Table of Contents • Energy Flow in Ecosystems • Cycles of Matter • Biogeography • Biomes • Aquatic Ecosystems
Energy Roles • Recall that a self-sustaining ecosystem has four characteristics: • 1. A constant source of energy (usually the sun) • 2. Transfer of energy into organic compounds • (usually through photosynthesis) • 3. Interactions between biotic factors • (predator/prey, mutualism, commensalism) • 4. Cycling of materials (water cycle, nitrogen • cycle, oxygen/carbon dioxide cycle, • nutrient cycle)
Energy Roles • In order for these four factors to be met, organisms within an ecosystem must fit into one of three roles: Decomposers Producers Consumers
Producers • Producers —organisms that make(produce) their own food. • -Usually, producers use energy from the sun to turn waterand carbon dioxide into sugar. • -This process is called photosynthesis. • -Producers include: Plants Algae Cyanobacteria
Consumers • Consumers —organisms that get energy by feeding on other organisms. Three types: • Herbivores —eat only plants • Carnivores —eat only animals • Omnivores —eat both plants • and animals
- Energy Flow in Ecosystems Consumers • Click the Video button to watch a movie about consumers.
Decomposers • Decomposers —break down wastes and dead organisms and return raw materials to the ecosystem. • Decomposers include mostly bacteria and fungi such as mushrooms.
Food Chains and Food Webs • To sustain any ecosystem, energy must be transferred through the many organisms that live in the ecosystem. • The movement of energy through an ecosystem can be shown in diagrams known as food chains and food webs. • Food chain —shows a series of events in which one organism eats another and obtains energy. Food chains always start with a producer. Each organism that follows is known as a first, second, and third level consumers etc. Food chains show just one path of energy. C3 C2 C1
Food Webs Who is the only C5 consumer? Is there a C7? • Food webs —show the many overlapping food chains in an ecosystem. In a food web, an organism can play more than one role. Can you find this food chain in the food web? Can you find an animal that is both a C2 and C3 consumer?
- Energy Flow in Ecosystems Food Chains and Food Webs • The movement of energy though an ecosystem can be shown in diagrams called food chains and food webs.
Food chain/food web Flip chart
Energy Pyramids • Energy Pyramids show the amount of energy that moves from one feeding level to another in a food web. • The most amount of energy is available at the producer level. • The amount of energy decreases at each level.
Only 10% of the energy available at one level is transferred to the next level. • The other 90% is used • by the organism or lost • to the environment in • the form of heat. • Therefore, each level • can support fewer • and fewer organisms.
Key Terms: Examples: energy pyramid food web producers - Energy Flow in Ecosystems Building Vocabulary • A definition states the meaning of a word or phrase by telling about its most important feature or function. After you read the section, reread the paragraphs that contain definitions of Key Terms. Use all the information you have learned to write a definition of each Key Term in your own words. Key Terms: Examples: food chain consumer herbivore omnivore carnivore scavenger In a food chain, a consumer could be an herbivore, an omnivore, or a carnivore, including a scavenger. An energy pyramid shows how much energy moves from one level to another in a food web, beginning with the producers. decomposer Decomposers are nature’s recyclers.
- Energy Flow in Ecosystems Links on Food Chains and Food Webs • Click the SciLinks button for links onfood chains and food webs.
Cycles of Matter • Remember that one of the four characteristics of a self-sustaining ecosystem is the cycling of matter. This happens through three main processes: • The Water Cycle—the process by which water • moves from the Earth’s surface to the • atmosphere and back. • The Carbon/Oxygen Cycle—carbon dioxide • and oxygen are recycled through processes that • are linked together by producers and consumers. • The Nitrogen Cycle—nitrogen cycles from the • air, to the soil, into living things and back into the air.
- Cycles of Matter The Water Cycle • The processes of evaporation, condensation, and precipitation make up the water cycle.
- Cycles of Matter Water Cycle Activity • Click the Active Art button to open a browser window and access Active Art about the water cycle.
- Cycles of Matter The Carbon and Oxygen Cycles • In ecosystems, the processes by which carbon and oxygen are recycled are linked. Producers, consumers, and decomposers play roles in recycling carbon and oxygen. What do you notice about the amounts of carbon dioxide and oxygen in this diagram?
- Cycles of Matter The Nitrogen Cycle • In the nitrogen cycle, nitrogen moves from the air to the soil, into living things, and back into the air.
- Cycles of Matter Sequencing • Sequence is the order in which a series of events occurs. As you read, make a cycle diagram that shows the water cycle. Write each event of the water cycle in a separate oval. The Water Cycle Water evaporates. Precipitation runs off or becomes groundwater. Clouds form. Precipitation falls.
Biogeography • Biogeography is the study of where organisms live. • From the Greek words: • Bio = lifeGeo = earthGraph = description • Biogeographers also try to figure out why they live there and how they got there. • One factor that affects how species are spread out on the Earth is Continental Drift —the movement of the continents on top of large continental plates of rock.
