Cycling of Matter

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??

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

What Sustains Life on Earth?

Solar energy

The cycling of matter

Gravity

Nutrients are recycled, energy is not (enters as sunlight, leaves as heat)

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 nutrientsAnimals obtain C, H, O, N they need from

eating

Plants absorb CO2 from air, H2O & nitrates from soil

Nutrient Cycles Nutrient Cycle: the process of moving a

nutrient back & forth between biotic and abiotic parts of ecosystemsCan occur quickly or remain in one place for

a long time

Reservoir: any place where matter builds up

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

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

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

Homework – Water Cycle

1. What are 2 processes that cause water to enter the atmosphere?

2. Give an example of how water moves from the biotic to the abiotic part of an ecosystem.

3. How is the cycling of nutrients different from the movement of energy in an ecosystem?

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

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

Homework - Nitrogen Cycle

1. What types of bacteria are involved in the nitrogen cycle, and what does each do?

2. What would happen to nutrient cycling if an unknown disease were to kill all the bacteria/fungi in an ecosystem?

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…

Photosynthesis The Sun’s energy is captured by

chlorophyll in plants and converted into chemical energy, which can be stored as sugar

PhotosynthesisCO2(g) + H2O + Sunlight Glucose + O2(g)

UsedProduced

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

Homework - Carbon Cycle

1. List 1 abiotic & 1 biotic carbon reservoir.

2. What is the role of photosynthesis in the ecosystem?

3. How are photosynthesis and cellular respiration related?

4. Why do plants need cellular respiration?

https://www.youtube.com/watch?v=2D7hZpIYlCA https://www.youtube.com/watch?v=leHy-Y_8nRs