1. Ecology-Matter & Energy Cycling

2. Ecology What is ecology?
The study of organisms and how they interact with each other and their environment
A relatively new field of science

3. Ecology
Nutrients cycle through living and nonliving components in the ecosystem
The sun and gravity drive the cycling of all nutrients on earth
Life on earth depends on the flow of energy (sun) through the environment

4. Ecology Three important cycles are The carbon-oxygen cycle
The water cycle
The nitrogen cycle

5. The Carbon-Oxygen Cycle
Why is the C-O cycle needed?
Carbon and oxygen are required to make glucose, the energy source for all cells
Energy from the sun is stored in carbohydrates

6. The Carbon-Oxygen Cycle
Carbon dioxide cycles through autotrophs
It is converted into sugar (photosynthesis)
Oxygen is given off in the process
CO2 is released as the sugar is broken down by heterotrophs and autotrophs
cellular respiration
Oxygen is consumed to enable the electron transport chain
Energy +6CO2 + 6H2O C6H12O6 +602

7. The Carbon-Oxygen Cycle
How do humans intervene with the cycle?
Burning fossil fuels also adds to the CO2 in the atmosphere, as well as other pollutants
Removing large numbers of trees and forested areas

8. The Water Cycle Why do we need the H2O cycle?
Water is needed for all cell processes
Every cell consists of about 80% water
You can live for a few weeks without food, but only a few days without water!

9. The Water Cycle
Water evaporates from the surface or from plant leaves (transpiration)
As the vapor cools and condenses, clouds form
When the droplets get heavy, they fall (precipitation)

10. The Water Cycle Water can then: Runoff on the surface of the land
Infiltrate into the top layers of soil
Percolate into deep underground reservoirs
Water eventually runs back to the ocean to cycle again

11. The Water Cycle How do humans intervene?
Drawing huge amounts of groundwater
Paving streets and walkways
Cutting forests

12. The Nitrogen Cycle Why do we need the N cycle?
Nitrogen is needed in amino acids-the building block of proteins
All cell structures contain protein

13. The Nitrogen Cycle
Nitrogen in the gas form is not useable by green plants
Bacteria (N-fixers) put the nitrogen into water-soluble molecules in the soil
Other bacteria break down dead organisms and animal waste to release nitrogen compounds

14. The Nitrogen Cycle
Plants take up the nitrogen compounds with their roots
They make amino acids and eventually plant proteins
Animals eat plants and use the amino acids to make animal proteins

15. The Nitrogen Cycle How do humans intervene in the N Cycle?
Nitrogen is mined for fertilizers
Fossil fuels release nitrous oxides into the atmosphere

16. Food Chains and Webs
Food chains are simple diagrams of the feeding sequence of an ecosystem

17. Food Chains and Webs
Food chains are simple diagrams of the feeding sequence of an ecosystem
They show organisms feeding on one thing at one trophic level

18. Food Webs
Most animals feed on different things and at different trophic levels, forming a web.
Food webs represent several interconnected chains

19. Energy Pyramids
Energy pyramids illustrate that as energy moves up through the trophic levels, energy is “lost”
The energy does not disappear, but changes into unusable forms (heat, metabolism, indigestible fiber, etc)
About 90% of the food energy is not passed to the next level.

20. Energy Pyramids
There are fewer consumers at the upper levels due to the amount of energy available
Aquatic ecosystems have more trophic levels than terrestrial ecosystems
There are many microscopic levels in the food web