5.1 – Energy Flow in Ecosystems

Warm Up

How do you get energy? How is this similar and different to the ways that other organisms get their energy? Give specific examples. - Write in complete sentences. At least 5 lines.

Life Depends on the Sun

Photosynthesis – process where plants use energy from the sun to make sugar; this allows energy from the sun to enter the ecosystem

Photosynthesis Equation:

Carbon Dioxide (CO2) + Water (H2O) + Solar Energy

Sugar (C6H12O6) + Oxygen (O2)

Written as

CO₂ + H₂O + sunlight -- C₆H₁₂O₆ + O₂

AND Carbon dioxide + water +sunlight

glucose (sugar) and oxygen

From Producers to Consumers Producer – organism that makes its own

food; also known as autotrophs

Consumer – organism that gets its energy by eating other organisms; also known as heterotrophs

Producers get their energy directly from the sun and consumers get their energy indirectly from the sun.

Exception to the Rule: Deep-Ocean Ecosystems Deep-ocean communities exist

where there is no light. Bacteria living near hydrothermal vents make their own food through a process called chemosynthesis. These bacteria are the producers in this community and make it possible for worms, crabs, mussels, and barnacles to exist there.

What Eats WhatTypes of Consumers in an Ecosystem

Energy Source ExamplesHerbivore producers cows, sheep, deer,

and grasshoppersCarnivore other consumers lions, hawks, snakes,

spiders, alligators, and whales

Omnivore both producers and consumers

Bears, pigs, gorillas, rats, raccoons, cockroaches, and humans

Decomposer breaks down dead organism

fungi and bacteria

Scavenger dead consumers vultures, hyenas, crows, flies

Cellular Respiration: Burning the Fuel

Cellular Respiration – breaking down food to yield energy

Respiration Equation:

Sugar (C6H12O6) + Oxygen (O2) Carbon Dioxide (CO2) + Water (H2O) + Energy (ATP)

This is the opposite of the photosynthesis equation!

Also written as

CR C₆H₁₂O₆ + O₂ CO₂ +H₂O + Energy

(ATP) Opposite of

CO₂ + H₂O + sunlight -- C₆H₁₂O₆ + O₂

Phot

Check Your Understanding

Why do you think it is important that photosynthesis and respiration are opposite processes?

Energy Transfer

Each time one organism eats another organism, a transfer of energy occurs.

We can trace the transfer of energy as it travels through an ecosystem by studying food chains, food webs, and trophic levels.

Food Chains and Food WebsFood Chain – a sequence in which

energy is transferred from one organism to the next as each organism eats another organism

Food Web – shows many feeding relationships that are possible in an ecosystem

Collins I3 lines What happened as you moved

through the food chains yesterday? Why do you start back at 10,000

energy points each time you went back to producer?

Who is involved in every food chain?

Exit Ticket

Give me three things you liked about class yesterday and today

HW

Complete the handout tonight

Trophic Levels Trophic Level – each step through which energy

is transferred

Energy Loss Each time energy is transferred, some is lost as heat.

Organisms use much of the remaining energy to carry out the functions of living things, such as producing new cells, regulating body temperature, and moving.

About 90% of the energy at each trophic level is lost and only 10% can be transferred to the next trophic level.

Quarternary Consumer (4)

Tertiary Consumer (3)

SecondaryConsumer (2)

Primary Consumer (1)

Producer

Energy Pyramids

Energy Pyramid – shows the loss of energy from one trophic level to the next

How Energy Loss Affects an Ecosystem Because so much energy is lost at

each level, there are fewer organisms at higher trophic levels.

Loss of energy from trophic level to trophic level limits the number of trophic levels in an ecosystem.

5.2 –The Cycling of Materials

Warm Up

What are three products that you recycle? Where do these products come from? Where do these products go after you recycle them?

Write in complete sentences. At least 5 lines.

The Carbon Cycle Carbon Cycle – process by which carbon is cycled

between the atmosphere, land, water, and organisms

How the Carbon Cycle Works: Producers convert carbon dioxide in the atmosphere into

carbohydrates during photosynthesis.

When consumers eat producers they obtain carbon from the carbohydrates.

As consumers break down food during cellular respiration, they release carbon dioxide into the atmosphere.

