Unit 4 – How Ecosystems Work

Unit 4 – How Ecosystems Work

Energy Flow In Ecosystems

Energy Flow In Ecosystems

Photosynthesis • Plants, algae, and some bacteria

use sunlight to make sugar molecules called carbs

• Carbs – energy rich molecules used to move, grow, and reproduce

• 6CO2 + 6H2O + Solar energy =• C6H1206 + 6O2

• carbon dioxide + water + sun =Sugar/glucose and Oxygen

Exception to the Rule!• Deep-ocean communities have no light and

photosynthesis cannot occur!• The producers in this environment are

bacteria that use hydrogen sulfide present in the water.

• Other underwater organisms eat the bacteria or the organisms that eat the bacteria.

Producer vs. Consumer

• Producer/autotrophs – organism that produces own food

• Consumer/heterotrophs – organism get energy by eating other orgs. (Prods. & Cons.)

Types of Consumers - You Ate What?

• Herbivores – plant eaters– X. rabbits, cows, sheep

• Carnivores – meat eaters– X. Lions, Hawks

• Omnivores – eat all– X. Humans, bears, pigs

• Decomposers – break down dead organisms, allow nutrients to return to the soil– X. bacteria, fungus

Cellular Respiration – Using Energy

• Cell Respiration – breaking down food to yield energy

• Cells absorb oxygen to release food energy

• Basically reverse of photosynthesis

• C6H1206 + 6O2 =

6CO2 + 6H2O + energy

Energy Transfer

• Energy transfers each time one organism eats another

• Food Chain – shows the sequence energy is transferred

• Food Web – a collection of various food chains

Trophic Levels

• Each step in a food chain is a trophic level

• Each level energy is lost as HEAT.

• Only 10% of energy is transferred, so 90% is lost.

• No more that 4-5 per ecosystem

Ecological SuccessionEcosystems are constantly changing. Ecological succession is a gradual process of change and replacement of the types of species in a community.

Primary SuccessionPrimary succession is a type of succession that occurs on a surface where no ecosystem existed before. Primary succession can occur on rocks, cliffs, or sand dunes.

NO SOIL!!!

Pioneer SpeciesA pioneer species is a species that colonizes an uninhabited area and that starts an ecological cycle in which many other species become established.

They pave the way!!!Break down rock and make soil!

Secondary SuccessionSecondary succession occurs on a surface where an ecosystem has previously existed. Secondary succession can occur in ecosystems that have been disturbed or disrupted by humans, animals, or by natural process such as storms, floods, earthquakes, or volcanic eruptions.

Climax Community – A.Sisters Video

Old Field SuccessionOld-field succession is a type of secondary succession that occurs when farmland is abandoned. When a farmer stops cultivating a field, grasses and weeds quickly grow and cover the abandoned land.Over time, taller plants, such as perennial grasses, shrubs, and trees take over the area.