2. LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END COMPUTER PRESENTATIONS FOR KS3 SCIENCE - BIOLOGY ©2003, STEVE PARKER COMPUTER PRESENTATIONS FOR KS3 SCIENCE - BIOLOGY ©2003, STEVE PARKER

3. 1 1 KS3 SCIENCE - BIOLOGY KS3 SCIENCE - BIOLOGY Food Chains

4. FOOD CHAINS & WEBS 2 2

5. 3 3 A Food Chain shows which creatures eat each other A Food Chain shows which creatures eat each other In this example, grass is eaten by cows, which are eaten by people In this example, grass is eaten by cows, which are eaten by people

6. FOOD CHAINS & WEBS 4 4 Plants that produce food energy using the Sun are called Producers Plants that produce food energy using the Sun are called Producers Producer

7. FOOD CHAINS & WEBS 5 5 Animals that eat producers are called Consumers Animals that eat producers are called Consumers Producer Primary Consumer Primary Consumer Secondary Consumer Secondary Consumer

8. FOOD CHAINS & WEBS 6 6 Producers are either green plants or plant plankton Producers are either green plants or plant plankton

9. FOOD CHAINS & WEBS 7 7 Primary consumers are Herbivores - they eat plants Primary consumers are Herbivores - they eat plants

10. FOOD CHAINS & WEBS 8 8 Secondary consumers are Carnivores - they eat animals Secondary consumers are Carnivores - they eat animals There are also Tertiary consumers who eat secondary consumers There are also Tertiary consumers who eat secondary consumers

11. FOOD CHAINS & WEBS 9 9 A Food Web is a more complex picture of linked food chains A Food Web is a more complex picture of linked food chains

12. FOOD CHAINS & WEBS 10 Pesticide Pesticide passes up the food chain and is not broken down in the body, so it becomes more and more concentrated Pesticide passes up the food chain and is not broken down in the body, so it becomes more and more concentrated

13. NUMBER PYRAMIDS 11

14. NUMBER PYRAMIDS 12 LADYBIRDS ROSELEAVES Number pyramids tell us the population at each Trophic Level Number pyramids tell us the population at each Trophic Level APHIDS

15. NUMBER PYRAMIDS 13 LADYBIRDS ROSELEAVES Number pyramids tell us the population at each Trophic Level Number pyramids tell us the population at each Trophic Level APHIDS LEVELS 3rd 2nd 1st LEVELS 3rd 2nd 1st NUMBER 10 100 1000 NUMBER 10 100 1000

16. NUMBER PYRAMIDS 14 Number pyramids may not always be pyramid shaped Number pyramids may not always be pyramid shaped TREE CATERPILLARS BIRDS

17. NUMBER PYRAMIDS 15 There are also pyramids of Biomass, measuring total mass at each level There are also pyramids of Biomass, measuring total mass at each level TREE CATERPILLARS BIRDS

18. FOOD ENERGY 16

19. FOOD ENERGY 17 At each stage when food energy is consumed, much of it is lost by the creature At each stage when food energy is consumed, much of it is lost by the creature

20. FOOD ENERGY 18 100 units of energy Ingested 100 units of energy Ingested 63 units are lost in urine & faeces 63 units are lost in urine & faeces 33 units used up by breathing & heat loss 33 units used up by breathing & heat loss

21. FOOD ENERGY 19 100 units of energy Ingested 100 units of energy Ingested Only 4 units are used for growth and are available for consumers eating cows at the next trophic level Only 4 units are used for growth and are available for consumers eating cows at the next trophic level

22. FOOD ENERGY 20 Only 4 units are used for growth and are available for consumers eating cows at the next trophic level Only 4 units are used for growth and are available for consumers eating cows at the next trophic level As there is less energy further up the food chain, there are fewer Top Carnivores As there is less energy further up the food chain, there are fewer Top Carnivores