Transcript Communities and Biomes

Communities and Biomes
Biology I
Community Ecology:
Lesson Objectives
• Recognize how unfavorable abiotic and
biotic factors affect a species.
• Describe how ranges of intolerance affect
the distribution of organisms.
• Sequences the stages of primary and
secondary succession.
Main Ideas
• All living organisms are limited by factors
in the environment.
• Ecosystems on land are grouped into
biomes primarily based on the plant
communities within them.
• Aquatic ecosystems are grouped based on
abiotic factors such as water flow, depth,
distance from shore, salinity, and latitude.
Communities
• A group of interacting populations that
occupy the same area at the same time.
• Not every community contains the same
variety
– Ex. Urban vs. rural, desert vs. artic
• Most organisms are adapted to maintain
homeostasis in their native environment.
Limiting Factors
• Environmental factors (biotic or abiotic) that
affect an organism’s population, reproduction,
distribution, or ability to survive in its
environment
• Factors that limit one population in a community
may also have an indirect effect on another
population.
• Abiotic (non-living) factors
– Sunlight, temperature, climate, water, food, soil,
space, fire
• Biotic (living) factors
– Plants and animals
Range of Tolerance
• The ability of any
organism to survive
when subjected to
abiotic or biotic
factors is called
tolerance.
• Each organism has
an upper and lower
limit to what they can
tolerate.
Ecological Succession
• Ecosystems are constantly changing.
• Succession is the orderly, natural changes
and species replacements that take place
in the communities of an ecosystem over
time.
• Occurs in stages: different species at
different stages create conditions that are
suitable for some organisms and not for
others.
• Can take decades to centuries
Primary Succession
• The colonization of new land that is
exposed by avalanches, volcanoes, or
glaciers by pioneer organisms.
• Establishment of a community in an area
of exposed rock that does not have any
topsoil.
• Lichens (combo of fungus and algae) and
some mosses are among the first
organisms to appear because they can
grow on rock.
Primary Succession
• Pioneer species are the first species in an
area.
• As pioneer species die, their decaying
organic materials, along with bits of
sediment from the rocks, make up the first
stage of soil development.
• Eventually enough soil will be present so
that trees and shrubs can grow.
• Primary succession eventually slows down
and the community becomes fairly stable.
Secondary Succession
• A stable, mature community that undergoes little
or no change in species is called a climax
community.
• Eventually, things will begin to change.
• Secondary succession refers to the sequence of
community changes that take place after a
community is disrupted by natural disasters or
human actions.
• Happens in areas that previously contained life.
• Takes less time than primary succession
Terrestrial Biomes:
Lesson Objectives
• Relate latitude and the 3 major climate
zones.
• Describe the major abiotic factors that
determine the location of a terrestrial
biome.
• Distinguish among terrestrial biomes
based on climate and biotic factors.
Effects of Latitude and Climate
• You are affected by weather and climate.
• Weather is the condition of the
atmosphere at a specific place and time.
• The distance of any point on the surface of
Earth north or south from the equator is
latitude.
• Light from the sun strikes Earth more
directly at the equator than at the poles.
Effects of Latitude and Climate
• Earth’s surface is heated differently in
different areas.
• The average weather conditions in an
area, including temperature and
precipitation, describe the area’s climate.
• Latitude has an effect on climate, as well
as elevation, landmasses, and ocean
currents.
