Agenda 09/28/00 to 09/29/00
- Ecosystems – Habitats (Nutrient Cycles)
- H2O Cycle
- Carbon Cycle
- Nitrogen Cycle
- Phosphate Cycle
- Homework
- Read and Outline pgs. 349-354
- Answer pg 354: Questions 1, 3, 4
Homework review:
1) The producers, plants, are the only group that can convert energy (e.g. sunlight) into a useable form (e.g. building materials such as starch).
2) The food web would have all herbivores eating all plants, and all carnivores eating all animals. This is inaccurate, because the beetle probably does not eat the turtle. They did not say what predator ate which prey.
4) Every trophic level falls to the decomposers. They take care of anything that dies, the remains of killed prey (e.g. blood, skin, etc.) and waste products.
H2O Cycle
Carbon Cycle
- Animals lose carbon by breathing out CO2.
- Plants, through photosynthesis, can take CO2, and turn it into sugars and starches.
- Animals can digest the sugars and starches, using them to build up their bodies, or make energy for themselves.
- Both plants and animals respire, giving back CO2.
- Plants do not move, so their respire much less than animals.
- When you run, do you breath harder? Yes.
Nitrogen Cycle
- Nitrogen Fixation
- Plants and animals cannot use inorganic nitrogen N2. N2 has to be converted (FIXED) into organic nitrogen for plants and animals to use it. Bacteria fix the nitrogen into an organic form.
- Assimilation
- Plants can use nitrogen when it is in the form of NH3. Now plants combine the nitrogen with some of the CO2 that it has made to make proteins.
- Ammonification
- Herbivoures eat plants, bring the new proteins into the animals sections of the food web.
- Animals lose nitrogen in urine and other waste products.
- Nitrification
- Soil bacteria take some of the NH3, and converts it into nitrate (NO3).
- Denitrification
- Other soil bacteria take the NO3, and convert it back into N2.
- Decomposition occurs when animals and plants die, or parts are broken off. The dead body material decomposes with the help of bacteria and fungi, returning ammonia to the nitrogen cycle.
Phosphate Cycle
