1. Introduction to Ecology and Human Population Growth

2. IN: Could there ever be too many people on earth? Why or why not? Out: How could overcrowding in another part of the world affect you?

3. I. Ecology A. Study of the relationship between living organisms and their physical environment Greek b. “oikos” = house a.“logia”=study of What is ecology?

4. A. Biosphere a. life in a thin layer b. area of earth where life exists; living globe c. about 13 miles of water and air II. Ecological Organization

5. B. Biome a. large, worldwide group of related ecosystems with similar climate, plants, and animals

6. C. Ecosystem a. unit that includes all the living and nonliving parts of an environment in an area

7. D. Community a. all populations in a common area that interact

9. E. Population A. group of organisms that live in the same area that can breed

10. F. Organism : any living biological entity, such as an animal, plant, fungus, or bacterium

11. G. Species = a group of organisms capable of interbreeding and producing fertile offspring. For example, these happy face spiders look different, but since they can interbreed, they are considered the same species: Theridion grallator.

12. III. Population ecology – the study of factors that cause a population to change in size. A. Population size - (N) the total number of individuals within a defined area at a given time.

13. Types of population Distribution B. Population distribution - a description of how individuals are distributed with respect to one another.

14. C. Population Density - The number of individuals in a population in a certain area is known as the population density.

15. D. Population Density- the number of individuals per unit area at a given time. a. Density dependent factor- a factor that influences the probability of survival and reproduction in a manner that depends on the size of the population. 1.competition 2.predation 3.parasitism 4.disease

16. b. Density independent factor - a factor that has the same effect of the probability of survival and reproduction regardless of the population size. 1.Temperature 2.natural disasters (floods, earthquakes, fires) 3.pollution

17. E. Population Sex Ratio-the ratio of males to females in a given population. In most sexually reproducing species, this should be close to 50:50. Look at the table above. Use the ratios given for different ages and tell me who lives longer.