Transcript 8th Grade Chapter 18 Interactions Within Ecosystems

Chapter Introduction
Lesson 1
Ecosystems
Lesson 2
Energy and
Matter
Lesson 3
Humans and
Ecosystems
Chapter Wrap-Up
How do living things
interact with each other
and the environment?
What do you think?
Before you begin, decide if you agree or
disagree with each of these statements.
As you view this presentation, see if you
change your mind about any of the
statements.
Do you agree or disagree?
1. In symbiosis, two species cooperate in
a way that benefits both species.
2. Overpopulation can be damaging to an
ecosystem.
3. Sunlight provides the energy at the
base of all food chains on Earth.
4. A detritivore is a type of carnivore.
Do you agree or disagree?
5. Human actions can have unintended
effects on the environment.
6. The only job of the U.S. Environmental
Protection Agency is to enforce
environmental laws.
Ecosystems
• How can you describe an ecosystem?
• In what ways do living organisms
interact?
• How do population changes affect
ecosystems?
Ecosystems
• habitat
• predation
• population
• symbiosis
• community
• carrying capacity
• niche
Abiotic and Biotic Factors
• Ecosystems contain all the nonliving
and living parts of the environment in a
given area.
• The nonliving parts—called abiotic
factors—include sunlight, water, soil,
and air.
• The living or once-living parts of an
ecosystem—called biotic factors—
include living organisms and the
decayed remains of dead organisms.
Abiotic and Biotic Factors (cont.)
How can you describe an
ecosystem?
Habitats
A habitat is the area
within an ecosystem
that provides the biotic
and abiotic factors an
organism needs to
survive and reproduce.
Populations and Communities
• A population is the number of individual
organisms of the same species that live
in an ecosystem at the same time.
• All the populations living in an area at the
same time form a community.
Populations and Communities (cont.)
community
from Latin communitatem, means
“fellowship”
Interactions of Living Things
• More than one population can live in the
same habitat because each species has
a different way of using the resources.
• A niche is the way a species interacts
with abiotic and biotic factors to obtain
food, find shelter, and fulfill other needs.
Giraffes, kudus, and steenboks have
different niches. Each has a different way
of using the resources.
Interactions of Living Things (cont.)
• A predator is an organism that hunts and
kills other organisms for food.
• Prey is an organism caught and eaten by
a predator.
• Predation is the act of one organism,
the predator, feeding on another
organism, its prey.
Interactions of Living Things (cont.)
• Symbiosis is a close, long-term
relationship between two species that
usually involves an exchange of food or
energy.
• The three types of symbiosis are
mutualism, commensalism, and
parasitism.
Interactions of Living Things (cont.)
• In mutualism, both species benefit from
the relationship.
• In commensalism, one species benefits
from the relationship and the other
species is neither harmed nor benefited.
• In parasitism, one species (the parasite)
benefits and the other (the host) is
harmed.
Interactions of Living Things (cont.)
What is one way that living
things interact?
Interactions of Living Things (cont.)
• Organisms that share the same habitat
often compete for resources.
• Competition describes interactions
between two or more organisms that
need the same resource at the same
time.
Population Changes
• Populations increase when offspring are
produced or when new individuals move
into a community.
• Populations decrease when individuals
die or move away.
Population Changes (cont.)
• Changes in the abiotic factors of an
ecosystem affect population size.
• If a drought reduces plant growth, less
food is available for plant eaters, which
can lead to a decrease in plant-eater
populations.
Population Changes (cont.)
• Interactions between organisms also
affect population size.
• For example, the
wolf population can
keep increasing
until there are no
longer enough
moose to support it.
Population Changes (cont.)
• Population density is the size of a
population compared to the amount of
space available.
• A high population density can increase
competition and make it easier for
disease to be transmitted from one
individual to another.
Population Changes (cont.)
• There is a limit to resources an
ecosystem can provide.
• Carrying capacity is the largest number
of individuals of one species that an
ecosystem can support over time.
• If a population exceeds its carrying
capacity the area becomes overpopulated.
Population Changes (cont.)
• If all the members of a population die or
move away from an area, that population
becomes extinct.
• If all populations of a species disappear
from Earth, the entire species becomes
extinct.
Population Changes (cont.)
How do population changes
affect ecosystems?
• Ecosystems are all the living and
nonliving things in a given area.
• Species in the
same habitat have
different niches.
• Populations can
increase and
decrease.
Which term refers to an organism
that hunts and kills other
organisms for food?
A. niche
B. parasite
C. predator
D. prey
Which term refers to interactions
between organisms that need the
same resource at the same time?
A. competition
B. mutualism
C. predation
D. symbiosis
Which is the largest number of
individuals of one species that an
ecosystem can support over time?
A. carrying capacity
B. community
C. population density
D. symbiosis
Do you agree or disagree?
1. In symbiosis, two species cooperate in
a way that benefits both species.
2. Overpopulation can be damaging to an
ecosystem.
Energy and Matter
• How does energy move through an
ecosystem?
• How does matter move through an
ecosystem?
