Ecology - Study of interactions among organisms and their environment

2. Ecology - Study of interactions among organisms and their environment Conservation biology, environmentalism: preservation of natural world

3. Biosphere • Ecosystems • Community • Population ECOSYSTEM LEVELEucalyptus forest COMMUNITY LEVELAll organisms ineucalyptus forest POPULATION LEVELGroup of flying foxes ORGANISM LEVELFlying fox Brain Spinal cord ORGAN SYSTEM LEVELNervous system ORGAN LEVELBrain Nerve TISSUE LEVELNervous tissue CELLULAR LEVELNerve cell MOLECULAR LEVELMolecule of DNA Figure 1.1

4. Population Ecology • Population- how to measure? • Growth rates: J shaped, S shaped • K, r, and reproductive strategies • Human population

5. How are populations measured? • Population density = number of individuals in a given area or volume • count all the individuals in a population • estimate by sampling

6. mark-recapture method depends on likelihood of recapturing the same individual Figure 35.2A

7. The dispersion pattern of a population refers to the way individuals are spaced within their area • Clumped - • Uniform: • Random: no pattern

8. Figure 35.2C

9. How do populations grow? • Idealized models describe two kinds of population growth 1. exponential growth 2. logistic growth

10. A J-shaped growth curve, described by the equation G = rN, is typical of exponential growth • G = the population growth rate • r = the intrinsic rate of increase, or an organism's maximum capacity to reproduce • N = the population size • King’s chess game

11. Figure 35.3A

12. high intrinsic rate of increase 1500 r = 0.06 1000 low intrinsic rate of increase r = 0.02 Population size zero population growth 500 r = 0 negative intrinsic rate of increase r = -0.05 0 0 5 10 15 20 Time (years)

13. K = Carrying capacity is the maximum population size that an environment can support 2. Logistic growth is slowed by population-limiting factors Figure 35.3B

14. K = carrying capacity • The term (K - N)/Kaccounts for the leveling off of the curve • logistic growth curve Figure 35.3C

15. Multiple factors may limit population growth declining birth rate or increasing death rate • The regulation of growth in a natural population is determined by several factors • limited food supply • the buildup of toxic wastes • increased disease • predation

16. About every 10 years, both hare and lynx populations have a rapid increase (a "boom") followed by a sharp decline (a "bust") Figure 35.5

17. Three types of survivorship curves reflect important species differences in life history • Survivorship curves plot the proportion of individuals alive at each age Figure 35.6

18. Evolution shapes life histories • An organism's life history is the series of events from birth through reproduction to death • Life history traits include • the age at which reproduction first occurs • the frequency of reproduction • the number of offspring • the amount of parental care given • the energy cost of reproduction

19. Principles of population ecology may be used to • manage wildlife, fisheries, and forests for sustainable yield • reverse the decline of threatened or endangered species • reduce pest populations • IPM = Integrated Pest Management

20. Integrated pest management (IPM) uses a combination of biological, chemical, and cultural methods to control agricultural pests • IPM relies on knowledge of • the population ecology of the pest • its associated predators and parasites • crop growth dynamics

21. The Spread of Shakespeare's Starlings • In 1890, a group of Shakespeare enthusiasts released about 120 starlings in New York's Central Park

22. Current • Today: over 100 million starlings, spread over N. Amer. 1955 Current 1955 1945 1935 1925 1945 1905 1915 1925 1935 1925 1935

24. The starling population in North America has some features in common with the global human population • Both are expanding and are virtually uncontrolled • Both are harming other species

25. THE HUMAN POPULATION • doubled three times in the last three centuries • about 6.1 billion and may reach 9.3 billion by the year 2050 • improved health and technology have lowered death rates

26. The history of human population growth Figure 35.8A

27. RAPID GROWTH SLOW GROWTH ZERO GROWTH/DECREASE Kenya United States Italy Male Female Male Female Male Female • The age structure of a population is the proportion of individuals in different age-groups Ages 45+ Ages 45+ Ages 15–44 Ages 15–44 Under15 Under15 Percent of population Percent of population Percent of population Also reveals social conditions, status of women Figure 35.9B

28. The ecological footprint represents the amount of productive land needed to support a nation’s resource needs • The ecological capacity of the world may already be smaller than its ecological footprint

29. Ecological footprint in relation to ecological capacity Figure 35.8B

30. Per capita CO2 emissions (metric tons of carbon) Total CO2 emissions (billion metric tons of carbon) 0 1 2 3 4 5 6 0 0.5 1 1.5 U.S. U.S. 5.48 1.49 China China 0.75 0.91 0.39 Russia 2.65 Russia Japan Japan 2.51 0.32 India 0.29 India 0.28

31. What next? Figure 35.8C

32. Figure 2.10x