Ecology the scientific study of the interactions between organisms and the environment

Organisms and the Environment Abiotic factors nonliving components Biotic factors living components collectively called the biota Biosphere global ecosystem sum of all the planet’s ecosystems

LE 50-7 New areas occupied Year 1996 1989 1974

Biotic Factors Biotic factors that affect the distribution of organisms may include: Interactions with other species Predation Competition

August 1982 February 1983 August 1983 February 1984 LE 50-8 100 Sea urchin Both limpets and urchins removed 80 Only urchins removed 60 Seaweed cover (%) Limpet 40 Only limpets removed 20 Control (both urchins and limpets present) August 1982 February 1983 August 1983 February 1984

Abiotic Factors Abiotic factors affecting distribution of organisms: Temperature Water Sunlight Intensity Photoperiod Wind Rocks and soil Mineral composition pH

Climate Four major abiotic components of climate: Temperature Water Sunlight Wind Climate = prevailing weather in an area

Low angle of incoming sunlight LE 50-10a North Pole 60°N Low angle of incoming sunlight 30°N Tropic of Cancer Sunlight directly overhead at equinoxes 0° (equator) Tropic of Capricorn 30°S Low angle of incoming sunlight 60°S South Pole Atmosphere

Seasonal variations of light and temperature increase steadily toward the poles

LE 50-10b March equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness. 60°N 30°N June solstice: Northern Hemisphere tilts toward sun; summer begins in Northern Hemisphere; winter begins in Southern Hemisphere. 0° (equator) 30°S December solstice: Northern Hemisphere tilts away from sun; winter begins in Northern Hemisphere; summer begins in Southern Hemisphere. Constant tilt of 23.5° September equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness.

Global air circulation and wind patterns play major roles in determining climate patterns

LE 50-10c 60°N 30°N 0° (equator) 30°S 60°S Descending dry air absorbs moisture Descending dry air absorbs moisture 0° (equator) Ascending moist air releases moisture 30°S 60°S 30° 23.5° 0° 23.5° 30° Arid zone Tropics Arid zone

Arctic Circle 60°N Westerlies 30°N Northeast trades Doldrums 0° LE 50-10d Arctic Circle 60°N Westerlies 30°N Northeast trades Doldrums 0° (equator) Southeast trades 30°S Westerlies 60°S Antarctic Circle

Wind direction East Pacific Ocean Sierra Nevada Coast Range LE 50-12 Wind direction East Pacific Ocean Sierra Nevada Coast Range

Long-Term Climate Change One way to predict future global climate change is to study previous changes

Current range Predicted range Overlap 4.5°C warming over LE 50-14 Current range Predicted range Overlap 4.5°C warming over next century 6.5°C warming over next century

Aquatic biomes account for the largest part of the biosphere in terms of area They can contain fresh water or salt water Oceans cover about 75% of Earth’s surface and have an enormous impact on the biosphere

LE 50-15 30°N Tropic of Cancer Equator Continental shelf Tropic of Capricorn 30°S Key Lakes Rivers Estuaries Abyssal zone (below oceanic pelagic zone) Coral reefs Oceanic pelagic zone Intertidal zone

Many aquatic biomes are stratified into zones or layers defined by light penetration, temperature, and depth

Littoral zone Limnetic zone Photic zone Pelagic zone Benthic zone LE 50-16a Littoral zone Limnetic zone Photic zone Pelagic zone Benthic zone Aphotic zone Zonation in a lake

(deepest regions of ocean floor) LE 50-16b Intertidal zone Neritic zone Oceanic zone Photic zone 200 m Continental shelf Pelagic zone Benthic zone Aphotic zone 2,500–6,000 m Abyssal zone (deepest regions of ocean floor) Marine zonation

Major aquatic biomes: Lakes Wetlands Streams and rivers Estuaries Intertidal zones Oceanic pelagic biome Coral reefs Marine benthic zone

Lakes

Wetlands

Rivers & Streams

Intertidal Zones

Oceanic

Coral Reefs

Marine Benthic Zone

Annual mean temperature (°C) LE 50-18 Desert Temperate grassland Tropical forest 30 Temperate broadleaf forest 15 Annual mean temperature (°C) Coniferous forest Arctic and alpine tundra –15 100 200 300 400 Annual mean precipitation (cm)

LE 50-19 30°N Tropic of Cancer Equator Tropic of Capricorn 30°S Chaparral Key Tundra Temperate grassland High mountains Tropical forest Temperate broadleaf forest Polar ice Savanna Coniferous forest Desert

Terrestrial Biomes often named for major physical or climatic factors and for vegetation

Major terrestrial biomes: Tropical forest Desert Savanna Chaparral Temperate grassland Coniferous forest Temperate broadleaf forest Tundra

Tropical Forest

Desert

Savannah

Chaparral

Temperate Grassland

Coniferous Forest (Boreal Forest or Taiga)

Temperate Broadleaf (Deciduous) Forest

Tundra