Ch' 4: Ecosystems and Communities

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Ch. 4 Ecosystems and Communities

• pp. 86 - 117

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4-1 The Role of Climate

• pp. 87 - 89

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What is Climate?

• Weather
• Day-to-day condition of the Earths atmosphere at
  a particular time and place
• Climate
• Refers to the average year-after-year conditions
  of temperature and precipitation in a particular
  region

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The Greenhouse Effect

• Carbon dioxide, methane, water vapor, and a few
  other atmospheric gases trap heat energy and
  maintain Earths temperature range
• Greenhouse Effect
• Natural situation in which heat is retained by
  this layer of greenhouse gases

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The Effects of Latitude on Climate

• As a result of differences in latitude and thus
  the angle of heating, Earth has three main
  climate zones polar, temperate, and tropical

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Climate Zones
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Heat Transport in the Biosphere

• The unequal heating of the Earths surface drives
  wind and ocean currents, which transport heat
  throughout the biosphere

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4-2 What Shapes an Ecosystem

• pp. 90 - 97

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Biotic and Abiotic Factors

• Biotic factors
• Include all living organisms that inhabit and
  environment.
• Abiotic factors
• The nonliving parts of an organisms environment.
• Examples
• Air currents, soil, temperature, light and
  moisture
• These factors typically determine species
  survival.

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• Habitat
• Place where an organism lives out its life
• Organisms of different species use a variety of
  strategies to live and reproduce in their habitat.

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The Niche

• Niche
• The role and position a species has in its
  environment.
• Includes how it meets its needs for food and
  shelter, how it survives, how it reproduces, and
  how it interacts with the biotic and abiotic
  factors of its environment.

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Community Interactions

• Community interactions, such as competition,
  predation, and various forms of symbiosis, can
  powerfully affect an ecosystem.

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Competition

• Resource
• Any necessity of life, such as water, nutrients,
  light, food, or space
• This leads to competition
• Competitive exclusion principle
• States that no two species can occupy the same
  niche in the same habitat at the same time

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Predation

• Predation interaction in which one organism
  captures and feeds on another organism
• Harmful to one species, yet beneficial to
  another.
• Predator is the animal that capture, kill and
  consume the prey.
• This is referred to as the predator-prey
  relationships

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Symbiosis

• Symbiosis (living together)
• Relationships between organisms that help
  maintain survival between species.
• 3 main classes of symbiotic relationships
• Mutualism
• Commensalism
• Parasitism

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Mutualism

• Both species benefit from the relationship

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Commensalism

• One species benefits and the other is neither
  harmed nor benefited

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Parasitism

• One organism derives benefit at the expense of
  another, without actually killing the host.

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Succession Changes over Time

• Ecological Succession
• The orderly, natural changes and species
  replacements that take place in the communities
  of an ecosystem
• Eventually a climax community (a stable, mature
  community that undergoes little or no change in
  species) results.

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• Primary Succession the sequential development
  of living communities from bare rock
• Example volcano erupting
• Pioneer species the first species to populate
  the area
• Secondary Succession occurs when communities
  are disrupted
• Examples forest fire, hurricane

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4-3 Biomes

• Pg. 98 105

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Biomes

• Biome
• A complex of terrestrial communities that covers
  a large area
• Characterized by certain soil and climate
  conditions and particular plants and animals.
• Tolerance
• Ability to survive and reproduce under conditions
  that differ from their optimal conditions.

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The Major Biomes

• Includes
• Tropical rain forest, tropical dry forest,
  tropical savanna, desert, temperate grassland,
  temperate woodland and shrubland, temperate
  forest, northwestern coniferous forest, boreal
  forest, and tundra.
• Two climate factors, temperature and
  precipitation, are the major limiting factors for
  the formation of terrestrial biomes.

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• Tropical Rain Forest
• Home to more species of organisms than any other
  place on earth
• Warm temperatures (25C), wet weather (200 cm
  600 cm per year)
• Lush plant growth
• Located near the equator
• Vertical layering (ground, understory, canopy)

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• Tropical Rain Forest (cont.)
• Plants hardwoods (mahogany), orchids, moss and
  ferns
• Animals monkeys, birds, bats, chameleons,
  snakes, jaguar, ants, termites, and earthworms
• Soil not nutrient rich

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• Tropical Dry Forest
• Rainfall is highly season
• Trees lose their leaves during the dry season -
  deciduous
• Located just above and below the equator
• Plants deciduous trees, orchids and bromeliads,
  and aloes
• Animals tigers, elephants, rhinoceroses,
  termites, snakes and monitor lizards

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• Tropical Savanna
• Characterized by a cover of grasses
• Spotted with isolated shrubs and trees
• Compact soils and fairly frequent fires
• Plants tall perennial grasses, trees and shrubs
• Animals lions, leopards, cheetahs, hyenas,
  jackals, elephants, giraffes, zebras, eagles,
  ostriches, and termites

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• Desert
• Driest biome less than 25cm of precipitation
  annually
• Plants cacti and small shrubs
• Animals desert tortoises, snakes, coyotes,
  hawks, owls, roadrunners, lizards, and scorpions

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• Grassland Breadbaskets of the World
• Large community covered with grasses and similar
  small plants
• Experience a dry season
• Contains fewer than 10 15 trees per hectare
• Animals grazing animals (bison), coyotes,
  wolves, prairie dogs, insects, birds and reptiles
• Plants any type of grasses (oats, rye, wheat)

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• Temperate Woodland and Shrubland
• Semiarid climate
• Characterized by open woodlands, large areas of
  grasses and wildflowers with oak trees
• Plants evergreen shrubs, herbs
• Animals coyotes, foxes, bobcats, mountain lions,
  blacktailed deer, rabbits, quails, lizards and
  snakes

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• Temperate Forest
• Between 70 150 cm of precipitation annually
• Top layer of soil is very rich
• Plants Dominated by broad leaved deciduous
  hardwoods, conifers, flowering shrubs, ferns
• Animals squirrels, deer, rabbits, mice, black
  bears, bluejays, and salamanders
• This is where we live.

