Transcript Ecological Relationships

18/07/2015
Ecological Relationships
W Richards
The Weald School
Ecosystems
18/07/2015
“Ecosystem” is a term used to describe all of the organisms
living together as a community in a particular habitat.
Ecosystems are constantly changing:
Changes in
population due
to predation,
disease etc
Physical changes
(e.g. temperature
change)
Changes in
ecosystems
Pollution
Human
interference
Changes in soil
conditions
Taking samples of an ecosystem
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Using different “sampling techniques” we can measure changes
in an ecosystem. The two main measurements are:
1) The physical conditions of a habitat (temperature etc)
2) The populations of different species in that habitat
Some common ways of measuring…
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Measuring
temp, pH etc
Taking animal
samples
Taking samples
using quadrats
Food chains
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A food chain shows where the energy goes in a food chain (in
other words, “what gets eaten by what”):
Cabbage
Rabbit
Plants convert the
sun’s energy into food
Stoat
Fox
The arrows indicate where
the energy is going
Pyramids of number
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In this food chain we can see that the number of organisms in
each stage is less than in the previous stage:
Cabbage
Rabbit
Stoat
Fox
We can draw a “Pyramid of Numbers” to show this pattern:
One fox
A few stoats
Some rabbits
Lots of cabbages
“Funny looking” pyramids
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Consider this food chain instead:
Tree
Greenfly
Ladybird
One bird
Some ladybirds
Many greenfly
ONE tree
Bird