INTERDEPENDENCE of LIVING ORGANISMS 1 © Hans pfletschinger

INTERDEPENDENCE of
LIVING ORGANISMS
© Hans pfletschinger
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The picture shows a bee visiting a sage flower
It provides an example of interdependence
The bee is dependent on the flower for its nectar
The flower is dependent on the bee for pollination
(You will need to have an understanding of respiration
and photosynthesis to follow this slide show)
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A food chain
(3)....the kestrel eats the
blue tit.
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(2)....the blue tit eats the
caterpillar...
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(1) The caterpillar eats
the leaf….
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This is an example of
a food chain
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Animals depend on plants for food
The food chain
Sparrow hawk
Thrush
Snail
Cabbage
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The sparrow hawk does not depend directly on plants
but it does depend on thrushes, which eat snails, which
eat cabbages.
So the sparrow hawk is indirectly dependent on plants
Food chains are never so simple as the ones in slides
3 and 4
Sparrow hawks do not feed exclusively on thrushes;
thrushes eat worms as well as snails; snails eat many
plants, not just cabbages
A more accurate picture is given by a food web
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owl
fox
stoat
rat
beetle
rabbit
Question
What is the most likely outcome of a severe fall in the
numbers of foxes?
(a) Increase in rabbits, decrease in rats, increase
in owls
(b) Increase in rabbits,increase in stoats, increase
in vegetation
(c) Decrease in rabbits, increase in beetles, increase
in vegetation
(d) Increase in rabbits, increase in owls, decrease in
vegetation.
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All organisms depend on sunlight
SUNLIGHT
Photosynthesis
in wheat
Wheat grains
Photosynthesis
in grass
Photosynthesis in
flowering plants
Cow
Nectar
Flour
Milk
Bees
Bread
Cheese
Honey
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Pyramid of numbers
Owl
Blue tits
Caterpillars
Plant leaves
Example of a food pyramid
The width of each band represents the
number of organisms
Dependence on oxygen and carbon
dioxide
Animals need oxygen for respiration
Plants produce oxygen in photosynthesis
Animals produce carbon dioxide in respiration
Plants use up carbon dioxide in photosynthesis
The process of decay uses up oxygen and
produces carbon dioxide
This interdependence is represented by the
Carbon Cycle
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Atmospheric carbon dioxide
Production of carbon
dioxide
Uptake of carbon
dioxide
Burning of fuel: wood,
coal, oil and gas.
Photosynthesis in
plants
Respiration in all
organisms
Decay of organic
matter
Absorption by the
oceans
The carbon cycle
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Dependence on bacteria
Most bacteria are beneficial
They break down dead organisms into simpler
substances
Soil bacteria make mineral salts available
to plants
Bacteria and fungi are called decomposers
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Recycling and the role of decomposers
SOIL
minerals and
humus
DECOMPOSERS
bacteria and fungi
sunlight
PRODUCERS
green plants
CONSUMERS
animals
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Decomposers
• If it were not for bacterial and fungal decomposition, we
would be knee deep in dead leaves after a few years
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Conclusion
The inter-relationships between all
living organisms are so complex that
any disturbance in the patterns of
interdependence can have farreaching consequences
Question 1
Which of the following might be genuine food chains?
(a) zebra - lion - giraffe - leopard - antelope
(b) grass - grasshopper - lizard - snake - eagle
(c) aquatic vegetation - hippopotamus - tick oxpecker bird - tawny eagle
(d) stickleback - pondweed - minnow - pike kingfisher
Question 2
Which of these organisms might be classed as ‘producers’?
(a) mosses
(b) fungi
(c) trees
(d) earthworms
Question 3
Which of these statements is most accurate?
In bright sunlight a green plant will be...
(a) photosynthesising only
(b) respiring only
(c) photosynthesising and respiring
(d) taking in oxygen and giving out CO2
Question 4
Which of these increase the concentration of carbon dioxide
in the atmosphere?
(a) respiration
(b) photosynthesis
(c) combustion
(d) decay
ANSWER
Incorrect
ANSWER
Correct