How do living things interact with and depend on the other parts of an ecosystem?

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.

1. An ecosystem contains both living and nonliving things.

2. All changes in an ecosystem occur over a long period of time.

3. Changes that occur in an ecosystem can cause populations to become larger or smaller.

Do you agree or disagree?

4. Some organisms have relationships with other types of organisms that help them to survive.

5. Most of the energy used by organisms on Earth comes from the Sun.

6. Both nature and humans affect the environment.

Do you agree or disagree?

• ecosystem

• abiotic factor

• biotic factor

• population

Ecosystems and Biomes

• community

• biome

• succession

Ecology is the study of how organisms interact with each other and with their environments.

Every organism on Earth lives in an ecosystem—the living and nonliving things in one place.

Different organisms depend on different parts of an ecosystem to survive.

What are ecosystems?

What are ecosystems?

What is an ecosystem?

Abiotic factors are the nonliving parts of an ecosystem.

Important abiotic factors include water, light, temperature, atmosphere, and soil.

The types and amounts of abiotic factors in an ecosystem help to determine which organisms can live there.

Abiotic Factors

All organisms need water to live, but some need more water than others.

The amount of light available and the temperature of an ecosystem can also determine which organisms can live there.

Different ecosystems contain different amounts and types of nutrients, minerals, and rocks in the soil.

Abiotic Factors

All organisms need water to live, but some need more water than others.

The amount of light available and the temperature of an ecosystem can also determine which organisms can live there.

Different ecosystems contain different amounts and types of nutrients, minerals, and rocks in the soil.

Abiotic Factors

atmosphereScience Use the mix of gases surrounding a planetCommon Use a surrounding influence or feeling

Very few living things can survive in an ecosystem without oxygen in the atmosphere.

Biotic factors are all of the living or once-living things in an ecosystem.

A population is made up of all the members of one species that live in an area.

Organisms in a population interact and compete for food, shelter, and mates.

A community is all the populations that live together in the same place.

Biotic Factors

A biome is a large region on Earth with a specific climate, physical features, plants, and other organisms.

Biomes contain ecosystems, populations, and communities, as well as specific biotic and abiotic factors.

All biomes are part of the biosphere—the part of Earth that supports life—and can be described as either terrestrial or aquatic.

Biotic Factors

Ima

ge by R

eto S

tockli, NA

SA

/Go

ddard

Spa

ce Fligh

t Cen

ter. E

nha

ncem

ents b

y Ro

bert S

imm

on

Terrestrial means related to land, and aquatic means related to water.

Terrestrial biomes include forests, deserts, tundra, and grasslands.

Aquatic biomes include saltwater areas and freshwater areas.

Biomes, like communities, can affect each other.

Biotic Factors

Biotic Factors

What is a biome?

Changes in the environment are caused by both natural processes and human actions.

Changes in an environment can occur slowly or rapidly and can have positive or negative effects.

What happens when environments change?

A volcanic eruption can cause sudden change in an ecosystem.

Succession is the gradual change from one community to another community in an area.

What happens when environments change?

What happens when environments change?

Which biotic and abiotic factors changed after the Mount St. Helens eruption?

A. abiotic factorsB. biotic factorsC. biomesD. populations

Which of these refers to the nonliving parts of an ecosystem?

A. ecosystemB. biosphereC. communityD. biome

Which of these refers to all the populations that live together in the same place?

A. succession

B. population C. interaction D. community development

The gradual change from one community to another community in an area is called what?

Learning Goal

Students will be able to explain the relationships among organisms in ecosystems. Compare and contrast mutualism,

predation, parasitism, competition and commensalism

Determine how various limiting factors impact native populations Food, water, shelter, space, disease,

parasitism, predation, nesting sites

• limiting factor

• biotic potential

• carrying capacity

• habitat

Populations and Communities

• niche

• symbiotic relationship

The area in which a population lives can be very large, such as the population of all the fish in the ocean, or very small, like fish in a lake.

If either biotic or abiotic factors that affect an organism change, that organism’s population can also change.

Populations

The area a population lives in can be large or small.

Sometimes the size of a population changes because the ecosystem changes.

Population density describes the number of organisms in the population relative to the amount of space available.

If a population is very dense, organisms might have a hard time finding enough resources to survive.

Populations

The size of a population can change in different ways.

Limiting factors are factors that can limit the growth of a population.

Biotic potential is the potential growth of a population if it could grow in perfect conditions with no limiting factors.

Carrying capacity is the largest number of individuals that can survive in an area over a long time.

The limiting factors of an area determine the area’s carrying capacity.

Populations

Overpopulation is when a population’s size grows beyond the ability of the area to support it.

This often results in overcrowding, a lack of resources, and an unhealthy environment.

Populations

Communities

All the populations in the same area interact as a community.

Communities

How do the different populations in a lake interact with each other?

Some populations might compete with each other for resources and space.

A symbiotic relationship is one in which two different species live together and interact closely over a long period of time.

These relationships can be beneficial to both organisms, beneficial to one and harmful to the other, or beneficial to one and neutral to the other.

Symbiotic Relationships

Mutualism—two species in a community benefit from the relationship.

Parasitism—one species (the parasite) benefits while another (the host) is harmed.

