Chapter 31
Ecosystems and Biomes
31:1 Ecosystems
A community
interacting with the
environment is an
ECOSYSTEM
Parts of an Ecosystem
What is a community?
it includes all the living things in an area. All the
LIVING THINGS are called BIOTIC FACTORS
What is an ecosystem?
it includes all the living things in an area as well
as the nonliving parts in an area. The
NONLIVING THINGS are called ABIOTIC
FACTORS.
Examples:
Some BIOTIC
FACTORS
are:
grasses, trees,
worms,
animals
Remember:
“bio-” means
life
Examples:
ABIOTIC
FACTORS:
Nonliving things
such as soil, the
sun, rain,
chemicals etc.
Ecology
The study of how
living things
interact with
each other and
with their
environment is
called
ECOLOGY.
Soil and the Nitrogen Cycle
Soil is an important part of an ecosystem.
It comes from rocks that have been broken down
Soil has many jobs:
it anchors the roots of plants
it serves as a home for many living things
it holds other nonliving things such as water, nutrients,
and gases
Nitrogen Cycle
One of the most important soil nutrients
needed by plants are called nitrates (they
contain nitrogen).
1. Plants and animals need nitrogen to
make protein (remember A, T, G, C are the
nitrogenous bases that make up what
biologically important “macromolecule”?)
Nitrogen Cycle
2. When living things
die, decomposers
break them down
(what are
examples of
decomposers?)
and release some
of the nitrogen in
their bodies. The
nitrogen is
changed into
nitrates.
Nitrogen Cycle
3. The nitrates are
left in the soil.
Plants use
them as a
source for
making
proteins.
• Then animals use
plants for food and
to create proteins
for their own
bodies. When the
animals die the
nitrogen in their
bodies is returned
to the soil.
Nitrogen Cycle
4. Some
nitrates in the
soil are
changed
back into
nitrogen gas
by bacteria.
The nitrogen
gas is
released into
the air.
Nitrogen Cycle
The atmosphere is made of up about 78%
nitrogen gas!
Water Cycle
Water is another ABIOTIC
FACTOR in an ecosystem
that is needed by all living
things.
The cells of all organisms are
mostly water. The most
human cells are about 60%
water, the human brain is
about 70% water and the
lungs are about 90% water!
Water Cycle
The path that water takes through an
ecosystem is called the WATER CYCLE
1. Water in the air falls to Earth as rain or
snow
Water Cycle
2. Some water
runs off the
land into
rivers, ponds,
lakes or
oceans.
3. Water from
rain may
soak into the
soil.
Water Cycle
4. Some of this water is
taken up by plants
through their roots.
Animals may drink
some of the water.
The rest goes
underground.
Water Cycle
5.
6.
Excess water passes
out of plants through
their leaves (this is
called
TRANSPIRATION).
Animals lose water as
waste (or sweat).
Water evaporates into
the air.
Water from lakes,
rivers and oceans also
evaporates into the air.
Oxygen-Carbon Dioxide Cycle
Air is needed in an
ecosystem.
The atmosphere is
made of Nitrogen,
Oxygen, Carbon and
other noble gases
(these gases reflect the
blue wavelength of
light, that is why the
earth appears to
have a blue “halo”)
Oxygen-Carbon Dioxide Cycle
Oxygen is given off by
producers after
photosynthesis and
is used in respiration
by plants and
animals.
Carbon Dioxide, given
off after respiration,
is used by plants for
photosynthesis.
Oxygen-Carbon Dioxide Cycle
Oxygen is also found in water for fish and
plants (yes, fish “breath” oxygen through
the water).
Carbon dioxide in the water is also used by
water plants, blue-green bacteria, and
algae for photosynthesis.
31:2 Succession
The living and nonliving parts of an ecosystem may change
over a period of time.
The changes that take place in a community as it gets older
are called SUCCESSION.
Succession
Succession happens SLOWLY! So it can be
hard to see happening.
