Ecosystems

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Ecosystems
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Learning Intention

• To be able to describe what is meant by a
  habitat, population, community and ecosystem.

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Habitat

• An organisms habitat is the place where it lives.

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Population

• A population is all the members of one species in
  an ecosystem.

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Population of sea turtles
Population of dolphins
Water habitat
Community all the plants and animals in a
habitat
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Example of an ecosystem
Ecosystem Community Habitat
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Learning Intention

• To be able to
• Give an example of a food chain.
• Identify the producers, primary and secondary
  consumers in a food chain.

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What is a food chain?
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Photosynthesis.........
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What happens to the

• food plants make in photosynthesis?

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Food Chains

• Food chains show which organisms eat other
  organisms
• Grass Rabbit Fox
• The arrows show the transfer of energy from one
  organism to the next.
• It also helps to think of the arrows as meaning
  is eaten by.

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• Producers - organisms which can make their own
  energy from carbon dioxide and water using
  sunlight for energy (plants)

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Primary consumer - organisms which eat producers.
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• Secondary consumers - organisms which eat primary
  consumers.

Secondary consumers are predators
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Arrange these into food chains

1. Lion, grass, Zebra
2. Weasel, fieldmouse, owl, wheat
3. Greenfly, oak leaf, thrush, ladybird
4. Herring, animal plankton, human, plant plankton
5. Frog, hawk, grass, snake, grasshopper

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Learning Intention

• To be able to describe the path of energy flow in
  a food chain.

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Energy loss

• Some energy is lost at each stage in a food
  chain.
• Each organism in a food chain uses some of the
  energy to build up its body and grow.
• Most of the energy that organisms gain in a food
  chain is used up when the organism moves about,
  and in warm-blooded animals, to keep warm.
• This means that, as humans, it is more efficient
  for us, and we receive more energy from, eating
  plants.

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Questions

• What is the source of energy entering a food
  chain?
• What does every food chain begin with?
• Name two ways in which energy can be lost in a
  food chain.

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3 things

• Write down 3 things you know now that you didnt
  know at the start of the lesson.
• Once you have both finished, share them with the
  person beside you.

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Learning Intention

• To be able to give an example of a food web.

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What is a food web?

• A food web is made up of 2 or more food chains
  joined together.
• For example -
• Grass Rabbit Fox
• Grass Caterpillar Bird
• Grass Beetle Mouse Fox

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Would make this food web
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More complex food webs
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Food Webs
The Food Web shown is from a typical woodland
community.
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Constructing a food web
Consumer Food
Rabbit Oak, Primrose
Vole Primrose
Snail primrose
Frog snail
Weasel Vole, rabbit
Owl Vole
Hedgehog Snail, vole
Fox Frog, hedgehog, rabbit, weasel
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Learning Intention

• Explain relationships between different organisms
  in a food web and effects of removing a species.

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• Questions
• 1. What will happen to the number of clown fish
  if the sharks become vegetarian?
• 2. What effect will this have on the number of
  zooplankton?
• 3. What will happen to the Blue Regal fish if a
  disease wipes out the small invertebrates.

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Learning Intention

• To be able to arrange organisms from a food chain
  into pyramids of number and biomass.

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FOOD CHAIN

• GRASS CRICKET FROG HAWK

1000 GRASS 100 CRICKETS! 10 FROGS! 1!
PLANTS!
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Discussion

• What do you notice about the size of the actual
  organisms as you move along a food chain?
• What do you notice about the number of organisms
  at each stage as you move along a food chain?
• Why do you think the number of organisms at each
  stage is changing?
• (Do big organisms eat the same amount as small
  organisms?)

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Pyramids of Number

• The relationship takes the form of a pyramid
  because
• The energy loss at each link in the food chain
  limits the quantity of living matter that can be
  supported at the next level.

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PYRAMID OF NUMBERS

• Shows population size at each stage in a food
  chain

1 HAWK 10 FROGS 100 CRICKETS 1000 GRASS
PLANTS
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PROBLEM!!!!!
Can you explain the shape of this pyramid of
numbers???
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Choose one of the pyramids of numbers above to
represent each of the three food chains
below.DANDELIONS RABBITS FOX
FLEASPEAR TREE APHIDS LADYBIRDS
PARTRIDGEGREEN PLANTS SLUGS FROG
FOX
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Pyramids of biomass

• The biomass of a population is the total mass of
  living things.
• In a food chain the biomass of the producer is
  greater than the biomass of the primary consumer,
  which in turn is greater than that of the
  secondary consumer.
• Since biomass decreases at each level, it can
  also be represented as a pyramid shape.

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Pyramid of Biomass
The pyramid of biomass shows the biomass of a
population in an ecosystem.
E.g. Oak tree Insects
Birds
Birds
Insects
Oak tree
A pyramid of biomass is always a true pyramid
shape.