1. Population Ecology Chapter 4:

2. Main Idea: Human population growth changes over time. Section 1 Characteristics of Populations Population Limiting Factors Section 2 Human Population Growth Trends in Growth

3. Populations Groups of the same species, living in the same area, at the same time!

4. Population Characteristics 1. Population Density (# per unit area) How many are in a given amount of space? Population density is highest when resources are abundant and when body size is small.

5. 2. Spatial Distribution Dispersion is the pattern of spacing within an area. Uniform Random clumped Affected by availability of resources

7. Population Limiting Factors (2) 1. Density independent factors: Any factor in the environment that does not depend on the number of members in the population per unit area. (the density!) Usually abiotic, including natural phenomena and weather events like drought, floods, extreme heat or cold.

8. Example of density independent: Flooding Few lemmings Lots of lemmings

9. 2. Density dependent factors Any factor in the environment that depends on the number of members in a population per unit area. (the density!) Usually biotic such as predation, disease, parasites, competition.

10. Example of density dependent: predation

11. Predation Graphs of 2 populations often show a rise and fall in population size demonstrating the dependence on one another

13. Number of nesting sites: density dependent

14. Population Growth Rate (4 terms) How fast a population grows or increases in size. 1. Natality = # of organisms born (birthrate) 2. Mortality = # of organisms that die

15. 3. Emigration (exit) The number of individuals moving away from a population

16. How does emigration affect a population? Initially it makes the population smaller due to the loss of organisms. BUT, less competition, more resources could increase the birth rates and eventually allow the population to have a growth rate increase.

17. 4. Immigration (to come in) The number of individuals moving into a population.

19. Types of Population Growth: Exponential (J curve) Logistic (S curve)

20. No limits= exponential growth Lots of food, lots of space, no competition, no predators …growth will go on and on…

21. Exponential growth J curve

24. Logistic Growth S curve Growth starts with a lag phase, grows rapidly, but reaches the carrying capacity and stops increasing. Fewer births than deaths or emigration exceeds immigration.

25. Logistic Growth S curve

26. Carrying Capacity The maximum number of individuals in a species that an environment can support for the long term. Limited by energy, water, oxygen, and nutrients available

27. How does the carrying capacity affect the reproductive rates? Ex: How will the reproductive rate be affected if the population is below the carrying capacity?

28. What does this look like on a graph?

29. Reproductive Patterns: r-strategy k-strategy

30. What if you live in an environment that fluctuates (changes)? r – strategy: Have lots of babies, don’t take care of them! Doesn’t take much energy. Ex: rabbits, fruit flies, locusts

32. What if you live in a stable environment? k-strategy: Have a few babies and take very good care of them. Takes a lot of energy! Ex: kangaroos, humans, polar bears, elephant

34. r Unstable environment, density independent K Stable environment, density dependent interactions small size of organismlarge size of organism energy used to make each individual is low energy used to make each individual is high many offspring are producedfew offspring are produced early maturity late maturity, often after a prolonged period of parental care short life expectancylong life expectancy each individual reproduces only once individuals can reproduce more than once in their lifetime survivorship pattern in which most of the individuals die within a short time but a few live much longer survivorship pattern in which most individuals live to near the maximum life span

35. Section 2 Human Populations

36. Demography: Human population size Density Distribution Movement Birth and death rates

38. Age Structure Diagram

39. Current Growth Rate = 80 million people per year Rate of growth is slowing. Decline due to disease (AIDS), birth control, education Zero population growth: Births = deaths

42. Human carrying capacity? What are we using the energy for?

44. Chapter 5 Biodiversity and Conservation

45. Section 1: Biodiversity Types of Biodiversity Importance of Diversity Section 2: Threats to Biodiversity Types of Extinctions Specific Threats Section 3: Conserving Biodiversity Natural Resources Specific Protections

46. Types of Biodiversity (4) 1. Biodiversity: variety of life in an area 2. Genetic Diversity: variety of genes in a population 3. Species Diversity: # of different species and abundance of each This increases as you move toward the equator where the environment is more stable.

47. Increased diversity near the equator!

48. 4. Ecosystem Diversity: variety of ecosystems in the biosphere

49. Importance of Diversity Economic Value: clothing, food, energy, medicine Aesthetic Value: beauty Inherent Value: Protect biodiversity just because we should

50. Section 2 Threats to Diversity 2 types of Extinction: Background extinction: gradual, natural process Mass Extinction: large scale extinction, accelerated rate

51. 99% of all species that ever existed on Earth are now extinct. These extinctions mark some of the great transitions in life, when new groups of species got the opportunity to take over the niches of old ones. Mammals, for example, only dominated the land after giant dinosaurs vanished 65 million years ago in the Cretaceous-Tertiary extinction. We humans, in other words, are the children of extinctions. http://evolution.berkeley.edu/evolibrary/article/history_08

52. TODAY: Current rate of extinction is 1,000 times the normal rate. 1/3 to 2/3 of all plants and animal species will be extinct by the year 2100. Many are on islands (can’t escape). Humans are changing conditions on earth faster than organisms can adapt (evolve).

53. Specific Threats: Overexploitation: hunting, fishing Habitat Loss: –human encroachment –deforestation Habitat Fragmentation: roads, subdivisions, pipelines

55. Pollution Biological Magnification: when the apex predator dies from accumulated toxins Ex: DDT (pesticide) and birds eggs

57. Acid Rain: due to pollution by humans! Compounds react in the atmosphere to produce sulfuric and nitric acid.

59. Eutrophication: Excess nutrients flow into aquatic ecosystems resulting in algal blooms. Oxygen used up, fish die!

61. Introduced (invasive) species: Species that are not native to the area. Introduced species are a greater threat to native biodiversity than pollution, harvest, and disease combined. Florida: Fire Ant Hydrilla Ball Python Mimosa Lantana Cuban Tree Frog Green iguanas

63. Spice berry hydrilla Mimosa tree

64. The End