Primary Succession
Primary Succession occurs at an area of
NEWLY EXPOSED rocks that has never
been occupied by any living things (biotic
factors)
Secondary Succession
• Secondary Succession occurs in places where a
community has been removed (like from clear
cutting a forest or plowing a field). There used
to be biotic factors present
Succession in a Land Community
In a plowed field:
weeds invade first
worms and grasshoppers arrive
beetles and ants arrive
Succession in a Land Community
As the animals die their bodies decompose
and add nutrients to the ground. Making
the soil better for other, larger animals and
plants to move in!
Succession in a Land Community
A CLIMAX COMMUNITY is the final stage of
succession in a community.
It is the final stage because it is STABLE
and can replace itself with little change
from then on.
Succession in a Land Community
It may take 150 years or more for an area to
become a climax community.
Succession in a Water Community
Succession can occur when a lake/pond
turns into a land community.
First, only microbes are present. Then,
sediments get carried in…
Succession in a Water Community
Eventually, algae come in, then larger
plants.
Over time, the pond/lake fills in with dead
plant material and larger animals move in.
Eventually, the pond/lake completely fills in
and over 100 years becomes a terrestrial
environment.
31:3 How Living Things Are
Distributed
Climate:
Light and temperature
(both abiotic factors) affect
the environment
Light from the sun is used
in photosynthesis
Producers transfer energy
to other living things
through food chains
Climate
Temperature and Light are
often related.
Soil in a forest is cool
because the trees
prevent the sunlight from
warming the ground.
Soil in an open field is warm
because the sun’s
warmth can actually
reach it to warm it.
Climate
The
temperature
of an
ecosystem
determines
what
organisms
live there
Climate
The water cycle is also
related to temperature
and light.
The amount of light can
affect the rate of
evaporation.
The warmer it is the
quicker that
evaporation occurs.
Climate
The temperature of the
air affects the type of
precipitation falling to
earth.
PRECIPITATION is
water in the air that
falls to Earth as rain
or snow.
Climate
All these factors:
light, temperature, and precipitation
Taken over many years is called the CLIMATE of an area.
The climate of an area determines what kinds of organisms live there.
Land Biomes
There are large areas on Earth that have
similar climates and climax communities.
A land area with a distinct climate and with
specific types of plants and animals is
called a BIOME.
Land Biomes
•
•
•
•
•
•
Taiga (Coniferous Forests)
Temperate Deciduous Forests
Tropical Rain Forests
Grasslands
Deserts
Tundra
Taiga Biome
• Found in the Northern
Hemisphere
– Wide range of temperatures
between winter and summer
seasons
– Winters are long and cold,
and the summers are short
and cool
– Precipitation is moderately
high throughout the year with
snow occurring during the
winter months
– Too cold for many animals to
live there year round
Taiga- continued
• Coniferous
forest often
cover
mountainsides
with tall narrow
trees packed
closely
together
Animals of the Taiga Biome
• Animals
Include:
-Large animals
such as moose,
bear, deer
-Small animals
such as
bobcats,
squirrels,
moles,
chipmunks,
insects and
birds
Taiga- Animal Adaptations
• Most animals migrate away from this
environment once it begins to get cold. Why?
• Some of those who stay will hibernate. Why?
• Others will develop a layer of insulating feathers
or fur on their bodies. Why?
• Some animals change the color of their fur from
dark in the warm months to white in the cold
months. Why?
Taiga- Plants
• Most plants found in this biome are
coniferous trees (cone baring)
-they do not lose their needles
-the needles emit a chemical that keeps
animals from eating them
-conical shape of tree and branches allow the
tree to be able to pile snow on its branches
without breaking
Temperate Deciduous Forests
• Found between the
cold polar regions
and the warm
tropical regions
• Has all 4 seasons
• Precipitation from 30
to 60 inches a year
• Most humans live in
this region
Animals of the Temperate
Deciduous Forests
• A wide variety of
animals:
-mammals, birds,
insects, reptiles,
bears, raccoons,
squirrels,
skunks, wood
mice, deer,
bobcats,
mountain lions,
timberwolves,
coyotes, elk and
bison
Temperate Deciduous ForestAnimal Adaptations
• Birds migrate away from this environment
once it begins to get cold. Why?
