation Exponential growth occurs when population size is much lower than carrying capacity. Population stabilizes when carrying capacity is reached.

12. Regulation of population size Density independent factors – those that are not dependent on numbers  Weather, natural disasters Density dependent factors – occur because of population of species  Competition, predation, parasitism Intrinsic factors? – anatomy, behavior have an affect on population?

13. Life History Patterns - Opportunistic r – strategists Small individuals, short life span, fast to mature, many offspring, little/no care for offspring, early reproductive age Bacteria, fungi, insects, rodents, annuals

14. Life History Pattern - Equilibrium K-strategists Large individuals, long life span, slow to mature, few and large offspring, care for offspring, most live to reproductive age Large mammals, birds of prey, long-lived plants

15. Human population growth MDC’s – North America, Europe, Japan, Australia, growth is slow LDC’s – Latin America, Africa, Asia, population rising rapidly Ways to reduce projected population increase:  Strengthen family planning  Education, raising status of women, reduce child mortality  Delay onset of childbearing, wider spacing of births

16. Population Growth and Environmental Impact LCD = population growth in numbers MCD = consume larger proportion of Earth’s resources Average family in North America consumes the amount of resources and produces wastes of 30 people from India.