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• Northwestern Coniferous Forest
• Moist air from the Pacific Ocean provides
  abundant rainfall
• Located along the northern California coast
• Plants Douglas fir, Sitka spruce, western
  hemlock, redwoods
• Animals bears, elk and deer, beavers, owls,
  bobcats and weasels

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cold bu
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• Boreal Forest (Taiga)
• Along the northern edge of the temperate zone
• Winters are bitterly cold but summers are mild
• Acidic nutrient-poor soil
• Plants spruce, fir, berry-bearing shrubs
• Animals lynxes, timber wolves, moose, beavers,
  migratory birds

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• Tundra
• Treeless land with long summer days and short
  periods of winter sunlight
• Temperatures never rise above freezing for long
• Permafrost permanently frozen ground under the
  topsoil
• Thin topsoil can only support shallow-rooted
  grasses and other small plants lacks nutrients

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• Tundra
• Process of decay is slow because of cold
  temperatures
• Short growing season
• Plants grasses, dwarf shrubs, cushion plants
• Animals migratory waterfowl, shore birds, musk
  ox, artic foxes, caribou and lemming

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4-4 Aquatic Ecosystems

• Pg. 106 - 112

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Aquatic Ecosystems

• Aquatic ecosystems are determined primarily by
  the depth, flow, temperature, and chemistry of
  the overlying water.

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Freshwater Ecosystems

• Two main types
• Flowing-water ecosystems
• Rivers, stream, creeks and brooks
• Originate in mountains or from an underground
  water source
• Upstream insect larvae, catfish, trout
• Downstream turtles, beavers and river otters

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• Two main types (cont.)
• Standing-water ecosystems
• Lakes and ponds
• Water is usually circulating within them
• Organisms plankton ( tiny, free-floating
  organisms)
• Phytoplankton algae
• Zooplankton animal-like that feed on
  phytoplankton

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• Freshwater Wetlands
• Wetland an ecosystem in which water either
  covers the soil or is present at or near the
  surface of the soil for part of the year
• Water may be flowing or standing and can be
  freshwater, salt water or brackish
• 3 main types bogs, marshes and swamps

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Estuaries

• Estuaries
• wetlands formed where rives meet the sea
• Affected by the high and low tide
• Producers plants, algae and bacteria
• Detritus organic matter that provides food for
  clams, worms and sponges
• Serve as spawning grounds for shrimp and crabs

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• Salt marshes
• temperate-zone estuaries dominated by
  salt-tolerant grasses
• Located along eastern North America from Maine to
  Georgia
• Mangrove swamps
• Coastal wetlands along the tropical regions
  including Florida (Everglades) and Hawaii
• Plants salt-tolerant trees and seagrasses
• Serve as nurseries for fish and shellfish

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Marine Ecosystems

• Photic zone shallow enough for sunlight
• Photosynthesis occurs here through algae and
  other producers
• Aphotic zone deeper water that never receives
  sunlight
• Chemosynthetic autotrophs live here

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Marine Ecosystems (continued)

• Marine biologists divide the oceans into zones
  based on the depth and distance from the shore.
• Intertidal zone
• Coastal ocean
• Open ocean

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Marine Ecosystems (continued)

• Intertidal Zone
• Organisms that live here are exposed to regular
  and extreme changes in their surroundings
• Submerged twice a day and exposed to air,
  sunlight, and temperature changes rest of the
  day.
• Zonation- prominent horizontal banding of
  organisms that live in a particular habitat

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Marine Ecosystems (continued)

• Coastal Ocean
• Extends from the low-tide mark to the outer edge
  of the continental shelf (relatively shallow
  border that surrounds the continents)
• Located in the photic zone and is rich in
  plankton and other organisms
• Kelp forests named for the giant brown algae
  that can grow up to 50 cm a day
• Most productive coastal ocean communities

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Marine Ecosystems (continued)

• Coral Reefs
• Named for the coral animals whose hard, calcium
  carbonate skeletons make up their primary
  structure
• Most diverse and productive environment
• Thrive only in brightly lit areas within 40
  meters of the surface

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Marine Ecosystems (continued)

• Open Ocean
• Begins at the edge of the continental shelf and
  extends outward
• Largest of the marine zone (covers more than 90
  of the surface of the worlds oceans)
• Depth is from 500 m to 11,000 m
• Organisms exposed to high pressure, frigid
  temperatures, and total darkness

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Marine Ecosystems (continued)

• Open Ocean (continued)
• Has very low levels of nutrients and supports
  only the smallest producers
• Most of the Earths photosynthetic production
  occurs in the part of the open ocean in the
  photic zone (due to the enormous area)
• Common organisms squid, octopus, whale,
  dolphins, swordfish, variety of fish

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Marine Ecosystems (continued)

• Benthic Zone
• Extends from horizontally along the ocean floor
  from the coastal ocean through the open ocean
• Benthos organisms (such as sea stars, anemones,
  and marine worms) that live on the oceans floor