1. Cycling of Matter

2. Warm Up Difference between abiotic & biotic factors
Abiotic factors affecting oak tree growth
Southern ON  Arctic - vegetation change
Stream is an aquatic ecosystem, but also part of a forest ecosystem??

3. Learning Goals
Understand that nutrients move through ecosystems in cycles
Describe the processes by which water, nitrogen and carbon are moved through ecosystems
Describe the relationship between photosynthesis and cellular respiration

4. What Sustains Life on Earth?
Solar energy
The cycling of matter
Gravity
Nutrients are recycled, energy is not (enters as sunlight, leaves as heat)
Nutrients are recycled (Lion King reference – “we eat the antelope…”
Energy is not recycled -

5. Nutrient Cycles
Nutrients in food provide energy & matter needed to stay alive  carbohydrates, fats, proteins, vitamins, minerals
Elements: pure substances that cannot be broken down into simpler substances that make up nutrients
Animals obtain C, H, O, N they need from eating
Plants absorb CO2 from air, H2O & nitrates from soil

6. Nutrient Cycles
Nutrient Cycle: the process of moving a nutrient back & forth between biotic and abiotic parts of ecosystems
Can occur quickly or remain in one place for a long time
Reservoir: any place where matter builds up
CO2 exhaled by wildebeest – C in atmosphere; CO2 absorbed by plant, becomes part of a carbohydrate in plant cells
Glaciers – water 1000s of years old

7. Water Cycle
1. Sun’s heat warms surface H2O which evaporates into atmosphere
2. In atmosphere  exists as water vapour
3. Water vapour cools, condensing into clouds  falls as precipitation

8. Water Cycle 4. Hits ground, runs off into streams/rivers (“run off”)
5. Some seeps through soil into ground water  may flow into large underground lakes (“aquifers”) or wetlands or oceans

9. Water Cycle
6. Some H2O on the surface or in the soil is taken up by animals or plants (“root uptake”)
7. Plants release water vapour into the atmosphere through their leaves (“transpiration”)
8. Water vapour rises into the atmosphere, continuing the cycle

10. Homework – Water Cycle
What are 2 processes that cause water to enter the atmosphere?
Give an example of how water moves from the biotic to the abiotic part of an ecosystem.
How is the cycling of nutrients different from the movement of energy in an ecosystem?

11. Nitrogen Cycle Organisms need N to make proteins
The atmosphere is 78% N but it must be converted into ammonia via nitrogen fixation to be useful
Nitrogen-fixing bacteria found in root nodules of legume plants (beans, peas) as well as in soil and water do this

12. Nitrogen Cycle
Nitrifying bacteria then convert ammonia into nitrites and then nitrates, which plants can absorb
Animals get N from eating plants or other animals  a waste product of protein digestion is ammonia
Bacteria & fungi in soil break down ammonia in waste & dead organisms into nitrates/nitrites
Released back into soil to be absorbed by plants
Denitrifying bacteria in soil convert nitrates back to N(g) to return N to the atmosphere

14. Homework - Nitrogen Cycle
What types of bacteria are involved in the nitrogen cycle, and what does each do?
What would happen to nutrient cycling if an unknown disease were to kill all the bacteria/fungi in an ecosystem?

15. Carbon Cycle
The atmosphere is 0.04% CO2  all the C plants need comes from this
Biotic reservoir = world’s forests
Abiotic reservoirs = fossil fuels (underground coal, oil, natural gas); oceans (dissolved CO2 used by marine organisms to build tissue)
Photosynthesis & cellular respiration move carbon between these reservoirs…

16. Photosynthesis
The Sun’s energy is captured by chlorophyll in plants and converted into chemical energy, which can be stored as sugar

17. Photosynthesis
CO2(g) + H2O + Sunlight  Glucose + O2(g) Used Produced

18. Cellular Respiration
Plants store energy in the form of glucose (sugar) which they make from sunlight
Cellular respiration: process where glucose is combined with O2(g) to form CO2(g) and H2O, and to release energy for use by an organism’s cells
Both plants and animals carry out C.R., but animals must obtain glucose from foods they eat
glucose + O2(g)  CO2(g) + H2O + energy

20. Homework - Carbon Cycle
List 1 abiotic & 1 biotic carbon reservoir.
What is the role of photosynthesis in the ecosystem?
How are photosynthesis and cellular respiration related?
Why do plants need cellular respiration?