2. Pyramid Of Numbers GRASS RABBIT FOX Number decreases Size increases

3. The Pyramid of Biomass A pyramid of biomass shows the total biomass at each stage of a food chain. Biomass is the mass of all the organisms in that population. Biomass goes down as you move along a food chain, so this gives a pyramid shape.

5. HOMEWORK Set Tues 28 August Due Fri 31 Aug Biosphere Booklet Questions 1 - 17

6. Population The number of organisms of the same species present in an ecosystem

7. What does the growth rate of a population depend on ? Birth rate is measured by counting the number of live births in a population during an interval of time Death rate is measured by the counting the number of deaths in a population during an interval of time The growth rate of a population depends on the birth and death rates.

8. Population Growth Left unchecked a population will grow Exponentially! This is called a …… Population Explosion

9. Human Population Growth The Human Race is undergoing a Population Explosion.

10. The growth curve of a population in ideal conditions continues to rise indefinitely because the birth rate is high and the death rate is low.

11. Factors Limiting Population Growth Limiting Factors Disease/ParasitesPredators StarvationAbundance of Food Predation Lack of Space Natural Disasters

12. Competition

13. Plants compete for … Light Water Nutrients Animals compete for … Food Water Shelter Nesting Sites Mates

14. Transparent Lid Damp Cotton Wool Radish Seeds Only Cress Seeds Only Radish and Cress Seeds After 5 Days at 24 0 C Healthy Radish Healthy Cress Healthy Radish Sickly Cress

15. If the competing individuals are of the same species their needs will be almost identical so the competition will be even more intense ! This results in the stronger more successful competitors surviving and the weaker competitors dying off.

16. The Nitrogen Cycle !

17. Nitrogen Gas Nitrogen in Soil Nitrates Nitrogen in Plants Nitrogen in Animals Death and Decay Nitrogen in Ammonium Compounds Nitrogen in Nitrites in Soil Denitrification by Bacteria Lightening!

18. NItRATES Lightening Fertiliser Nitrogen Fixing Bacteria Leaching Cropping Denitrifying Bacteria Keeping It Balanced!

19. Nitrogen Cycle Questions Nitrogen Cycle Questions 1.How much nitrogen gas is there in the air? (1) 2.How can nitrogen be removed from the air? (3) 3.How can nitrogen be added to the air? (1) 4.How can nitrogen be added to the soil? (4) 5.What happens to the nitrogen in the soil? (2) 6.What happens to the nitrogen in plant proteins? (2) 7.How does decay of organisms and their wastes add nitrogen to the soil? (3) ANSWER IN FULL SENTENCES