ch. 3: communities and biomes. what is climate? weather day-to-day condition of the earth’s...
TRANSCRIPT
Ch. 3: Communities and Biomes
What is Climate?
Weather Day-to-day condition of the Earth’s
atmosphere at a particular time and place Climate
Refers to the average year-after-year conditions of temperature and precipitation in a particular region
The Greenhouse Effect
Carbon dioxide, methane, water vapor, and a few other atmospheric gases trap heat energy and maintain Earth’s temperature range
Greenhouse Effect Natural situation in which heat is retained
by this layer of greenhouse gases
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
Climate Zones
Heat Transport in the Biosphere
The unequal heating of the Earth’s surface drives wind and ocean currents, which transport heat throughout the biosphere
Biotic and Abiotic Factors
Biotic factors Include all living organisms that inhabit and
environment. Abiotic factors
The nonliving parts of an organism’s environment.
Examples: Air currents, soil, temperature, light and
moisture These factors typically determine species
survival.
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.
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
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.
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.
Tropical Rain Forest Home to more species of organisms than
any other place on earth Warm temperatures (25°C), wet weather
(200 cm – 600 cm per year) Lush plant growth Located near the equator Vertical layering (ground, understory, &
canopy)
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
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
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
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
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)
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
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.
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
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
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
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
Aquatic Ecosystems
Aquatic ecosystems are determined primarily by the depth, flow, temperature, and chemistry of the overlying water.
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
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
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
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
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
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
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
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
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
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
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 world’s oceans)
Depth is from 500 m to 11,000 m Organisms exposed to high pressure,
frigid temperatures, and total darkness
Marine Ecosystems (continued)
Open Ocean (continued) Has very low levels of nutrients and
supports only the smallest producers Most of the Earth’s 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
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 ocean’s floor