Energy and Matter
• producer
• consumer
• detritivore
• food web
• energy pyramid
Food Energy
• Producers are organisms that use an
outside energy source, such as the Sun,
and produce their own food.
• Most producers—green plants, algae,
and some kinds of bacteria—make
energy-rich compounds through
photosynthesis.
Food Energy (cont.)
Some producers make energy-rich
compounds through chemosynthesis, a
process in which a chemical such as
hydrogen sulfide or methane is used to
produce glucose.
Consumers
• Organisms that cannot make their own
food are consumers.
• Consumers obtain energy and nutrients
by consuming other organisms or
compounds produced by other
organisms.
Consumers (cont.)
consumer
Science Use an organism that
cannot make its own food
Common Use a person who uses
economic goods
Consumers (cont.)
• Herbivores eat producers and include
butterflies, aphids, snails, mice, rabbits,
fruit-eating bats, gorillas, and cows.
• Omnivores eat producers and
consumers and include corals, crickets,
ants, bears, robins, raccoons, and
humans.
Consumers (cont.)
• Carnivores eat herbivores, omnivores,
and other carnivores and include
scorpions, octopuses, sharks, tuna, frogs,
insect-eating bats, moles, and owls.
• Detritivores consume the bodies of dead
organisms and wastes produced by living
organisms and include termites, wood
lice, and earthworms.
Consumers (cont.)
• Scavengers are detritivores that eat the
bodies of animals killed by carnivores or
omnivores.
• Examples of scavengers include hyenas,
jackals, and vultures.
The Flow of Energy
• Once energy from the environment is
converted into food energy, it can be
transferred to other organisms.
• In an ecosystem, the food energy is
transferred from one organism to another
through feeding relationships.
The Flow of Energy (cont.)
A food chain is a
simple model that
shows how energy
moves from a
producer to one or
more consumers
through feeding
relationships.
A food web is a model of energy transfer that
can show how the food chains in a community
are interconnected.
The Flow of Energy (cont.)
How does energy move through
an ecosystem?
• An energy pyramid is a model that
shows the amount of energy
available in each link
of a food chain.
• The loss of energy at
each level of an energy
pyramid helps explain
why there are always
more producers
than carnivores in
a community.
Cycling Materials
• The law of conservation of matter states
that matter cannot be created or
destroyed, but it can change form.
• Matter is recycled through ecosystems,
changing form along the way.
Cycling Materials (cont.)
Three of the most important pathways of
matter moving through an ecosystem are
described by the nitrogen cycle, the water
cycle, and the oxygen-carbon dioxide cycle.
cycle
from Greek kyklos, means
“circle or wheel”
Cycling Materials (cont.)
How does matter move through
an ecosystem?
The nitrogen cycle describes how nitrogen
moves from the atmosphere to the soil into
the bodies of living organisms and back to
the atmosphere.
All the freshwater on Earth’s surface and in
the bodies of living organisms is recycled
through the water cycle.
Photosynthesis and cellular respiration
cycle carbon dioxide and oxygen through
the ecosystems.
• Organisms are
classified as
producers or
consumers.
• Energy is transferred from one
organism to another through feeding
relationships.
• Matter can be changed into different
forms and cycles through
ecosystems. It cannot be destroyed.
Which model of energy transfer
shows how the food chains in a
community are interconnected?
A. energy pyramid
B. food web
C. nitrogen cycle
D. water cycle
Which consumes the bodies of
dead organisms and wastes
produced by living organisms?
A. carnivore
B. detritivore
C. herbivores
D. omnivore
Which term describes organisms
that cannot make their own food?
A. consumers
B. omnivores
C. producers
D. scavengers
Do you agree or disagree?
3. Sunlight provides the energy at the
base of all food chains on Earth.
4. A detritivore is a type of carnivore.
Humans and Ecosystems
• In what ways do humans affect
ecosystems?
• What can humans do to protect
ecosystems and their resources?
Humans and Ecosystems
• renewable resource
• nonrenewable resource
• resource depletion
Affecting the Environment
• All organisms change the environment in
some way.
• Humans change ecosystems by
replacing wildlife habitats with buildings,
roads, farms, and mines.
• Humans’ use of energy resources such
as coal and natural gas can create
pollutants that affect plant and animal life
in the air, the water, and on land.
Affecting the Environment (cont.)
• Renewable resources are resources
that can be replenished by natural
processes at least as quickly as they
are used.
• Nonrenewable resources are natural
resources that are used up faster than
they can be replaced by natural
processes.
Affecting the Environment (cont.)
• Any resource becomes nonrenewable
if it is used up faster than it can be
replaced.
• Resource depletion—the exhaustion
of one or more resources in an area—
is happening in the United States and
throughout the world.
Affecting the Environment (cont.)
depletion
from Latin deplere, means
“to empty”
The water in the Ogallala Aquifer is
pumped out faster than it is replaced.
Affecting the Environment (cont.)
• The more people can learn about how
their actions affect the environment,
the better their ability to make good
environmental choices in the future.
• The invention of chlorofluorocarbons, or
CFCs, had the unintended consequence
of damaging Earth’s ozone layer.
