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Discover the role of climate in shaping ecosystems, the importance of habitats, and the characteristics of various biomes on Earth. Learn about biotic and abiotic factors, ecological succession, and the diversity of aquatic ecosystems.
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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