Continental Drift • 225 million years ago = all continents were joined together in one large land mass called Pangea. • 180-200 million years ago = Pangea broke into two large land masses known as Laurasia and Gondwanaland • 135 million years ago = Laurasia and Gondwanaland begin to break apart into the seven continents seen today. They continue to drift apart every year.
- Biogeography Continental Drift • One factor that has affected how species are distributed is the motion of Earth’s continents.
- Biogeography Continental Drift Activity • Click the Active Art button to open a browser window and access Active Art about continental drift.
Maps like this one (by Alfred Wegener, 1915) support the idea that the continents were once connected. They show how identical fossils of certain plants and animal that have been found on two sides of an ocean could have gotten there when the continents were joined.
Dispersal • Dispersal —the movement of organisms from one place to another. It is caused by: • Wind —disperses light weight organisms such as • seeds, spores, tiny insects or spiders • Water —disperses organisms that float such as • coconuts, leaves or animals floating on them • Other living things —many things are carried by other • living things to new places—either • accidentally or intentionally
- Biogeography Limits to Dispersal • The typical weather pattern in an area over a long period of time is the area’s climate.
Limits to Dispersal • Three factors limit dispersal. • Physical barriers —water, mountains and deserts • can be hard to cross. • Competition —if one species out-compete • another, the other must move somewhere • else to survive. • Climate —only certain species can survive in certain • climates. This limits where they can disperse • to. Places with similar climates have species • that occupy similar niches.
- Biogeography Relating Cause and Effect • As you read, identify three causes of dispersal. Write the information in a graphic organizer like the one below. Causes Wind Effect Dispersal of species Water Living things, including humans
Biomes • Biome —a group of land ecosystems with similar • climates and organisms. • Biomes are determined by their climate: meaning their and precipitation amounts and temperature. • There are six major biomes in the world. • rainforestdeciduous forest • desertboreal forest • grasslandtundra
Land Biomes and their Climates • Biome Ave. Yearly Rainfall Ave. Yearly Temp. • Rainforest 200-450 cm 25oC to 28oC . • Deserts less than 25 cm 24oC to 40oC . • Grasslands 25-75 cm 0oC to 25oC . • Deciduous • forest 75-125 cm 6oC to 28oC . • Boreal • forest 35-75 cm -10oC to 14oC . • Tundra less than 25 cm -25oC to 4oC .
Biome Map Rainforest Deciduous Forest Boreal Forest Grasslands Desert Tundra
- Biomes Rain Forest Biomes: Two Types • Tropical rain forests are wet, warm biomes located near the equator. They support more than ½ of all plant and animal species on the Earth.
Tropical Rainforests • Characteristics: • Warm all year with at least 200 cm of rain/year • Trees do not lose their leaves, creating a dense canopy that supports much of the animal life
- Biomes Rain Forest Biomes • Temperate rain forests receive 300 cm of rain and have moderate temperatures. They are located in northeast U.S. • Huge cedars, redwoods and firs grow there.
- Biomes Desert Biomes • A desert is an area that receives less than 25 cm of rain per year. Not all deserts are hot. Some are hot in the day and cold at night (Sahara, Africa). Others are cold all the time (Gobi, Mongolia).
- Biomes Grassland Biomes • A grassland is an area that is populated mostly by grasses and other nonwoody plants. Grasslands close to the equator are called savannas. They have shrubs and trees along with grass. Most have fertile soil and grow good crops.
- Biomes Deciduous Forest Biomes • Many of the trees in the deciduous forest are deciduoustrees, which shed their leaves and grow new ones each year. A deciduous forest receives at least 50 cm of precipitation each year. Temperatures vary greatly through the year.
- Biomes Deciduous Forests • Click the Video button to watch a movieabout deciduous forests.
- Biomes Boreal Forest Biomes • Most of the trees in the boreal forest are coniferous trees, trees that produce their seeds in cones and have leaves shaped like needles. Winters in the boreal forest are cold and very snowy, but summers are warm and rainy enough to melt all the snow. This biome is also know as the Taiga.
- Biomes Tundra • The tundra is an extremely cold and dry biome. Most of the soil in the tundra is permafrost, which is frozen all year. Winters are long and cold with almost no daylight. Summers are short and cool with 24 hrs. of daylight.
- Biomes Mountains and Ice • Some areas of land are not part of any major biome. These areas include mountain ranges and land that is covered with thick sheets of ice.
- Biomes Earth’s Biomes Activity • Click the Active Art button to open a browser window and access Active Art about Earth’s biomes.
- Biomes Biome Climates • An ecologist collected climate data from two locations. The graph shows the monthly average temperatures in the two locations. The total yearly precipitation in Location A is 250 cm. In Location B, the total yearly precipitation is 14 cm.