Download ecosystems and biomes

Ecosystems and Biomes
Chapter 2: Section 1
“Energy Flow in Ecosystems”
Objectives
• After completing the lesson, students will
be able to:
– Describe the energy roles of organisms in an
ecosystem;
– Explain food chains and food webs;
– Describe how much energy is available at each
level of an energy pyramid.
Energy Roles
• An organism’s energy role is determined by
how it obtains energy and how it interacts
with the other living things in its ecosystem.
• An organism’s energy role in an ecosystem
may be that of a producer, consumer, or
decomposer.
Producers
• Energy first enters most
ecosystems as sunlight.
• Producer—An organism
that can make its own
food.
• Producers are the source
of all the food in an
ecosystem.
• Examples: grass and oak
trees.
Consumers
• Consumer—An organism
that obtains energy by
feeding on other
organisms.
– Herbivores—Consumers
that eat only plants
– Carnivores—Consumers
that eat only animals
– Omnivore—Eats both
plants and animals
– Scavenger—A carnivore
that feeds on the bodies of
dead organisms.
Decomposers
• Decomposers—
Organisms that break
down wastes and dead
organisms and return
the raw materials to
the environment.
• Two major groups of
decomposers are
bacteria and fungi
Food Chains and Food Webs
• Food chain—A series of events in which
one organism eats another and obtains
energy.
– 1st—Producer
– 2nd—First-Level Consumer
– 3rd—Second-Level Consumer
Food Web—Consists of many overlapping food
chains in an ecosystem.
Energy Pyramid
• When an organism in an ecosystem eats, it
obtains energy. The organism uses some of
its energy to move, grow, and reproduce,
and carry out other life activities.
• This means that only some of the energy
will be available to the next organism in the
food web.
Energy Pyramid
• Energy Pyramid—Shows the amount of energy that
moves from one feeding level to another in a food web.
• The most energy is available at the producer level. At each
level in the pyramid, there is less available energy than at
the level below.
• An energy pyramid gets its name from the shape of the
diagram—wider at the base and narrower at the top,
resembling a pyramid.
• In general, only about 10% of the energy at one level of a
food web is transferred to the next, higher, level. The other
90% is used for the organism’s life processes or is lost as
heat to the environment.
Energy Pyramid
• Since 90% of the energy is lost at each step, there
is not enough energy to support many feeding
levels.
• Organisms at higher feeding levels of an energy
pyramid do not necessarily require less energy to
live than organisms at lower levels. Since so
much energy is lost at each level, the amount of
energy in the producer level limits the number of
consumers the ecosystem can support. As a result,
there usually are few organisms at the highest
level in a food web.
Ecosystems and Biomes
Chapter 2: Section 2
“Cycles of Matter”
Objectives
• After completing the lesson, students will
be able to . . .
– Describe the three major processes that make
up the water cycle;
– Describe the carbon-oxygen cycle and the
nitrogen cycle
Recycling Matter
• The supply for matter is limited, which
means there isn’t much of it.
• If matter could not be recycled, ecosystems
would quickly run out of the raw materials
necessary for life.
• Energy, on the other hand, is not recycled
Recycling Matter
• Matter cycles through an ecosystem over
and over.
• Matter in an ecosystem includes water,
oxygen, carbon, nitrogen, and many other
substances.
The Water Cycle
• Water is necessary for life as we know it.
• Water cycle—The continuous process by
which water moves from Earth’s surface to
the atmosphere and back.
• The process of evaporation, condensation,
and precipitation make up the water cycle.
Evaporation
• Evaporation—The process by which molecules
of liquid water absorb energy and change to the
gas state.
• Liquid water evaporates from Earth’s surface and
forms water vapor, a gas, in the atmosphere.
• Most water evaporates from oceans and lakes.
• Water is also produced through living things;
plants release water vapors from their leaves,
people release water through waste and water
vapor when they exhale.
Condensation
• Condensation—The
process by which a gas
changes to a liquid.
• As water vapor rises
higher in the atmosphere,
it cools down. When it
cools to a certain
temperature the vapor
turns back into tiny drops
of liquid water.
Precipitation
• Precipitation—Rain,
snow, sleet, or hail.
• As more water
condenses, the drops
of water in the clouds
grow larger and
heavier, eventually
falling back down to
Earth.
The Carbon and Oxygen Cycles
• Carbon is the building block for the matter that
makes up the bodies of living things.
