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Chapter 4. Ecosystems and Communities. 4-1 The Role of Climate. Organisms vary in their “ideal” conditions Also vary in tolerance to change Many of these conditions or changes refer to climate/weather. Weather vs. Climate. Weather : conditions at a particular time and place
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Chapter 4 Ecosystems and Communities
4-1 The Role of Climate • Organisms vary in their “ideal” conditions • Also vary in tolerance to change • Many of these conditions or changes refer to climate/weather
Weather vs. Climate • Weather: conditions at a particular time and place • Climate: average conditions in a particular region • Effected by: atmosphere, latitude, winds, currents, precipitation, etc.
GreenhouseEffect • Natural situation in which heat is retained by layer of gases (CO2, methane) • Atmosphere acts as a natural insulator • Would be 30 degrees cooler without
Latitude • Polar zones- always cold • Temperate zones- varies hot/cold • Tropical zones- always hot • Heat transfer by: • Water- currents • Air- hot air rises/cool air falls (winds)
4-2 What shapesan ecosystem? • Habitat:area where an organism lives • Made up of: • Biotic factors: biological influences • Competitors, predators, prey • Abiotic factors: nonliving influences • Climate, nutrient availability
Niche • All factors that influence an ecosystem and how the organism uses them • The “role” of an organism • Competition Exclusion Principle: no 2 organisms can have the same niche • Ex: warbler bird
Community Interactions • Competition: attempt to use same resource at same place/same time • Predation: one organisms feeds on another • Symbiosis: two species in a relationship together
Types of Symbiosis • Mutualism: both benefit • Ex: flowers and insects • Commensalism: 1 benefits, other not effected • Ex: barnacle and whale • Parasitism: 1 benefits, other is harmed • Lives on/inside “host”- does NOT kill • Ex: tapeworm, ticks
Ecological Succession • Gradual change after a disturbance (natural or man-made) • Primary: succession when there is no soil • Pioneer species: first to populate an area • Secondary: succession when soil is still there
4-3 Biomes • Biome: group of communities covering a large area • Characterized by: • soil, • climate • specific plants and animals
The Biomes: • 1. Tropical rain forest (ex: Brazil) • Hot and wet • Ferns, monkeys, toucans • 2. Tropical dry forest (ex: India) • Warm with wet and dry seasons • Deciduous trees, tigers, elephants
3. Tropical savanna (ex: Kenya) • Warm with seasonal rain, lightning fires • Grasses, shrubs, lions, hyenas • 4. Desert (ex: Arizona) • Low precipitation (dry), variable temps. • Cactus, snakes, lizard
5. Temperate grassland (ex: Texas) • Hot/cold seasons, average precipitation, fertile soil • Grasses, bison, grasshoppers • 6. Temperate woodland (ex: Los Angeles) • Hot, dry summerand cool. wet winter • Evergreens, coyote, mountain lion
7. Temperate forest (ex: Philadelphia) • Moderate winter, warm summer, year round rain • Moss, coniferous trees, deer, squirrel • 8. Northwestern coniferous forest (ex: Seattle) • Mild temps., cool, dry summer- otherwise wet • Conifer trees (redwood), bears
9. Boreal forest/ Taiga (ex: northern Europe) • Long, cold winter, short, dry summer • Fir trees, lynx, moose • 10. Tundra (ex: Alaska) • Permafrost- layer of permanent frozen soil • Short grass, caribou, owl
Other land areas: • Mountain ranges (ex: WA state) • Factors change with elevation • Polar ice caps (ex: Antarctica) • Border tundra • Polar bears, insects
4-4 Aquatic Ecosystems • Grouped by abiotic factors • Depth (amount of light) • Nutrients available • O2 available
Freshwater (only 3%) • Flowing water- organisms adapt to the flow • Standing water- flow in and circulation of nutrients, O2 and heat • Freshwater wetlands- bogs, marshes and swamps- very diverse!
Estuaries • Wetlands where rivers meet the sea • Detritus = lots of biomass • Ideal for feeding, breeding, nesting, spawning • Ex: salt marshes and mangrove swamps • Salt tolerant
Marine Ecosystems • Photic zone: well-lit upper layer • Aphotic zone: dark (200m and deeper)
Marine Zones • 1. intertidal • Extreme changes with tides • Hot and dry to covered in water • Waves and currents • 2. coastal ocean • Low tide mark to continental shelf • Photic areas = phytoplankton • Ex: kelp forests and coral reefs
3. open ocean • Continental shelf outwards • Low nutrients = low productivity • 4. benthic- along ocean floor • Benthos: organisms that live here • Food depends on depth: photic producers,, detritus, chemosynthesis