The Carbon Cycle Continued… Carbon can also be stored:

Some is converted into energy storing molecules like fats and oils which are not released until the organism dies.

Some is converted into carbonates, which make up bones and shells.

Some forms limestone rock.

Some is found in fossils and fossil fuels.

How Humans Can Affect the Carbon Cycle When we burn fossil fuels we release

carbon dioxide into the atmosphere.

In the year 2000, cars were the source of 1/3 of all of the carbon dioxide emitted in the U.S.

Increased levels of carbon dioxide in the atmosphere may lead to global warming.

The Nitrogen Cycle

Nitrogen makes up 78% of the gases in the atmosphere.

Most organisms cannot use atmospheric nitrogen. It must be altered, or fixed, before organisms can use it.

Nitrogen-fixing Bacteria – bacteria that can fix atmospheric nitrogen into nitrogen compounds

The Nitrogen Cycle Continued… How the Nitrogen Cycle Works:

Nitrogen-fixing bacteria live in nodules on the roots of plants called legumes. Legumes include beans, peas, and clover.

Nitrogen produced by the bacteria is released into the soil.

Plants get their nitrogen from the soil. Animals get their nitrogen directly or indirectly from plants.

Decomposers and the Nitrogen Cycle Nitrogen is released from waste,

corpses, and other parts of organisms when they are broken down by decomposers.

Nitrogen is then released back into the atmosphere.

The Phosphorus Cycle Phosphorus Cycle – the movement of

phosphorus from the environment to organisms and then back to the environment

How the Phosphorus Cycle Works: Phosphorus enters water or soil when rocks erode.

Plants get phosphorus from the soil. Animals get their phosphorus directly or indirectly from plants.

Phosphorus is released back into the soil through animal waste or when plants or animals are decomposed.

Fertilizers and the Nitrogen and Phosphorus Cycles Fertilizers which are used to maximize plant

growth contain nitrogen and phosphorus.

If used in excess, fertilizers can enter terrestrial and aquatic ecosystems through runoff.

In aquatic ecosystems excess nitrogen and phosphorus can cause algal blooms which can deplete the ecosystem of oxygen, causing fish and other organisms to die.

Review of Cycles Work in groups of 3:

Each person will be assigned a different cycle: carbon, nitrogen, or phosphorus.

Write down everything you know about your cycle. See what you can remember. Do not use your notes.▪ You may use bullets for your answers. ▪ You should try to come up with a minimum of 5 things

you can tell me about your cycle. Switch papers. Have the other members of your

group add or make corrections to what you wrote. Switch again and keep adding/ correcting. Have a group discussion,

5.3 – How Ecosystems Change

Warm Up

What would happen to the practice fields around Sun Valley High School if no one mowed or took care of them for a week? A month? A year? 10 years? 100 years? Describe the changes you would see over time. – Write in complete sentences. At least 5 lines.

Succession Ecological Succession – a gradual process of

change and replacement of some or all species in a community; may take hundreds or thousands of years

Types of Succession

Primary Succession – type of succession that occurs on a surface where no ecosystem existed before▪ Examples: rocks, sand dunes, newly formed volcanic islands

Secondary Succession – more common; occurs on a surface where an ecosystem has previously existed▪ Examples: a mowed lawn, a forest after a fire

Succession Continued…

Pioneer Species – the first organisms to colonize any newly available area and begin the process of ecological succession

Climax Community – a final, stable community Example: a forest with large, mature

trees

Fire and Secondary Succession Natural fires are the cause of secondary

succession in some communities.

Some tree species can only release their seeds after they have been exposed to intense heat.

Minor forest fires remove the accumulations of brush and deadwood that would otherwise contribute to major fires.

Old-field Succession

This occurs when farmland has been abandoned.

Once abandoned grasses and weeds grow rapidly.

Over time taller plants and even trees will grow.

Primary Succession On new islands created by volcanic eruptions, in

areas exposed when a glacier retreats, or any other surface that has not previously supported life, primary succession can occur.

Primary succession is much slower than secondary because there is no soil.

The first species to colonize bare rock will probably be lichens and bacteria.

Over time the pioneer species will break down the rock and form soil.

Check Your Understanding

Give an example of primary succession in a city.