Major Land Biomes
• Biomes are classified by:
– Their plant life
– Temperature
– Precipitation
– Animal species
Tundra
• Average precipitation: 15-25
cm/year
• Temperature range:-34°C12°C
• Plants: short grasses, shrubs
• Animals: caribou, polar bears,
birds, insects, wolves, salmon,
trout
• Location: south of the polar ice
caps in the Northern
Hemisphere, North/South pole
• Abiotic factors: soggy
summers; permafrost; cold and
dark much of the year
Taiga
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Boreal forest
Average precipitation: 30-84
cm/year
Temperature range: -54°C – 21°C
Plants: spruce and fir trees
(conifers), few deciduous trees,
small shrubs
Animals: birds, moose, beavers,
deer, wolverines, mountain lions
Location: Northern part of North
America, Europe, and Asia
Abiotic factors: summers are short
and moist; winters are long, cold,
and dry
Temperate Forest
• Average precipitation: 75-150
cm/year
• Temperature range:-30°C30°C
• Plants: oak, beech, and maple
trees, shrubs
• Animals: squirrels, rabbits,
skunks, birds, deer, foxes,
black bears
• Location: South of the boreal
forests in eastern North
America, eastern Asia,
Australia, and Europe
• Abiotic factors: well-defined
seasons, summers are hot,
winters are cold
Woodlands/Shrublands
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Average precipitation: 38-100
cm/year
Temperature range: 10°C-40°C
Plants: evergreen shrubs, corn
oak
Animals: foxes, jackrabbits, birds,
bobcats, coyotes, lizards, snakes,
butterflies
Location: surrounds the
Mediterranean Sea, western
coasts of North and South
America, South Africa, and
Australia
Abiotic factors: summers are very
hot and dry; winters are cool and
wet
Grassland
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Average precipitation: 50-89 cm/year
Temperature range: -40°C - 38°C
Plants: grasses and herbs
Animals: gazelles, bison, horses,
lions, deer, mice, coyotes, foxes,
wolves, birds, quail, snakes,
grasshoppers, spiders
• Location: North America (largest
part), South America, Asia, Africa,
and Australia
• Abiotic factors: summers are hot,
winters are cold, moderate rainfall,
fires possible
Desert
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Average precipitation: 2-26 cm/year – driest biome
Temperature range: high 20°C – 49°C, low -18°C – 10°C
Plants: cacti, Joshua trees, succulents
Animals: lizards, bobcats, birds, tortoises, rats, antelope, desert toads
Location: every continent except Europe
Abiotic factors: varying temperatures, low rainfall
Tropical Savanna
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Average precipitation: 50-130 cm/year
Temperature range: 20°C – 30°C
Plants: grasses and scattered trees
Animals: lions, hyenas, cheetahs, elephants, giraffes, zebras, birds,
insects
• Location: Africa, South America, and Australia
• Abiotic factors: summers are hot and rainy, winters are cool and dry
Tropical Rain Forest
• Average precipitatio: 200-1000
cm/year
• Temperature range: 24°C –
27°C
• Plant: broadleaf evergreens,
bamboo, sugar cane
• Animals: chimpanzees, Bengal
tigers, elephants, orangutans,
bats, toucans, sloth, cobra
snakes
• Location: Central and South
America, southern Asia,
western Africa, and
northeastern Australia
• Abiotic factors: humid all year,
hot and wet
Other Terrestrial Areas
• Mountains have abiotic conditions that
change with increasing elevation, allowing
many communities to exist.
• Polar regions border the tundra at high
latitudes and are cold all year.
Aquatic Ecosystems:
Lesson Objectives
• Identify the major abiotic factors that
determine the aquatic ecosystems.
• Recognize that freshwater ecosystems are
characterized by depth and water flow.
• Identify transitional aquatic ecosystems
and their importance.
• Distinguish the zones of marine
ecosystems.
Freshwater Ecosystems
• Major ecosystems include ponds, lakes,
streams, rivers, and wetlands
• Plants and animals are adapted to the low
salt content and unable to survive in high
salt content
• 2.5% of water on Earth is freshwater
• 68.9% is locked in glaciers, 30.8% is
groundwater, and 0.3% is lakes, ponds,
rivers, streams, and wetlands
Rivers and Streams
• Water flows in one direction
• Characteristics change during the journey
from the source to the mouth
• Rapid waters have fewer species and less
sediment and organic materials
• Plants and animals must be adapted to
withstand the constant water current
Lakes and Ponds
• An inland body of standing water
• Divided into 3 zones:
– Littoral zone – area closest to the shore,
shallow, lots of photosynthetic organisms
– Limnetic zone – open water area that is well lit
and is dominated by plankton
– Profundal zone – minimal light penetration,
much colder, lower in oxygen, limited number
of species
Transitional Aquatic
Ecosystems
• Many aquatic environments are a combination of
two or more different environments
• Wetlands: marshes, swamps, and bogs; plant
species grow in the humid, moist conditions; lots
of animal diversity
• Estuaries: among most diverse ecosystem;
formed where freshwater and saltwater meet;
many aquatic plants and detritivores
Marine Biomes
• The oceans contain the largest amount of
biomass, or living material, of any biome.
• Most of the biomass is made of extremely
small organisms.
• Separated into shallow, sunlit zones and
deeper, unlighted zones.
• The portion of marine biome that is
shallow enough for sunlight to penetrate is
called the photic zone. Ex. coastlines
Marine Biomes
• Deeper water that never receives sunlight
makes up the aphotic zone.
• The benthic zone is the area along the ocean
floor that consists of sand, silt, and dead
organisms.
• The deepest region of the ocean is the abyssal
zone.
• Twice a day, the gravitational pull of the sun and
moon causes the rise and fall of the oceans.
• The intertidal zone is the area between low tide
and high tide.
Marine Biomes
• Plankton are small organisms that live in
the waters of the photic zone.
• Zooplankton are tiny animals that feed on
plankton.
• Coral reefs are one of the most beautiful
and diverse biomes to study and are found
only in warm water about 40 meters deep.