Ecology

1. Ecology Campbell, Chapters 50-54

2. Ecology v. Environment • Hierarchy of Ecology • biosphere • ecosystem • community • population • organismal

3. Biotic and Abiotic Factors • components of the environment • biotic • other species may affect one species and its distribution • abiotic • temperature • water • sunlight • Wind • rocks and soil

4. Population Ecology • Density • mark and recapture method • line intercept method • point count method • Distribution • clumped • uniform • random

5. Age Distribution • distribution of males and females in each age group of a population • used to predict future population growth

6. Survivorship • mirrors mortality • expressed in survivorship curves • plots surviving individuals at different age groups • three types of survivorship curves • late loss (Type I) • constant loss (Type II) • early loss (Type III)

7. Population Dynamics: Exponential Model • population lives in an area with no environmental limitations • example • # of births over one year is 500 and # of deaths over one year is 50 B = number of births in time period D = number of deaths in time period

8. Population Dynamics: Exponential Model • per capita rate of increase • average number of births and deaths calculated as rates • J curve • exponential growth

9. Population Dynamics: Exponential Model • example • 10,000 birds in a population • 1500 births and 500 deaths per year • 1500/10,000 - 500/10,000 = .10 or 10% • expressed by stating there is a 10% increase per bird per year

10. Population Dynamics: Exponential Model • measures optimal population growth • rmax = intrinsic rate of increase • example • if N=500; r=.05 Calculate the intrinsic rate of increase

12. Population Dynamics: Logistic Growth Model • size of a population is limited to: • intrinsic rate of increase • environmental resistance • includes limitations the environment imposes on birth rate and death rate in a population • food • space • predation • Parasitism • carrying capacity (K) determined by • renewable resources like water, nutrients, and light • nonrenewable resources such as space

13. Population Dynamics: Logistic Growth Model • logistic population growth • r decreases as N increases • K-N tells us # of individuals population can accommodate • S curve

14. Logistic Growth Model and Life Histories • K-selected • equilibrial populations • live at density near limit imposed by resources • r-selected • opportunistic populations • live in environments where little competition is present

15. Density Influence on Birth and Death Rates • density independent • unrelated to population size • most important are • weather • Climate • density dependent • increase effectiveness as population density increases • especially affects long lived organisms • include • predation • parasitism • competition

16. Human Population Growth • J curve growth • grows at a rate of about 80 million yearly (r=1.3%) • Why doesn’t environmental resistance take effect? • altering their environment • technological advances • the cultural revolution • the agricultural revolution • the industrial-medical revolution

17. Community Ecology • competition • predator-prey • symbiosis • mutualism • commensalism • parasitism • amensalism • species richness • relative abundance • species diversity

18. Competition • intraspecific competition • interspecific competition • Competitive exclusion principle

19. Predator-prey Interactions • one species eating another • herbivory • carnivory • parasitism • cannibalism • predators are agents of natural selection • animal defenses against predators • hiding or escape • mimicry • adaptive coloration

20. Mimicry • Batesian mimicry

21. Mimicry • Müllerian mimicry

22. Mimicry • aggressive mimicry

23. Adaptive Coloration • cryptic coloration

24. Adaptive Coloration • deceptive coloration

25. Adaptive Coloration • aposematic coloration

26. Symbiosis • involves • host • symbiont • 3 divisions • mutualism • commensalism • parasitism Mutualism - lichens

27. Symbiosis • involves • host • symbiont • 3 divisions • mutualism • commensalism • parasitism Commensalism – sea slug and chloroplasts

28. Symbiosis • involves • host • symbiont • 3 divisions • mutualism • commensalism • parasitism Parasitism – Chagas’ Disease

29. Coevolution • reciprocal evolutionary change • e.g. flower shape and pollination • creates a “balance of nature”

30. Moderator of Competition • keystone species • removal dramatically alters the environment • influences species diversity

31. Trophic Structure • feeding relationships • trophic levels • primary producers • primary consumers (herbivores) • secondary consumers (primary carnivores) • tertiary consumers (secondary carnivores) • detritovores • omnivores • food chain vs. food web

32. Food Chain v. Food Web

33. Ecological Succession • structural change in a community and its nonliving environment over time • typically occurs as a result of some environmental disturbance • 2 forms • primary succession • begins in a lifeless area with invaders called pioneers • may proceed to a stable climax community • vary according to geography, climate, etc • secondary succession • occurs in an existing community where a disturbance has occurred

36. Ecosystem Processes • Production • Consumption • Decomposition Trophic Relationships exhibit all 3 processes • autotrophs produce • heterotrophs consume • detritovores and decomposers recycle and decompose

38. Production: Energy Flow • light energy • about 1% of sun’s energy used for life • converted via photosynthesis • How do we measure the amount of energy incorporated by producers? • primary production

41. Consumption: Energy Flow • ecological efficiency • 10% on average • energy pyramid • biomass pyramid

44. Nutrient Cycles • Biogeochemical cycles • materials move through biotic and abiotic portions • reservoir

45. Biogeochemical Cycles • Be able to answer the following questions about each biogeochemical cycle • 1. What is the reservoir? • 2. How does the nutrient enter the biotic portion of the cycle? • 3. How is the nutrient returned to the reservoir?

50. Biological Magnification • toxic substances accumulate in higher concentrations as trophic levels increase • toxin is usually not biodegradable • result of inefficiency of energy transfer