Commensalism—one species benefits and the other is neither helped nor harmed.

Types of Symbiotic Relationships

Symbiotic Relationships

What is one example of a symbiotic relationship?

A. limiting factorB. biotic potentialC. population densityD. carrying capacity

If a population’s rate of birth is as high as it can be while its death rate is as low as it can be, that population has reached which of these?

A. biotic potentialB. population C. limiting factorsD. habitat

Which of these determines an area’s carrying capacity?

A. carrying capacityB. habitatC. biotic potentialD. limiting factor

All of the populations in a community share which of these?

• producer

• consumer

• food chain

• food web

• energy pyramid

Energy and Matter

Organisms get energy from food that they make using light or chemical energy or by eating other organisms.

When one organism eats another, the energy in the organism that is eaten is transferred to the organism that eats it.

Energy Flow

Energy travels through organisms, populations, communities, and ecosystems in a flow.

When energy moves in a flow it does not return to its source, as it does in cycles.

Energy Flow

Scientists classify organisms by the way they get the energy they need to survive.

Some organisms, such as plants, are able to capture the Sun’s energy directly and convert it into energy-rich sugars that they use for food.

Organisms and Energy

Light energy is changed to food energy by a process called photosynthesis.

A few organisms are able to capture energy from chemicals in the environment and make food by a process called chemosynthesis.

Other organisms cannot capture energy from sunlight or chemicals and must obtain their energy by eating food.

Organisms that cannot make their own food using the Sun must depend on organisms that can.

Organisms and Energy

Organisms and Energy

producerfrom Latin producere, means “to lead”

Producers change the energy available in their environment into food energy that they use to live and reproduce.

Organisms and Energy

How does energy move from a producer to other organisms?

Consumers use the energy and nutrients stored in other organisms for living and reproducing.

Consumers are classified as herbivores, omnivores, carnivores, or detritivores, based on their diet.

Herbivores are animals that eat only producers, such as plants.

Organisms and Energy

Omnivores, such as human beings, are animals that eat both producers and other consumers.

Carnivores, such as lions, eat only other consumers.

Detritivores, including some insects, fungi, worms, bacteria, and protists, eat dead plant or animal material.

Organisms and Energy

A food chain models how food energy moves from the environment to several organisms.

Modeling Energy Flow

Each stage of a food chain has less available food energy than the last one, because some food energy is converted to thermal energy and moves to the environment.

A food web is a model that shows several connected food chains.

Modeling Energy Flow

Food Web

Food chains and food webs are models used to help understand how energy travels through a community.

Terrestrial and aquatic organisms can interact within a food chain or food web.

Food webs show that food energy can move through several different pathways.

Modeling Energy Flow

Modeling Energy Flow

Compare a food chain with a food web.

Modeling Energy Flow

Compare a food chain with a food web.

An energy pyramid shows the amount of food energy available at each level of a community.

More food energy is available at the “base” of an energy pyramid, where producers are.

Modeling Energy Pyramids

Food energy from producers moves into consumers at the next level.

At each level of the pyramid, the amount of usable food energy decreases.

The top level of a food pyramid usually shows the carnivores in an ecosystem.

Modeling Energy Pyramids

This energy pyramid shows how energy flows from producers to consumers.

Food, vitamins, minerals, and water that you need to live are examples of matter.

Matter is the physical material that makes up the world around you.

Most of the matter in your body is water, but your body also contains matter in other forms such as carbon and oxygen.

Matter Cycles

Like energy, matter is not created or destroyed but is transferred through the environment.

Unlike energy, matter moves in cycles.

Matter Cycles

Water Cycle

Liquid water evaporates from oceans, rivers, and other bodies of water.

The water vapor, which is a gas, rises into the atmosphere, where it condenses and falls as rain or snow.

Water Cycle

Water moves across the surface of Earth in lakes, streams, and rivers, soaks into the ground, or is taken in by organisms, before eventually being released again, continuing the cycle.

Water Cycle

What forms does water take in the water cycle?

Water Cycle

Oxygen also cycles through the environment.

Producers release oxygen gas and consumers take it in.

Plants release oxygen as a waste product of photosynthesis.

The oxygen enters the atmosphere, and many consumers take it in when they breathe.

Oxygen Cycle

When organisms exhale, they release carbon dioxide, which contains oxygen and is a by-product of cellular respiration.

Some producers take in carbon dioxide, and the cycle continues.

Oxygen Cycle

Carbon, a fundamental building block for all living things, also cycles through the environment.

When producers use carbon dioxide during photosynthesis, carbon is removed from the atmosphere.

Consumers eat these producers and release carbon back into the environment as a waste product

Producers again remove the carbon from the atmosphere as they continue making food, and the cycle continues.

Carbon Cycle

Lesson 3 – LR1

A. producersC. omnivores

B. consumers D. herbivores

Which type of organism changes the energy available in its environment into food energy it uses to live?

Lesson 3 – LR2

A. an energy pyramid

B. a matter cycle

C. a food web

D. an energy flow

Which type of model do scientists use to show several connected food chains?

Lesson 3 – LR3

A. carbon dioxide cycle

B. energy cycle

C. vapor cycle

D. carbon cycle

Three matter cycles include the oxygen cycle, water cycle, and which of these?