Ecosystems

Life Science

Ecosystems

By Barbara Keith

Ecosystems   

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An organism is any living thing (plant or animal) All organisms are made up of cells. The cell is the smallest unit of life. Organisms with only 1 cell = unicellular Organisms with many cells = multicellular

Animal Cell

Cells All cells contain these major structures: 

Cell membrane - soft, flexible outside covering that controls what goes in and comes out of the cell (gatekeeper)

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Cytoplasm - the gel-like fluid that fills most of a cell. All the organelles are found here.

Organelles of the cell 

Nucleus - controls everything the cell does

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Vacuole – stores food, water, waste for the cell

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Mitochondria - energy is made here (Remember the Mighty Mitochondria)

Ecosystem 

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An Ecosystem contains all the living (organisms) and non-living parts in the surrounding environment. Make foldable showing: Ecosystems are made up of: Biotic factors = living things Abiotic factors = non-living things

Biotic Factors 

All the living things in an ecosystem

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Populations – all members of one kind of organism that live in a particular area. (This includes microorganisms which are too small to be seen without a magnifier.) Communities – groups of different populations of organisms

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Population vs. community 

Population

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Community

Abiotic factors 

The non-living things in an ecosystem Temperature, water, soil, air, sunlight

Types of Ecosystems – We are going to make a foldable to show both Terrestrial = Land  

Forests Grasslands

Aquatic = Water

• Freshwater • Saltwater • Estuaries

Terrestrial Ecosystems

Forests 

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Many trees, shrubs, grasses and ferns A variety of animals live here Gets more rain than grasslands Temperatures vary based on location of forest

Terrestrial Ecosystems

Grasslands    

Fertile (rich) soil Covered with tall grasses Temperatures vary depending on location Common animals = prairie dogs, bison, grasshoppers

Terrestrial Ecosystems Wetlands  Clean the water  Reduce flood risks  Provide fish and wildlife habitat

Aquatic Ecosystems

Lakes and Ponds  

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Bodies of freshwater surrounded by land. Ponds are usually smaller and shallower and temperature of water is the same at top and bottom. Plants and algae grow here. Different kinds of fish, amphibians, ducks, turtles, beavers

Aquatic Ecosystems

Oceans Large bodies of salt water divided by continents  Most organisms live where the ocean is shallow (from shoreline to continental shelf) {Warmer water and sunlight} Plankton, jellyfish, fish, crabs, coral 

Aquatic Ecosystems

Estuaries    

Found where the freshwater rivers meet the ocean’s salt water Contain salt marshes with grasses and plants Animals that live here include crabs, shrimp, birds, muskrats This is the nursery for the ocean

What’s for Dinner – Food!  

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All organisms need energy to live and grow. This energy comes from food. Different organisms get their food in different ways.

We are going to make a foldable showing three different groups

Producers 

Plants are producers because they produce their own food (photosynthesis).

Consumers 

Animals cannot make their own food so they must eat plants and other animals.

3 main groups of consumers include: 

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Herbivores – animals that eat only plants Carnivores – animals that eat only animals Omnivores – animals that eat both animals and plants

Decomposers 

These are consumers that get their energy by breaking down dead or decaying matter.

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Microorganisms, termites, worms, fungi

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These organisms release nutrients back into the food chain for plants.

Food Chain  

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A series of plants and animals in which each organism is a food for the next in the chain. In a typical food chain, plants begin the chain. Interconnected food chains form a food web.

Grassland food chain 

One example of a grassland food chain:

sun

grass grasshopper toad snake hawk

Food Chain Poem Food Chain Who eats what? Who eats who? Who eats me? Who eats you? Food chain shows, What things eat, What eats plants,

Who eats meats...

Starts with sun, Producers grow, They make food, Don’t you know? Consumers come,

For energy, Eat those plants. They’re quite tasty… Food chain might,

Poem, continued Bird eats worm…

A shark will eat, Other fish, That eat seaweed, As their dish... A fox will hunt, That's not news, Eats a mouse, And rabbits too… But who eats fox? Food chain shows, A wolf? A bear? How nature goes! Food chains say, What eats who, Who eats me, And what eats you! what is a food chain? Food chains describe which organisms get their energy from which other organisms in an ecosystem. Producers, such as green plants and algae get their energy from the sun and make their own food. Consumers eat producers (such as a rabbit eating grass), but can also eat other consumers (a fox eating the rabbit). When living organisms die, they are broken down by decomposers such as fungi, and the nutrients are returned to the soil where they can support the growth of producers.

Predators and prey  

Predators – animals that hunt and kill other animals for food Prey – the animal that is being hunted and killed for food

Parasite and host 

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Parasite – an organism that spends most of its life living on or in another organism (host) usually causing harm Host – organisms or cells that serve as a home or source of food for a parasite

Limiting Factors 

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An ecosystem only has a certain amount of food, water, space and shelter available to support a certain number of organisms A condition or resource that keeps a population a certain size is the limiting factor. When limiting factors change, population may increase or decrease

Population increases  

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May result in overcrowding If there are more plants than usual, populations of animals that eat these plants may increase If the population of predators increases, the prey will decrease If the population of prey increases, the predators will increase also b/c there is more food.

Population decreases 

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If the water supply decreases, the organisms that need that water will decrease, then the animals that eat those organisms will decrease also. If organisms no longer have enough space to survive, they will have to move or will die. This can happen because of humans or natural causes.

Habitat Destruction 

The biggest reason for declining populations is habitat destruction by man.

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Building or cutting down trees impacts every organism that lives in that ecosystem.