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8D Ecological relationships
8D Ecological
relationships
Classification
What lives here?
Energy flow
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8D Ecological relationships
Classification
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8D What’s that?
Biology is full of long words.
Do you know what the words vertebrate and
invertebrate mean?
Are these vertebrates or invertebrates?
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8D The animal kingdom
Which group do you think that these belong to?
crab
sea urchin
frog
penguin
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8D Sowing the seeds…
Plants are often classified according to how they
reproduce.
Which of these do you think produce seeds?
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8D The plant kingdom
What group do these belong to?
dicotyledon
conifer
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fern
Trick! A lichen is a
fungus and an
alga growing
together, not a
plant.
8D Ecological relationships
What lives here?
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8D What lives here?
To describe the living things in an area you need to know:
What lives there (the biological names) and
how many of each type of organism are present.
You use a key to find the names. How do you find the
number of organisms?
How many plants in
this pot?
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How many bluebells in
this wood?
8D Quadrats
Instead of counting the bluebells, biologists count
samples.
To do this they use a frame called a quadrat. They can
put it on the ground to show exactly one square metre.
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8D Quadrats
A quadrat measures one metre by one metre.
There were 30 bluebell plants in my quadrat.
The woodland area with bluebells covers 3,245 square
metres.
So, how many bluebells in the whole wood?
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8D Sample data
Sample
Bluebells present
1
2
3
23
10
27
4
32
The total woodland area is 3,245 square metres.
How many bluebells if you only used data from sample 1?
How many bluebells if you only used data from sample 2?
How many bluebells if you average the data from all the
samples?
Should you ignore sample 2?
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8D Rules for collecting data
Take small samples and multiply up your results.
Collect more than one sample if you can.
Share the work with others.
Take your samples randomly – this means that you may
have some surprises in the data.
If you are working with other people make sure that they
are collecting data in the same way.
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8D Ecological relationships
Energy flow
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8D Food for all
What is the name of the reaction that produces food on
which all life depends?
The food is produced by the green plants.
Some animals eat the plants. What are they called?
Some animals eat other animals. What are they called?
Everything depends on the plants because only they can
make food by...
Photosynthesis
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8D A few words to check
Can you match each word to its definition?
Carnivores
Animals that only
eat plants
eat animals.
and animals.
Consumers
Organisms that cannot
build food
make
using
food
energy
by photosynthesis.
from sunlight.
Producers
Organisms
Animals thatthat
only
build
eat food
plants.
using energy from sunlight.
Herbivores
Animals
Organisms
thatthat
only
cannot
eat plants.
make food by photosynthesis.
Omnivores
Animals that eat
onlyplants
eat animals.
and animals.
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8D Revising chains and webs
A researcher wants to show that a rabbit eats grass.
Which is correct?
rabbit
grass
grass
rabbit
rabbit
grass
The arrow always points to the organism that does
the eating.
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8D Webs and numbers of organisms
A farmer clears the blackberry plants to make way for
a field of grass.
What happens to the greenfly population?
What happens to the vole population? Why?
What happens to the rabbit population? Why?
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8D Webs and numbers of organisms
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8D Webs and total numbers
Sometimes biologists try to simplify food webs by sorting
all the organisms into levels depending on the food they
eat.
The primary producers are level 1.
All the animals that eat them are called primary
consumers. They are level 2.
The animals that eat primary consumers are called
secondary consumers. They are level 3.
The animals that eat secondary consumers are
called tertiary or third consumers. They are level 4.
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8D Pyramids of numbers
In this food web there is lots of grass. The wide bar
shows this.
Lots of animals live on the grass. But there are fewer
hares than grass plants so the bar is narrower.
It takes quite a lot of hares to
feed one eagle so the third
layer up is even narrower.
eagle
hare
grass
What levels are the grass, the hares, and eagles?
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8D Strange pyramids!
Here’s a strange pyramid! How does it work?
This layer includes the birds and
animals that eat the insects. Now
we’re back to sensible pyramids!
This layer includes all the
leaf-eating insects like
caterpillars. A single oak
tree can have millions of
these!
This layer is a large old oak tree. It’s
huge but there’s only one so the bar is
very narrow.
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blackbird
caterpillar
oak tree
8D Pyramids of biomass
Another way to look at pyramids is to measure the
weight of living materials at each level.
The biomass pyramids work well for grassland.
They also make sense of our strange oak tree
pyramid. Why?
eagle
blackbird
caterpillar
hare
grass
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oak tree
8D Explaining pyramids
The primary producers can capture lots of energy from the Sun. They
grow and reproduce very well to make a large population.
When a rabbit eats grass some of the energy is lost. This passes out
in faeces or is used just keeping the rabbit alive.
The same is true for the foxes that eat the rabbits, so the next layer up
has even fewer animals.
Pyramids of numbers make sense because of the energy lost between
levels.
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8D Testing ecology
1. Carnivore means…
a) an animal that eats meat
b) an animal that is eaten by another animal
c) an animal that eats plants.
2. Prey animals often have camouflage to…
a) hide from predators
b) attract a mate
c) keep them warm at night.
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