REVIEW ECOLOGY UNIT
- Sustainability
- Ecological Footprints
- Food Chains & Food Webs
o Autotroph vs. Heterotroph
o Trophic Levels
o Producer & Consumer
o Food web vs. Food Chain
o Biotic and Abiotic factors
o Decomposers
o Top Carnivore
FOOD CHAIN
GrassàRabbitàFox
Producer, primary consumer, secondary consumer
First trophic level, second trophic level, third trophic level
FOOD WEB
1) List the producer? Krill
2) Any omnivores? Humpback whale
3) What trophic level is leopard seal? 3, 4
4) Organism that’s a secondary consumer?
a. Leopard seal
b. Emperor penguin
c. Adelie penguin
d. Petrel
5) Any decomposers listed? No
Energy Levels à 10% passed to the next trophic level; 90% used
Grass à rabbit à fox (start with 100kJ energy)
Grass -- 100kj – 90 used –10 stored
Rabbit -- 10 to start – 9 used – 1 stored
Fox -- 1 to start – 0.9 used – 0.1 stored
Pyramid of biomass – more biomass from producers than top consumers
pyramid of energy flow – more energy in producers than top consumers
pyramid of numbers – more organisms in producers than consumers
Populations – group of organisms of the same species living in the same place at the same time
- Carrying Capacity
- Competition
o Interspecific competition
o Intraspecific competition
- Population Denisty
o Density dependant factors
o Density independent factors
- Population growth, explain the three types of graphs
o Exponential growth (unlimited resources)
o Population crash (grow too fast and then cant recover)
o Predatory Prey Relationships (s-shaped curve)
- Productivity (warm, wet areas are more productive)
- Factors affecting productivity (sunlight, water, carbon dioxide, nitrogen, phosphorous & temperature)
- Changing productivity
- Leads to pesticide use
- Biological Magnification (LOTS more poison at the top of the food chain!!)
- DDT!!
Carbon Cycle
1) Photosynthesis à plants take in carbon from atmosphere (CO2) & convert it into carbon in its tissues
2) Cellular Respiration à organisms release CO2 into the atmosphere after they use the sugars (carbon!!) they made/ingested to make energy.
3) Decay à when organisms get rid of waste or die, decomposers break down the tissues and release carbon into the atmosphere as methane and CO2 or into the soil and it can be made into sediments and fossil fuels
4) Combustion à burning the fossil fuels that have been stored underground for millions of years releases CO2 into the atmosphere
*** Diagram
Humans affect the carbon cycle by: burning fossil fuels and deforestation
Global Warming – increased greenhouse gasses in the atmosphere, don’t let the heat from the sun escape and the earth heats up. It has many different effects.
Nitrogen Cycle
1) Nitrogen exists as N2 gas in the atmosphere, which isn’t usable by anything.
2) It has to be fixed (join with O or H). Nitrogen fixation is the step that does that. It creates ammonia and nitrates. Do so mostly by bacteria. Also lightning or artificially.
3) Ammonification à bacteria takes the ammonia and converts it to ammonium which is now useful to plants.
4) Nitrification àbacteria convert ammonia in the soil into nitrite. Bacteria then convert nitrites into nitrates which are usable by plants.
5) Denitrification à puts nitrogen gas back into the atmosphere. Bacteria will break apart the nitrates in the soil into nitrogen gas and oxygen gas. They use the oxygen gas to survive and release the nitrogen gas back into the atmosphere.
Extinction
Endangered Species
Threatened Species