• Producers take in carbon dioxide from the
atmosphere during photosynthesis.
• In this process, the producers use carbon from the
carbon dioxide to produce other carbon-containing
molecules.
• At the same time, oxygen is also cycling through
the ecosystem.
The Nitrogen Cycle
• Nitrogen gas is called “free” nitrogen,
meaning it is not combined with other kinds
of atoms.
• Most organisms can use nitrogen only once
it has been “fixed,” or combined with other
elements to form nitrogen-containing
compounds.
The Nitrogen Cycle
• Nitrogen Fixation:
– Nitrogen fixation—The process of changing
free nitrogen gas into a usable form of nitrogen.
– Nodules—Bumps on the roots of certain plants
that house nitrogen-fixing bacteria.
– These plants, known as legumes, include
clover, beans, peas, alfalfa, and peanuts.
The Nitrogen Cycle
• Return of Nitrogen to the Environment:
– Once the nitrogen has been fixed into chemical
compounds, it can be used by organisms to build
proteins and other complex substances.
– Decomposers break down complex compounds in dead
organisms and returns simple nitrogen compounds back
into the soil.
– Eventually, bacteria breaks down the nitrogen
compounds completely and release free nitrogen back
into the air. Then the cycle starts again.
Ecosystems and Biomes
Chapter 2: Section 3
“Biogeography”
Objectives
• After completing the lesson, students will
be able to . . .
– Describe some different means that disperse
organisms;
– Identify the factors that limit the distribution of
a species
Biogeography
• Biogeography—The
study of where
organisms live.
• Bio– “life”
• Geo– “Earth”
• Graph– “Description”
Continental Drift
• Continental Drift—The very slow motion
of the continents.
• All of today’s continents were once together
in a large landmass known as Pangaea.
Slowly, the continents started to drift apart
to where they are presently located.
• The movement of the continents has had a
great impact on the distribution of species.
Means of Dispersal
• Dispersal—The movement of organisms
from one place to another.
• Dispersal can be caused by wind, water, or
living things, including humans.
Wind and Water
• Wind provides a means of
dispersal fro seeds, the
spores of fungi, tiny
spiders, and many other
small, light organisms.
• Water transports objects
that float in which
organisms, such as insects,
get a “free ride” to another
location.
Other Living Things
• Example:
– A goldfinch may eat seeds in one area and
deposit them elsewhere in its waste.
– A duck may carry algae or fish eggs on its feet
from pond to pond.
– Dogs and cats can carry sticky plant burs that
attach to their fur.
– Humans intentionally/unintentionally transports
organisms from one region to another.
Other Living Things
• Native Species—Species that have
naturally evolved in an area.
• Exotic Species—Species that has been
carried into a new location by people
Limits to Dispersal
• Three factors that limit dispersal of a
species are physical barriers, competition,
and climate
Limits to Dispersal
• Physical Barriers
– Water
– Mountains
– Deserts
• Competition
– When an organism enters a
new area, they have to
compete for resources.
Organisms have to have a
unique niche in order to
survive.
• Climate—The typical
weather in an area over a
long period of time.
• The different types of
climate can limit the
number of organisms that
can inhabit an area.
Ecosystems and Biomes
Chapter 2: Section 4
“Earth’s Biomes”
Objectives
• After completing the lesson, students will
be able to . . .
– List and describe Earth’s major land biomes;
– List and describe Earth’s major freshwater and
ocean biomes
Biomes
• Biome—A group of ecosystems with
similar climates and organisms.
• It is mostly the climate conditions—
temperature and rainfall—in an area that
determine its biome.
Rain Forest Biomes
• Climate of Rain Forests = warm and humid
• Tropical Rain Forests
–
–
–
–
Found close to the equator
Receive lots of rain
Sunlight is fairly constant
The abundant plant life provides many habitats for
animals
– Contain more species of plant an animals than all the
other land biomes combined.
Rain Forest Biomes
• Canopy—A leafy roof formed by tall trees.
• Understory—A layer of shorter plants that
grow in the shade of a forest canopy.
Canopies and Understories
Rain Forest Biomes
• Climate of Rain Forests = warm and humid
• Temperate Rain Forests
– Too far north and too cool to be a tropical rain
forest
– The term temperate means moderate
temperature
Desert Biome
• Desert—An area that
receives less than 25
centimeters of rain per
year.
• The organisms that live in
the desert are adapted to
the lack of rain and to the
extreme temperatures.