• Most mammals who stay will hibernate.
Why?
• Some animals will store food? Why?
Temperate Deciduous Forests
• Multiple layers:
– Tall deciduous trees create a moderately dense forest
canopy.
– The second layer of plant growth includes saplings
and species of trees that are naturally shorter in
stature.
– A third layer (or understory) would include shrubs.
– Forest herbs, such as wildflowers and berries, make
up a fourth layer.
– A fifth layer would include mosses and lichens that
grow on tree trunks.
Temperate Deciduous ForestPlant Adaptations
• In spring deciduous trees produce thin,
broad leaves to aid in photosynthesis.
• In fall leaves will change color and fall off
the tree to conserve energy for the tree.
Tropical Rainforest
• Hot, moist biome found near
Earth's equator
• The world's largest tropical
rainforests are in South
America, Africa, and Southeast
Asia.
• Tropical rainforests receive from
60 to 160 inches of
precipitation.
• Tropical rainforests contain the
greatest biodiversity in the
world. Over 15 million species
of plants and animals live within
this biome.
Animals of the Tropical
Rainforest
• Small
animals,
including
monkeys,
birds, snakes,
rodents,
frogs, and
lizards are
common in
the tropical
rainforest.
Animals of the
Tropical
Rainforest
Tropical Rainforest- Animal
Adaptations
• Some animals eat only certain kinds of
food not eaten by other animals. Why?
• Behavioral adaptations. Why?
• Camouflage. Why?
Tropical Rainforest- Plants
• Tropical rainforests get 12 hours of
sunlight daily, but only 2% of that sunlight
reaches the ground.
• Tall trees and the canopy are the majority
of plant life.
Tropical Rainforest- Plant
Adaptations
• Some plants have learned to adapt to lack of
light
• Some plants have ways of reaching the light.
• Strangler fig has seeds that will land on leaf of a
tree, eventually root reaches ground while
branches grow up toward sun and cover the
host tree, keeping the host from getting sunlight
to photosynthesize.
• Some plants grow on other plants.
Grasslands
• Lands dominated by grasses instead of
shrubs or trees
• Two Types:
– Savanna
– Temperate Grasslands
Grassland- Savanna
– Savanna- which
are in warm or
hot areas and
have a few
scattered trees
• Rainfall is
between 20 to 50
inches and
concentrated
between 6 to 8
months of the
year followed by
times of drought
Animals of the Savanna
• Animals of the
Savanna (which do
not occur in the
same Savanna)
are insects, birds,
giraffes, zebras,
buffaloes,
kangaroos, mice,
moles, gophers,
ground squirrels,
snakes, worms,
termites, beetles,
lions, leopards,
hyenas, and
elephants
Savanna- Animal Adaptations
• Most birds and large animals migrate
during the dry season. (Why?)
• Some animals get water from the food
they eat.
• Some animals go dormant. (Why?)
• During the dry season the Savanna may
catch fire, some birds specialize in eating
these “cooked” insects.
Savanna- Animal Adaptations
continued
• Animals are specialized to eat certain
parts of plants
• Camouflage
• Some animals graze
• Some animals burrow
• Birds build their nests lower- either on the
ground, in shrubs or trees. Some even
build their nests underground!
