Transcript Communities and Biomes

Communities and
Biomes
Communities
► In
communities there are various
combinations of abiotic and biotic factors
that result in conditions that are suitable for
supporting certain forms of life but not
others.
► Limiting Factors- are any biotic or abiotic
factor that restricts the existence, numbers,
reproduction, or distribution of organisms.
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Ranges of Tolerance
► Tolerance-
The ability of an organism to
withstand fluctuations in biotic and abiotic
environmental factors.
 The limits of an organism’s tolerance are
reached when the organism receives too much
or too little of some environmental factor.
►Populations
respond by becoming smaller as
conditions move toward either extreme.
Succession
► Primary
Succession- The colonization of barren
land by communities. It takes place on land
where there are no living organisms. (Ex. Creating
a community after a volcano erupts)
 Climax Community- A stable mature community that
undergoes little or no change. It may last for hundreds
of years.
► Stability
doesn't mean that it doesn't change at all. For
example the numbers in a species might go up or down.
► Secondary
Succession- is the sequence
of changes that takes place after an existing
community is severely disrupted in some
way. (ex. The rebuilding of a community
after a forest fire)
 It takes place in areas that previously contained
life and on land that still contains soil.
►Because
soil already exist it may take less time for a
secondary succession to reach a climax community.
Biomes
► Biome-
a large group of ecosystems
that share the same type of climax
community.
 These communities are adapted to the same
types of conditions in their biome.
Aquatic Biomes
► Marine
ocean.
Biome- biome that is located in the
 Photic zone- is the portion of the marine
biome that is shallow enough for sunlight to
penetrate. They are usually located around the
coast lines. (Ex. Bays, rocky shores, sandy
beaches, estuaries, and coral reefs)
 Aphotic Zone- Is the deeper water that never
receives sunlight and it is the least explored
area of the ocean.
Estuaries – Mixed Waters
► Estuary-
is a coastal body of water,
partially surrounded by land, in which
freshwater and salt water mix.
 The salinity, or the amount of salt, in an estuary
ranges between that of sea water and
freshwater and depends on how much
freshwater the river brings into the estuary.
►Plankton-
are small organisms that drift and float in
the waters of the photic zone. They are important
because they form the base of all aquatic food
chains.
Freshwater Biomes
► The
shallow water around the shore line
supports most of the life in freshwater.
Most of the plants such as cattails grow
here and creates a home for most of the
aquatic life such as tadpoles, insects, and
turtles.
 Any dead organisms drift to the bottom of the
water and bacteria use oxygen to bread them
down and recycle the nutrients.
Terrestrial Biomes
► Tundra-
located directly south of the north pole
and is a treeless land with long summer days and
short periods of winter sunlight.
 It never rises above freezing for long and only the top
most layer of soil thaws during the summer.
► Permafrost-
lies directly underneath the top layer of soil and is
permanently frozen.
► The types of organisms that can be supported are few due to a
lack of nutrients.
► The plants are limited and consist of grasses and dwarf shrubs.
Taiga
► Located
just south of the tundra and circles the
north pole.
► It is almost a continuous belt of coniferous trees.
Common trees are spruce, fir, and hemlock.
► This biome is warmer and wetter than the tundra
but still have long severe winter and short mild
summers.
► It stretches across much of Canada, Northern
Europe, and Asia.
► Some animals include the caribou, lynx, hare,
squirrels, deer, moose, and elk.
Desert
► It
is the driest biome and has almost nonexistent
plant life.
► The plants that do live in the desert have many
adaptations to support life in such dry conditions.
Such as photosynthetic stems, thick waxy coats,
and leaves that curl up which are all ways to
conserve water.
► Animals in the desert also have to have
adaptations to survive in this dry biome.
► The kangaroo rat is a desert herbivore that does
not have to drink water but gets the water that it
needs from its food.
Grasslands
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A large community that is covered with rich soil, grasses,
and similar plants.
Grasslands occur in climates that experience a dry season
where insufficient water exist to support forest.
Grassroots survive throughout the winter and enlarge
every year to form a continuous underground mat of roots
called sod.
Some grasslands are ideal for growing grains and each
type of grain is a different species so the grasslands are
known as the breadbasket of the world.
Many animals graze in the grasslands and some examples
are bison, deer, and elk. Other animals are rabbits and
prairie dogs.
Temperate Forest
► Temperate
forest or deciduous forest are
dominated by broad leaved hardwood trees
that lose their foliage annually. Examples
are maple, oak, birch, elm, and ash.
► The soil is usually a top layer that is rich soil
and a deeper layer of clay.
► Some of the animals are squirrels, mice,
rabbits, deer, and bears. There are also
many species of birds.
Rain Forest
► It
is home to more species that any other biome.
► There are two types: Temperate and tropical.
 Both have extensive amounts of moisture supplied by
rainfall.
► Most
of the nutrients in tropical rain forest are tied up in the
living materials. There are very few nutrients held in the soil
and are quickly recycled through complex food webs. Hot humid
climate enables ants, termite, and other decomposes to break
down dead plants and animals rapidly.
► Tropical
rain forest support a wide variety of plants
and animals.
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