1. 1) Population: individuals of same species in same general area. Has geographic boundaries and population size. Key traits: density (individuals per unit of area or volume) and dispersion (uniform, clumped, random). 2) Demography: studies changes in population size. Births and immigration (+); deaths and emigration (-). 3) Life histories: affect reproductive output and survival rate, thus population growth. Trade-offs between survival and reproduction. Semelparity (big-bang reproduction), iteroparity (repeated reproduction). 4) Population growth: exponential (J-shaped, idealized, occurs in certain conditions) and logistic (S-shaped. little more realistic, carrying capacity). K-selection. Density-dependent selection. r-selection. Density independent selection. 5) Density-dependent changes in birth and death rates usually slow down population growth rate. Natural populations are characterized by instability due to interaction of biotic and abiotic factors. In some populations they result in regular boom-and-bust cycles.

2. The more, the better; we are buddies and can outcompete other plant species, so our population will always grow. It’s every seedling for itself. There is so much water, soil and sun to go around. If we are many, the population will eventually decline due to competition. The population might decline but never from competition, we would never compete. There are always enough resources. No matter how many we are, the population will always grow. Does the number of seedlings affect population growth ever?

3. 1- Haven’t we seen whales breaching with giant squids? SOME questions from February 10th 2- To what phyla do puffballs belong? 3- Is a forest or grassland considered a uniform distribution 4- When calculating population sizes, do you count migratory species? 5- Do we know the carrying capacity of the world for humans?

4. Chapter 52 Population Ecology Chapter 53 Community Ecology

5. Human Population= 6,275,956,078 (Feb 20 th, 2003) Annual increase: 1963: 2.19% 1984: 1.7% 2005: 1.13% (200,782/day) 2049: 0.47% 6,418,752,524 (Feb 14 th, 2005) Fig. 52.20 pages 1168-1169

6. 1.2% 0.0% 0.9% 0.7% page 1169

7. BELLINGHAM CensusScope

8. sustreport.org World Wildlife Fund for Nature Fig. 52.23 pages 1170-1171

9. Organismal ecology coping Population ecology limiting factors Community ecology interspecific interactions and diversity Ecosystem ecology energy flow and chemical cycling Landscape ecology effects on interactions at lower levels Biosphere ecology global effects

10. Community. All the organisms of all the species inhabiting an area. (assemblage of populations of different species). Community Ecology Key measurements: Relative abundance- Percentage contribution of each species to the total number of individuals in the community. Species richness- Number of species in the community. Species evenness- How individuals are apportioned among the species. Even: All species have same number of individuals. Uneven: Species have very different numbers of individuals. Species diversity- Relates species richness and species evenness. Community properties and structure are given by species composition and species interactions. page 1174

11. What explains the particular species found in each community? Individualistic hypothesis. Species found in same area due to similar abiotic needs. Assemblage by chance. Interactive hypothesis. Species linked due to mandatory biotic interactions. Assemblage not by chance, community functions as an integrate unit. Rivet model. Most species tightly associated with other species. Redundancy model. Most species not tightly associated with one another. Fig. 53.1 pages 1175-1176 For animals What does each hypothesis predict? What hypothesis is supported by data?

12. Regardless of the correct model, be it one of these two or another one, UNDERSTANDING COMMUNITY STRUCTURE REQUIRES UNDERSTANDING INTERACTIONS BETWEEN SPECIES Table 53.1 page 1176

13. Competition. Both species incur a cost by competing for a resource. Important in shaping communities and adaptive evolution. Competitive exclusion principle. Two species cannot coexist if their ecological niches are identical. Ecological niche. Biotic and abiotic resources used by a species; role of the species in the environment. Fig. 53.2 pages 1176-1177

14. If two species have identical niches, one might be driven to extinction or evolve to use a different set of resources. Resource partitioning. Differentiation of niches allowing similar species to coexist. Fig. 53.3 page 1177

15. Predation. One species benefits and the other one incurs a cost. Includes herbivory and parasitism. Important factor in in adaptive evolution: predator adaptations, plant defenses against herbivores, prey adaptations. Also important in shaping communities. wavelength pages 1178-1179

16. Mutualism. Both species benefit from the interaction. Some are obligatory: both species cannot persist without the other; others are facultative: the association is nonessential. funet.fi Tree of Life pages 1180-1181

17. Conifers Ectomycorrhizae Voles Pacific Northwest: Corals, zooxanthellae

18. Commensalism. Only one of the species benefits from the interaction, whereas the other species receives neither a benefit nor incur a cost. Appear to be rare in nature. page 1181

19. COMMUNITY STRUCTURE Species Interactions Competition, Predation, Mutualism, Commensalism Trophic Structure Dominant and Keystone Species Community Organization

20. TROPHIC STRUCTURE Feeding relationships between organisms. Describe species interactions. Food chain- Transfer of food energy all the way until decomposers. Trophic levels- Links in the food chain. Usually four or five. Food web- Branching and interconnected food chains. Fig. 53.10 page 1181

21. ANTARCTIC FOOD WEB Fig. 53.11 page 1182

22. Fish Zooplankton Phytoplankton Proc. Natl. Acad. Sci. 18 Feb 2003 FOOD WEB TUESDAY LAKE, MI