1. Ch 5. How Ecosystems Work Section 1- Energy flow in ecosystems

2. How Ecosystems Work
Photosynthesis- plant using sunlight to make sugar molecules or carbohydrates
Photosynthesis 6CO2 + 6H20 + solar energy = C6H12O6 + 6O2
Ex. Plants, Algae, some Bacteria

3. How Ecosystems Work
Autotroph (producer) - producer own food or self-feeder
Heterotroph (consumer)- get energy from eating other organisms
Ex. Plants, Algae, some Bacteria
Mice, elephants, humans, ants

4. How Ecosystems Work Herbivore Carnivore Omnivore Decomposers Cows Lion
Humans
Bacteria, fungi

5. How Ecosystems Work
Cellular Respiration- process of breaking down food to yield energy
NOT the same as respiration which is another name for breathing
Formula for cellular respiration
C6H12O6 + 6O2 = 6CO2 +6H2O + energy

6. How Ecosystems Work
Food chain- energy is transferred from one organism to the next as each organism eats another
Food web- shows many feeding relationships that are possible
Trophic level- each step through which energy is transferred
At each level we lose energy as heat , cellular respiration, produce new cells, regulate heat, moving

7. Food chain

8. Food web

9. Energy Pyramid

10. How Ecosystems Work
What is the difference between a food web and a food chain?
Why are there not five and six trophic levels in ecosystems?
What is biomagnification

11. How Ecosystems Work
Biomagnification- increase in concentration of a substance, such as the pesticide DDT, that occurs in a food chain because of persistence (slow to be broken down by environmental processes)
Other examples are Arsenic, Lead, PCB’s, and Mercury

12. How Ecosystems Work Section 5.2 The Cycling of Materials
Carbon Cycle- Process by which C is cycled between land, water, and organisms
Limestone is one of the largest carbon sinks (carbon reservoirs) on Earth
EX. Consumers eat producers and obtain carbon, then consumers break down the food during cellular respiration, which releases carbon as carbon dioxide

13. How can driving a car affect the Carbon cycle?
Burning of fossil fuels releasing CO2
Cars, factories, power plants, forest fires
Increased levels of CO2 contribute to global warming.
Approximately, over 1 billion tons of CO2 dissolves into the ocean (ex. Of a carbon sink)
Plants are also carbon sinks-natural or manmade reservoir that accumulates and stores carbon.

14. Affects of burning fossil fuels?

15. Carbon cycle

16. The Nitrogen cycle
Process by which N is cycled through land, water, and organisms
Nitrogen is essential to build proteins – which are necessary to build new cells
N makes up 78% of gases in the atmosphere
Most organisms cannot use atmospheric N except Nitrogen-fixing bacteria. These grow as nodules on the roots of plants.
Legumes contain these bacteria to produce N for plants .. Ex. Soybeans, clover

17. The Nitrogen cycle

18. The Nitrogen cycle Decomposers have a crucial role in the N cycle.
These organisms break down organic matter including fecal matter, leaves, decaying plants and animals to return N to the soil.
Ex. Dung Beatle

19. The Phosphorous cycle
Movement of P from the environment to organisms and then back to the environment.
Slow cycle and usually does NOT include the atmosphere because P is rarely a gas.
11th most abundant element in the Earth’s crust.
Plants absorb P in the root system.
Many of the phosphate salts are not soluble in water and end up at the bottom of the ocean and accumulate as sediment.

20. The Phosphorous cycle

21. Section 5.3 How Ecosystems Change
Ecological succession is a gradual process of change and replacement of species in a community
Ecological succession is divided into both primary and secondary succession
Primary occurs when there has been no previous ecosystem such as new volcanic islands
Secondary succession occurs when there has been a previous ecosystem such as a reestablishment after a forest fire, floods, and earthquakes

22. Section 5.3 How Ecosystems Change

23. Section 5.3 How Ecosystems Change

24. Section 5.3 How Ecosystems Change
Pioneer species- first organisms to colonize a newly available area and begin ecological succession
Climax community is the final and stable stage of a community with very little change.
Ex. Lichens, algae

25. Section 5.3 How Ecosystems Change
Old-field succession- occurs when old farmland is abandoned and succession takes place– secondary succession
What is an example of secondary succession in a city?
Plants growing through pavement

26. Ch 5 summary
Majority of Earth’s organisms depend on the sun for energy. Which do not?
The paths of energy transfer can be followed through food chains, food webs, and trophic levels
Approximately 10% of energy an organism consumes is transferred to the next trophic level.
Materials in ecosystems are recycled or resused by natural processes such as the N, P, C cycles.
The human affect on the cycling of materials in an ecosystem through activities such as burning fossil fuels and fertilizer applicaiton.

27. Ch 5 summary
After a disturbance organisms in an environment follow a pattern of change over time, known as succession.
Primary succession occurs on a surface where no ecosystem occurred before.
Secondary succession occurs where an ecosystem has existed
Climax communities are made up of organisms that take over an ecosystem and remain until the ecosystem is disturbed again.

28. Class Assignment
Complete the two critical thinking questions on page 129. You must read the article first, then answer the questions.