1. Food Webs and Pyramids
Biology

2. Some definitions… Autotroph Heterotroph Herbivore Carnivore Omnivore
Decomposer

3. Food chains

4. Food Webs

6. The Flow of Energy
Producers - Plants capture the sun’s energy and store it in food
Primary Consumers (herbivores) - Animals that receive their energy directly from plants
Secondary Consumers (carnivores) - Consumers that feed on primary consumers
Energy flow:
Sun  producers  primary consumer  secondary consumer  third level consumer  etc…

8. Ecological Pyramids
Biomass - the amount of living biological material in an ecosystem

9. Energy Pyramid
Only 10% of energy is available to next level

10. 10% Rule of Energy Transfer
33%
50%
and waste
17%

11. Biomass Pyramid

12. Pyramid of Numbers

13. Better to eat corn or meat??

14. Let’s Practice
Determine the amount of useable energy for the different trophic levels.

15. Biological Magnification

16. Biological Magnification

17. OBJ 7
Invasive Species

18. OBJ 7
Invasive species

19. Frontier of rabbit spread 1860
Figure 37.13A
600 km
1980
1910
1910
1900
1910
1920
1920
1910
1890
1900
Figure 37.13A The spread of rabbits in Australia
1910
1880
1920
1920
1890
1870
1880
Key
1870
Frontier of rabbit spread
1860 19

20. Figure 37.13B
Figure 37.13B A familiar sight in early 20th-century Australia 20

21. Figure 37.13C
Figure 37.13C A cane toad (Bufo marinus) 21