Ecology

1. Ecology

2. Ecology • Scientific study of the interactions between organisms and their environment

3. Levels of Study • Organism • Individual • 1 turtle

4. Levels of Study • Population • Individuals of the same species living in the same area • All the turtles of the same species

5. Levels of Study • Community • All the organisms living in an area • All the turtles, plants, insects, algae, bacteria

6. Levels of Study • Ecosystem • All the organisms and all the abiotic factors • All the organisms & the soil, water, gases, minerals

7. Levels of Study • Biosphere • All the organisms & all the abiotic factors on Earth • Earth

8. Abiotic Factors • Nonliving • Temperature • Climate • Soil type • Rainfall • Gases • Minerals

9. Biotic Factors • Living • Predators • Parasites • Herbivores • Carnivores • Decomposers

10. Biomes • Tropical rainforest • Tall trees • High temperature • Heavy rainfall

11. Biomes • Savannas • Tropical • Grasslands • Scattered trees • High temperature • Less rainfall than tropical rain forest

12. Biomes • Temperate grasslands • Grasses • Seasonal droughts • Occasional fires • Lower temperature & less rainfall than savannas

13. Biomes • Deciduous forests • Deciduous trees • Oak, maple • Warm summers • Cold winters • Moderate rainfall

14. Biomes • Taiga • Coniferous forests • Pines & firs • Cold winters • Heavy snowfall

15. Biomes • Tundra • Grasses & sedges • Very cold winters • Permafrost • High winds • Little rain

16. Population Characteristics • Density • Number of individuals per unit area or volume

17. Population Characteristics • Dispersal Patterns • Spacing between individuals • Clumped • Uniform • Random

18. Population Characteristics • Dispersal Patterns • Clumped

19. Population Characteristics • Dispersal Patterns • Uniform

20. Population Characteristics • Dispersal Patterns • Random (ferns)

21. Population Characteristics • Demographics • Study of vital statistics • Age structure • Groupings by age • Graphed • Sex ratio • % of females compared to males

22. Population Characteristics

23. Survivorship Curves • Graph of # of survivors vs. relative age

24. Survivorship Curves • Type I • Most survive to middle age • Humans

25. Survivorship Curves • Type II • Likelihood of death same at any age • Squirrel

26. Survivorship Curves • Type III • Most die young • Oyster

27. Limiting Factors • Prevent population from reaching biotic potential • Types • Density dependent • Density independent

28. Limiting Factors • Density dependent • Effect becomes more intense with increased density • Examples • Parasites & diseases • Competition for resources • Toxic effect of waste products • Predation

29. Limiting Factors • Density independent • Occur independently of density • Examples: • Natural disasters • Climate extremes

30. Population Growth Models • Exponential Growth • Change in # of individuals (N) over time (t) is equal to the growth rate (r) times the number of individuals (N)

31. Population Growth Models • Exponential Growth • J-shaped curve

32. Population Growth Models • Logistic Growth • When limiting factors restrict size of population to carrying capacity • Carrying capacity (K) = max. # of individuals of a population that can be sustained by the habitat

33. Population Growth Models • Logistic Growth • Sigmoid (S) shaped curve

34. Life-History Strategies • r-selected species • Exhibit rapid growth (J-curve) • Examples – grasses, insects • Characterized by opportunistic species • Quickly invade habitat • Quickly reproduce • Then die • Produce many offspring that are small, mature quickly, require little parental care

35. Life-History Strategies • k-selected species • Population size remains relatively constant • Example - humans • Produce small number of relatively large offspring that require extensive parental care • Reproduction occurs repeatedly during lifetime

36. Community Interactions • Interspecific Competition • Competition between different species • When 2 species compete for same resources one will be more successful • To survive, the less successful species • Must use slightly different resources • Must use resources during different time of day

37. Community Interactions • Predation • Any animal that totally or partly consumes a plant or animal • True predator kills and eats another animal • Parasite lives in and off a host • Herbivore is an animal that eats plants

38. Community Interactions • Symbiosis • Two species that live together in close contact • Types • Mutualism • Commensalism • Parasitism

39. Community Interactions • Mutualism • Both species benefit from relationship • Examples • Bacteria in root nodules • Lichens – algae & fungus living together

40. Community Interactions • Commensalism • One species benefits while the other is neither harmed nor helped • Examples • Birds building nests in trees • Egrets that eat insects around cattle

41. Community Interactions • Parasitism • One species benefits while the other is harmed • Examples • Tapeworm inside animal • Ticks on dog

42. Ecosystems – Trophic Levels • Primary producers • Plants • Photosynthetic bacteria • Algae

43. Ecosystems – Trophic Levels • Primary consumers • Herbivores • Eat producers

44. Ecosystems – Trophic Levels • Secondary consumers • Carnivores • Eat primary consumers (herbivores)

45. Ecosystems – Trophic Levels • Tertiary consumers • Secondary carnivores • Eat secondary consumers

46. Ecosystems – Pyramids • Pyramid of numbers • Most = producers • Least = top level consumers

47. Ecosystems – Pyramids • Pyramid of energy • Most = producers • Least = top level consumers

48. Ecosystems – Pyramids • 10% rule • Only 10% of energy available at each trophic level is converted into new biomass at the next level

49. Ecosystems – Food Chain

50. Ecosystems – Food Web