1. AP & Pre-AP Biology Serrano H. S.
Ecology
AP & Pre-AP Biology
Serrano H. S.

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

51. Nitrogen Cycle

52. Water Cycle

53. Carbon Cycle

54. Human Impact Greenhouse effect Ozone depletion Acid rain Deforestation
Pollution
Species extinction