Savanna- Animal Adaptations
continued
• Some amphibians and reptiles get their
moisture from the prey they eat
• Specialized ways of getting prey
Savanna- Plants
•
•
•
•
Grasses are dominant plant life
Some can grow 6 to 9 feet tall
Trees growing alone or in small clusters
The acacia and baobab trees are common
in African savannas
Savanna- Plant Adaptations
• Some plants –
- grow quickly during the rainy season
- store nutrients and moisture in their roots
- have long tap roots to reach deep
underground water sources
- grow leaves that are thick and in fingerlike clusters
- store moisture in their trunks
Savanna- Plant Adaptations
continued
• Some plants:
- have thorns to keep animals from feeding on it
- emit a chemical in the leaves to avoid being
eaten
-emit a chemical into the air to “warn” other
plants of the same species to start emitting “bad
tasting” chemicals into their leaves (Acacia
Trees)
Savanna- Plant Adaptations
continued
• Fires in the Savanna stimulate new growth
and replenishes the soil with nutrients
– Some plants are fire resistant and will grow
from the root once the fire is gone
Grasslands- Temperate
Grasslands
• Temperate
Grasslands
– Have less rainfall than
Savanna
– Have hot summers
and cold winters
– Prairies are a type of
temperate grasslands
- Seasonal droughts
and fires are essential
for biodiversity (What
does that mean?)
Grassland- Temperate
Grassland
• The fauna (which do not all occur in the same
temperate grassland) include gazelles, zebras,
rhinoceroses, wild horses, lions, wolves, prairie
dogs, jack rabbits, deer, mice, coyotes, foxes,
skunks, badgers, blackbirds, grouses,
meadowlarks, quails, sparrows, hawks, owls,
snakes, grasshoppers, leafhoppers, and spiders.
Animals of the Temperate
Grasslands
Deserts
• Dry environment that receive
less than 15 inches of
precipitation yearly
• Large daily temperature
fluctuations
• High daytime temperatures
(possibly over 100 degrees
Fahrenheit) and low nighttime
temperatures (possibly 32
degrees Fahrenheit) make it
difficult to survive in this
environment
Desert Animals
• Reptiles, insects, birds,
and small mammals are
just a few examples of
animals that live in the
desert.
• Most large animals
have not adapted to
desert life. Their size
prevents them from
finding shelter from the
Sun's heat and they are
not able to store water
for future use.
Desert- Animal Adaptations
•
•
•
•
Staying in the shade of rocks or plants
Burrowing under ground
Nocturnal behavior
Get water from their food and not water
sources
• Presence of salt glands, absence of sweat
glands
• How do these adaptations help?
Desert Plants
• Short grasses, sagebrush, creosote
bushes, and cacti are just a few of the
plants that can be found in the desert.
Desert- Plant Adaptations
• Specialized tap roots or horizontal root
systems
• The ability to store water in the roots,
stems, leaves and fruit (succulent plants)
• Specialized leaves for reducing water loss
Arctic Tundra
• “Tundra" is a Finnish words
which means "treeless".
• Found across northern Alaska,
Canada, and Siberia
• Long cold winters and short
cool summers.
• Low precipitation (less than 10
inches per year) and dry winds
• These conditions make the
Arctic tundra a desert-like
climate
Arctic Tundra
• Permafrost ground
with an “active
layer” that melts
each summer
• The sun can
remain below the
horizon for up to 2
months causing
darkness
Arctic Tundra- Animals
• Most birds and
mammals only use
the tundra as a
summer home.
• Mammals that do
live year-round in
the tundra include
the musk ox, Arctic
wolf, and brown
bear.
Arctic Tundra- Animal
Adaptations
• Migration to warmer climates for the winter
(Why?)
• Hibernation (What is this, really?)
• Additional fat layer and/or double layers of
fur (How does this help?)
• Specialized hooves (How does this help?)
Arctic Tundra- Plants
• Some of the plants that live in the Arctic
tundra include mosses, lichens, lowgrowing shrubs, and grasses--but no
trees.
Arctic Tundra- Plant Adaptations
• Plants grow close together and close to
the ground
• Plants can grow under a layer of snow,
carry out photosynthesis in extremely cold
temperatures, and flowering plants flower
quickly in the brief summer
References:
• http://www.cotf.edu/ete/modules/msese/ea
rthsysflr/desert.html
• http://www.inchinapinch.com
• http://www.ucmp.berkeley.edu/exhibits/bio
mes/grasslands.php
• http://www.blueplanetbiomes.org/grasslan
ds.htm