• Many desert animals are
most active at night when
the temperatures are
cooler.
Grassland Biome
• Grassland—An area that
receives between 25-75
centimeters of rain each
year, and is typically
populated by grasses and
other non-woody plants.
• Savannas—Grasslands
that are located closer to
the equator than prairies.
• Grasslands are home to
many of the largest
animals on Earth.
Deciduous Forest Biomes
• Deciduous trees—Trees
that shed their leaves and
grow new ones each year.
– Example: Oaks and Maple
trees
– Receive enough rain to
support the growth of trees
and other plants
– The growing season usually
lasts five to six months.
– The variety of plants in the
forest creates many
different habitats
Deciduous Forest Biomes
• If you were to return to this biome during
the winter, you would not see much of the
wildlife that you are able to observe during
the warm temperatures.
• Hibernation—A low-energy state similar to
sleep.
– During hibernation an animal relies on fat it has
stored in its body.
Boreal Forest Biomes
• Coniferous trees—
Trees that produce
their seeds in cones
and have leaves
shaped like needles.
• Sometimes referred by
its Russian name
“Taiga”
• Winters are very cold
Boreal Forest Biomes
• Yearly snowfall can reach heights well over
your head
• A limited number of trees have adapted to
the cold climate
• Prevention of water loss is a necessary
adaptation for trees
• Many of the animals found here eat the
seeds produced by the conifers
Tundra Biome
• Tundra—An
extremely cold, dry,
land biome.
• Permafrost—The
frozen soil found in
the Tundra
Tundra Biome
• Plants on the tundra include mosses,
grasses, shrubs, and dwarf forms of a few
trees, such as willows.
• Most of the plant growth takes place during
the long summer days when many hours of
sunshine combine with the warmest
temperature.
Mountains and Ice
• The climate conditions
of a mountain change
from its base to its
summit.
• As a result, different
species of plants and
other organisms
inhabit different parts
of the mountain
Freshwater Biomes
• Water biomes include both freshwater and
saltwater (also called marine) biomes
• All of these are affected by the same abiotic
factors: Temperature, sunlight, oxygen, and
salt content
• Because water absorbs sunlight, there is
only enough light for photosynthesis near
the surface or in shallow water.
Ponds and Lakes
• Ponds and lakes are
bodies of standing, or
still, fresh water.
• Lakes are generally
larger and deeper than
ponds.
• Ponds are often
shallow enough that
sunlight can reach the
bottom
Streams and Rivers
• Animals that live in this
part must be adapted to
the strong current
• Few plants and algae can
grow in this fast-moving
water
• Different organisms are
adapted to live in this
lower part of the river.
Estuaries
• Estuary—An area found
where the fresh water of a
river meets the salt water
of the ocean.
• The shallow, sunlit water,
plus a large supply of
nutrients carried in by the
river, makes an estuary a
very rich habitat for living
things
• Major producers: plants
and algae
Intertidal Zone
• Intertidal Zone—The
part of the shore between
the highest high-tide line
and the lowest low-tide
line.
• Organisms here must be
able to withstand the
pounding action of waves,
sudden changes in
temperature, and being
both covered with water
and then exposed to the
air.
Neritic Zone
• Neritic Zone—The
region of shallow
ocean water over the
continental shelf.
• Many large schools of
fish feed on the algae,
and the formation of
coral reefs may occur
in the Neritic Zone.
Ecosystems and Biomes
Chapter 2: Section 5
“Succession”
Objectives
• After completing the lesson, students will
be able to . . .
– Describe the differences between primary and
secondary succession
Succession
• Succession—The series of predictable
changes that occur in a community over
time.
• Examples: Fires, floods, volcanoes,
hurricanes, and other natural disasters.
Primary Succession
• Primary succession—A series of changes that
occur in an area where no ecosystem previously
existed.
• Such an area might be a new island formed by the
eruption of an undersea volcano, or an area of rock
uncovered by a melting sheet of ice.
• Pioneer Species—The first species to populate an
area.
Secondary Succession
• Secondary Succession—A series of changes that
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•
•
•
occur after a disturbance in an existing ecosystem.
Natural disturbances that have this effect include
fires, hurricanes, and tornadoes.
Human activities, such as farming, logging, or
mining, may also disturb an ecosystem.
Unlike primary succession, secondary succession
occurs in a place where an ecosystem has
previously existed.
Secondary succession occurs somewhat more
rapidly than primary succession.