Global ecology Landscape ecology Ecosystem ecology Community ecology Population ecology Organismal ecology 1 Atmosphere Low angle of incoming sunlight 90 N (North Pole) 23.5 N (Tropic of Cancer) Sun overhead at equinoxes 0 (Equator) 23.5 S (Tropic of Capricorn) Low angle of incoming sunlight 90 S (South Pole) Latitudinal variation in sunlight intensity 2
66.5 N (Arctic Circle) 60 N Westerlies 30 N Northeast trades 0 Southeast trades 30 N 0 Descending dry air absorbs moisture. Ascending moist air releases moisture. 30 S Westerlies 60 S 66.5 S (Antarctic Circle) Global air circulation and precipitation patterns 3 March equinox December solstice Constant tilt of 23.5 June solstice 60 N 30 N 0 (equator) 30 S September equinox 4
Labrador Current California Current PACIFIC OCEAN Gulf Stream ATLANTIC OCEAN 5 Air flow Leeward side of mountains Mountain range Ocean 6
30 N Tropic of Cancer Equator Tropic of Capricorn 30 S Tropical forest Savanna Desert Chaparral Temperate grassland Temperate broadleaf forest Northern coniferous forest Tundra High mountains Polar ice 7 Desert Temperate grassland Tropical forest Annual mean temperature ( C) 30 15 0-15 0 Temperate broadleaf forest Northern coniferous forest Arctic and alpine tundra 100 200 300 400 Annual mean precipitation (cm) 8
A tropical rain forest in Costa Rica 9 A savanna in Kenya 10
Organ Pipe Cactus National Monument, Arizona 11 An area of chaparral in California 12
A grassland in Mongolia 13 A coniferous forest in Norway 14
A temperate broadleaf forest in New Jersey 15 Dovrefjell National Park, Norway 16
A basin wetland in the United Kingdom 17 An oligotrophic lake in Alberta, Canada 18
A headwater stream in Washington 19 A rocky intertidal zone on the Oregon coast 20
A coral reef in the Red Sea 21 Open ocean near Iceland 22
A deep-sea hydrothermal vent community 23 Littoral zone Limnetic zone Photic zone Benthic zone Aphotic zone Pelagic zone Zonation in a lake 24
Why is species X absent from an area? Does dispersal limit its distribution? Yes No Area inaccessible or insufficient time Do biotic factors (other species) limit its distribution? Water, oxygen, salinity, ph, soil nutrients, etc. Temperature, light, soil structure, fire, moisture, etc. Chemical factors Physical factors No Yes Predation, parasitism, competition, disease Do abiotic factors limit its distribution? 25 Births Deaths Births and immigration add individuals to a population. Deaths and emigration remove individuals from a population. Immigration Emigration 26
(a) Clumped (b) Uniform (c) Random 27 Number of survivors (log scale) 1,000 100 10 1 0 I II III 50 Percentage of maximum life span 100 28
Population size (N) 2,000 1,500 1,000 500 dn dt = 1.0N dn dt = 0.5N 0 0 5 10 15 Number of generations 29 Population size (N) K = carrying capacity dn = r max N (K N) dt K Number of generations 30
31 2,000 Exponential growth dn = 1.0N dt Population size (N) 1,500 1,000 K = 1,500 Logistic growth dn = 1.0N (1,500 - N) dt 1,500 500 Population growth begins slowing here. 0 0 5 10 15 Number of generations 32
Dandelions grow quickly and release a large number of tiny fruits. The Brazil nut tree (above), produces a moderate number of large seeds in pods (left). 33 When population density is low, b > m. As a result, the population grows until the density reaches Q. When population density is high, m > b, and the population shrinks until the density reaches Q. Birth or death rate per capita Density-independent death rate (m) Equilibrium density (Q) Density-dependent birth rate (b) Population density 34
Competition for resources 35 Predation 36
Disease 37 Toxic wastes 5 µm 38
Territoriality 39 Intrinsic factors 40
50 2,500 Number of wolves 40 30 20 Wolves Moose 2,000 1,500 1,000 Number of moose 10 500 0 1955 1965 1975 1985 1995 2005 Year 0 41