Affecting the Environment (cont.)
Potential further damage to the ozone
layer was avoided by an international
treaty called the Montreal Protocol which
phased out CFC use worldwide.
This simulation shows what could have
happened to Earth’s ozone layer without
the Montreal Protocol.
Affecting the Environment (cont.)
In what ways do humans affect
ecosystems?
Affecting the Environment (cont.)
• The amount of greenhouse gases
emitted by a person, an organization,
an event, or a product is called its
carbon footprint.
• An increase in greenhouse gases is
contributing to global warming—a rise
in Earth’s average surface temperature.
Protecting the World
Scientists are working to develop
renewable energy resources that can
reduce pollution and people’s dependence
on fossil fuels.
VisionsofAmerica/Joe Sohm/Photodisc/Getty Images
Protecting the World (cont.)
• The U.S. government passes laws,
enforced by the U.S. Environmental
Protection Agency (EPA), to help protect
the environment.
• The EPA also monitors environmental
health, looks for ways to reduce human
impacts, develops plans for cleaning up
polluted areas, and supports
environmental research at universities
and national laboratories.
Protecting the World (cont.)
The 5Rs—restore, rethink, reduce, reuse,
and recycle—are actions everyone can
take to help keep the environment healthy
and to make sure that future generations
of life on Earth have the resources they
need to survive.
Protecting the World (cont.)
How can people protect
ecosystems and conserve
resources?
• Organisms affect their environment
in both positive and negative ways.
• Making and enforcing environmental
laws can protect the environment
from further damage.
• More industries and people are
turning to renewable resources
rather than using nonrenewable
resources.
The McGraw-Hill Companies, Inc./John Flournoy, photographer
Which had the unintended
consequence of damaging Earth’s
ozone layer?
A. CFCs
B. the EPA
C. the Montreal Protocol
D. the Ogalla Aquifer
Which resources are used up
faster than they can be replaced
by natural processes?
A. CFCs
B. nonrenewable
C. renewable
D. unlimited
Which term describes the amount
of greenhouse gases emitted by a
person, an organization, an event,
or a product?
A. carbon footprint
B. global warming
C. ozone layer depletion
D. resource depletion
Do you agree or disagree?
5. Human actions can have unintended
effects on the environment.
6. The only job of the U.S. Environmental
Protection Agency is to enforce
environmental laws.
Key Concept Summary
Interactive Concept Map
Chapter Review
Standardized Test Practice
Organisms interact
with each other and
the environment
around them to obtain
food, shelter, living
space, and other
resources needed for
life.
Lesson 1: Ecosystems
• An ecosystem consists of all the
living and nonliving parts of the
environment in a given area and
the interactions among them.
• Organisms cooperate with,
compete with, or feed on one another to obtain the
resources they need for survival.
• Populations that grow larger than an ecosystem’s
carrying capacity are overpopulated. Overpopulation
can harm the ecosystem by depleting resources.
Extinction—the complete disappearance of a
population from a community—can alter the ways in
which remaining populations interact.
Lesson 2: Energy and Matter
• Energy, usually from the Sun,
moves through an ecosystem
by being transferred from one
organism to another.
• Matter changes form as it
cycles through an ecosystem.
Lesson 3: Humans and Ecosystems
• Human actions contribute to loss of habitat for
plants and wildlife, pollution, and climate change.
• People can educate themselves about
environmental issues; conserve resources by
restoring, rethinking, and reducing resource use;
reusing instead of replacing; and recycling.
The McGraw-Hill Companies, Inc./John Flournoy, photographer
Which refers to all the
populations living in an
ecosystem at the same time?
A. community
B. habitat
C. niche
D. population density
In which type of symbiosis does
one species benefit from the
relationship and the other species
is neither harmed nor benefited?
A. commensalism
B. competition
C. mutualism
D. parasitism
Which term refers to organisms
that use an outside energy source
and make their own food?
A. consumers
B. detritivores
C. herbivores
D. producers
Which type of detritivore eats the
bodies of animals killed by
carnivores or omnivores?
A. herbivore
B. omnivore
C. producer
D. scavenger
Which term describes the
exhaustion of one or more
resources in an area?
A. carbon footprint
B. global warming
C. renewable resource
D. resource depletion
Which is the way a species interacts
with abiotic and biotic factors to
obtain food, find shelter, and fulfill
other needs?
A. community
B. niche
C. predation
D. symbiosis
Which is a close, long-term
relationship between two species
that usually involves an exchange
of food or energy?
A. depletion
B. niche
C. predation
D. symbiosis
In which process is a chemical
such as hydrogen sulfide or
methane used to produce glucose?
A. photosynthesis
B. nitrogen cycle
C. chemosynthesis
D. cellular respiration
Which consumes the bodies of
dead organisms and wastes
produced by living organisms?
A. carnivores
B. detritivores
C. herbivores
D. omnivores
Which resources can be
replenished by natural processes
as quickly as they are used?
A. CFCs
B. fossil fuels
C. nonrenewable
D. renewable