How Ecosystems Work

Big Ideas The flow of energy, cycling of materials, and ecological succession combine to affect how an ecosystem works. Organisms need energy to survive. Some organisms can convert directly from the sun, others get their energy indirectly from the sun. The cycling of materials such as carbon, nitrogen, water and phosphorous keep nutrients balanced in an ecosystem.

Section 1: Energy Flow In Ecosystems Describe how energy is transferred from the sun to producers and then consumers Explain what a food chain and food web are Explain why an energy pyramid is a representation of trophic levels Terms: photosynthesis, producer, consumer, decomposer, cellular respiration, food chain, food web, trophic levels

What makes an ecosystem like this “work?”

Life Depends On The Sun Average Star 93 million miles away Nuclear Fusion No Sun, No Life

Life Depends on the Sun ALL organisms need a constant supply of energy or they die Why do plants grow upwards?

Life Depends on the Sun The ultimate source of almost all energy for organisms is the SUN. What did you eat? (Nuclear Powered?) Only some deep sea creatures do not get energy from sun Mmmm, solar energy tastes good!

Life Depends on the Sun Photosynthesis: plants use the suns energy, water and CO2, to make energy. Base of ALL food chains

Almost all organisms depend either directly or indirectly on photosynthesis

How do other Organisms Use Energy Most organisms spend large amounts of time/energy in search of food and a mate.

How do other Organisms Use Energy Cellular Respiration: processes of breaking down food to yield energy Gives energy to walk, read, grow, think, run, fight diseases Excess stored as fat

Glucose (sugar) + Oxygen yields carbon dioxide, water and energy REACTANTS PRODUCTS

Energy Transfer in an Ecosystem Producer: an organism that makes it own food. Plants Autotrophs, self-feeders Use sunlight Base of all food chains

From Producer to Consumer Consumer: gets it energy by eating producers or other consumers Heterotrophs Indirectly solar powered

Types of Consumers Herbivore: eats only producers (vegetarian) Cows, sheep, deer, grasshopper, mice, rabbits

Types of Consumers Carnivore: eats other consumers Lion, hawks, snakes, alligator, whales

Types of Consumers Omnivore: eats both producers and consumers Bears, pigs, raccoons and most humans

Types of Consumers Decomposer: breaks down dead decaying organisms Critical to ecosystem health Returns nutrients Fungus, bacteria

Energy Transfer Each time one organism eats another, energy is transferred Ecosystems are all about energy flowing from one organism to another

Energy Transfer Who are the producers? Consumers? Herbivores? Carnivores? Omnivores? Decomposers? Where does the energy start?

Energy Transfer Food Chain: linear sequence in which energy is transferred from one organism to another Starts with producers

Energy Flow Food Web: shows many feeding relationships that are possible in a ecosystem More complex and realistic

Energy Flow Trophic Level: each step which energy is transferred

Energy Pyramid

Energy Flow Why are there fewer organisms at the top? (Why fewer Hawks than the other birds they prey on) Why aren’t there more than 4-5 trophic levels in a energy pyramid?

Energy Flow At each trophic level about 90% of energy is lost Cellular respiration Lost to body heat and carry out living

Energy Flow Why are there fewer organisms at the top? (Why fewer bears than the fruit they feed on) Why aren’t there more than 4-5 trophic levels in a energy pyramid?

Section 1 Review Describe how energy is transferred from the sun to producers and then consumers Explain what a food chain and food web are Explain why an energy pyramid is a representation of trophic levels Terms: photosynthesis, producer, consumer, decomposer, cellular respiration, food chain, food web, trophic levels

Section 2: Cycling Matter Explain how matter is cycle in the carbon, nitrogen and phosphorous cycles. Identify ways that humans are impacting the carbon cycle. Explain how excess use of fertilizer can lead to impacts for the nitrogen and phosphorous cycles. Terms: carbon cycle, nitrogen cycle, nitrogen-fixation, phosphorous cycle

The Cycling of Material Just like water – water cycle – other nutrients also move throughout the earth Biogeochemical cycles CARBON NITROGEN PHOSPHOROUS

Carbon Cycle Carbon Cycle: process by which carbon is cycled between the atmosphere, land, water and organisms

Carbon Cycle Carbon “duct-tape” of life Carbohydrates in cellular respiration Fossil Fuels (coal, oil, natural gas) made from ancient dead decayed organisms… ancient carbon

Burning Fossil Fuels leads to what problems? Burn anything that was/is living and what product do you get?

Carbon Cycle What is a product of cellular respiration? What do you breathe out?

Carbon can move quickly or very slowly through cycle

Nitrogen Cycle Nitrogen Cycle: process by which nitrogen is cycled through the atmosphere, bacteria and other organisms.

Nitrogen Cycle Nitrogen Needed by all organisms for build cells (proteins) 78% of atmosphere (unusable by most organisms) Decomposers break down animal waste releasing nitrogen to soil

Nitrogen Cycle Nitrogen Fixation: bacteria that are able to take nitrogen in air and make it useful as plant fertilizer On roots of plants Critical to life

Phosphorous Cycle Phosphorous Cycle: the movement of phosphorous from the environment to organisms and back.

Phosphorous Cycle Phosphorous: Teeth and bones Nutrient for plant growth Found in rocks and soil Animal wastes contain phosphorous

Too Much Nitrogen and/or Phosphorous Fertilizers put on plants contain both nitrogen and phosphorous Too much fertilizer runs off into water Causes Algae blooms

Algae blooms like this caused by excess nitrogen and phosphorous can kill fish and create “dead zones”

Section 2 Review Explain how matter is cycle in the carbon, nitrogen and phosphorous cycles. Identify ways that humans are impacting the carbon cycle. Explain how excess use of fertilizer can lead to impacts for the nitrogen and phosphorous cycles. Terms: carbon cycle, nitrogen cycle, nitrogen-fixation, phosphorous cycle

Section 3 How Ecosystems Change Describe the types of ecological succession Explain what pioneer species are Terms: ecological succession, primary succession, secondary succession, pioneer species

Ecological Succession Ecosystems constantly are changing (some fast some slowly) Young Forests vs. Old Forest Quick change like fire, or volcanic eruption

Ecological Succession Ecological Succession: the gradual change and replacement of some or all species in a community Neighborhood changes over time

Ecological Succession Primary Succession: occurs on a surface where no ecosystem existed before (FIRST) Rocks, sand dunes Uncommon!

Ecological Succession Secondary Succession: occurs on a surface where an ecosystem has previously existed More common Land Disturbed by humans, other animals Flood, fire, volcano

Secondary ecological succession after a fire on the left Fires are a natural part of many forest ecosystems

Ecological Succession Pioneer Species: first organisms to colonize a newly available land Lichens, bacteria, small plants often pioneers

Pioneer species in a parking lot crack

Ecological Succession Climax Community: final stable community. Continues to change in small ways, but fairly stable if undisturbed

Section 3 Review Describe the types of ecological succession Explain what pioneer species are Terms: ecological succession, primary succession, secondary succession, pioneer species

Chapter 5 Review The flow of energy, cycling of materials, and ecological succession combine to affect how an ecosystem works. Organisms need energy to survive. Some organisms can convert directly from the sun, others get their energy indirectly from the sun. The cycling of materials such as carbon, nitrogen, water and phosphorous keep nutrients balanced in an ecosystem.

How is energy transferred from one organism to another? Chapter 5 Review Questions How is energy transferred from one organism to another? What role to producers play? Consumers? Decomposers? What is the difference between a herbivore and an omnivore? Give an example of energy flow in a food chain.