INTERDEPENDENCE of LIVING ORGANISMS 1 © Hans pfletschinger

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) 2

A food chain (1) The caterpillar eats the leaf…. (2)....the blue tit eats the caterpillar... (3)....the kestrel eats the blue tit. This is an example of a food chain

Animals depend on plants for food The food chain Cabbage Snail Thrush Sparrow hawk 4

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 5

fox owl stoat rabbit rat beetle 6

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. 7

All organisms depend on sunlight SUNLIGHT Wheat grains Flour Bread Cow Milk Cheese Nectar Bees Honey Photosynthesis in wheat Photosynthesis in grass Photosynthesis in flowering plants 8

Pyramid of numbers Example of a food pyramid The width of each band represents the number of organisms Plant leaves Caterpillars Blue tits Owl 9

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 10

Atmospheric carbon dioxide Production of carbon dioxide Uptake of carbon dioxide Burning of fuel: wood, coal, oil and gas. Respiration in all organisms Decay of organic matter Photosynthesis in plants Absorption by the oceans 11

12 The carbon cycle

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 13

Recycling and the role of decomposers PRODUCERS green plants CONSUMERS animals DECOMPOSERS bacteria and fungi SOIL minerals and humus sunlight 14

Decomposers If it were not for bacterial and fungal decomposition, we would be knee deep in dead leaves after a few years 15

Conclusion The inter-relationships between all living organisms are so complex that any disturbance in the patterns of interdependence can have far- reaching consequences 16

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 CO 2

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