ecosystems learning intention to be able to describe what is meant by a habitat, population,...
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Learning Intention
• To be able to describe what is meant by a habitat, population, community and ecosystem.
Population of sea turtles
Population of dolphins
Community = all the plants and animals in a habitat
Water habitat
Learning Intention
• To be able to:– Give an example of a food chain.– Identify the producers, primary and
secondary consumers in a food chain.
What happens to the What happens to the food plants make in food plants make in
photosynthesis?photosynthesis?
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’.
• Producers - organisms which can make their own energy from carbon dioxide and water using sunlight for energy (plants)
Arrange these into food chains
1. Lion, grass, Zebra2. Weasel, fieldmouse, owl, wheat3. Greenfly, oak leaf, thrush, ladybird4. Herring, animal plankton, human,
plant plankton5. Frog, hawk, grass, snake,
grasshopper
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.
Questions1. What is the source of energy entering a food
chain?
2. What does every food chain begin with?
3. Name two ways in which energy can be lost in a food chain.
3 things• Write down 3 things you know now
that you didn’t know at the start of the lesson.
• Once you have both finished, share them with the person beside you.
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
Food Webs
Herb Live oak leaf Dead oak leaf
Greenfly Moth caterpillar
Earthworm Soil fungi
Ladybird Spider Vole
Small bird Owl The Food Web shown is from a typical woodland community.
Carnivores
Herbivores
Decomposers
Producers
Constructing a food webConsumer Food
Rabbit Oak, Primrose
Vole Primrose
Snail primrose
Frog snail
Weasel Vole, rabbit
Owl Vole
Hedgehog Snail, vole
Fox Frog, hedgehog, rabbit, weasel
Learning Intention
• Explain relationships between different organisms in a food web and effects of removing a species.
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.
Great White Shark
Clown Fish Sea Turtle
Algae
Blue Regal
Zooplankton
Small Invertebrates
Food Web
Learning Intention
• To be able to arrange organisms from a food chain into pyramids of number and biomass.
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?)
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.
PYRAMID OF NUMBERS• Shows population size at each
stage in a food chain
1 HAWK
10FROGS
100CRICKETS
1000GRASS PLANTS
Choose one of the pyramids of numbers above to represent each of the three food chains below.
DANDELIONS RABBITS FOX FLEAS
PEAR TREE APHIDS LADYBIRDS PARTRIDGE
GREEN PLANTS SLUGS FROG FOX
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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