1. Ecology: Chapter 18
Ecology is the study of the interactions between organisms and their environment:
-biotic: living components
-abiotic: nonliving components
-This quality is called interdependence.

2. Levels of Organization
Biosphere contains the combined portions of the planet in which all life exists, including, land, water, and air.
It extends from about 5 miles above the Earth’s surface to the deepest parts of the ocean
The biosphere contains smaller ecosystems:
a collection of all the organisms that live in a particular place, together with the nonliving environment

3. Levels of Organization
Communities are groups of different populations that live together in a defined area. It may contain a few or a thousand species interacting together.
Only contains biotic factors
Populations are groups of individuals that belong to a single species AND live in the same area
Species is a group of organisms so similar to one another that they can breed and produce fertile offspring

4. Energy Flow
Make a food web on your paper showing the relationships and flow of energy between the following organisms: cherry tree, earthworm, robin, butterfly, frog, rabbit, squirrel, fox, snake, and eagle
Hints:
Producer: tree
Herbivores: earthworm, butterfly, rabbit, squirrel
Omnivores: robin
Carnivores: frog, fox, snake, eagle

5. Does your Flow of Energy look like this?
Identify the producers (P), Primary consumers (1°C), Secondary consumers (2°C), Tertiary consumers (3°C), and Quaternary (4°C)
In addition:
Detritivores: feed on waste or detritus (including dead organisms, fallen leaves and animal wastes.
Decomposers: many bacteria and fungi cause decay by breaking down complex materials into simpler molecules. They return the nutrients to the environment.

6. More on Energy Flow
When an organism eats another, molecules are broken down and energy is transferred
An organism’s trophic level, indicates its position in the sequence of energy levels.
Most ecosystems have only 3-4 trophic levels
Why only 3-4 trophic levels?
Rule of 10

7. More on Producers
Chemosynthesis: some autotrophic bacteria do not use sunlight to make their own food. They use chemicals not containing carbon (inorganic)
Photosynthesis: most organisms use this process to make their own food
6CO2 + 6 H2O + sunlight –> C6H12O6 + 6O2

8. More on Producers
Gross Primary Productivity: the rate that producers are able to make organic compounds
Biomass: The organic material that has been produced in an ecosystem. Producers make biomass
Net Primary Productivity…the rate biomass accumulates
NPP = GPP – producer respiration rate

9. How Do Organisms Handle A Changing Environment?
An organism can survive and function in conditions outside its optimal range, but its performance is reduced.
Acclimation: how some organisms adjust their tolerance to abiotic factors (NOT the same as adaptation)
When environments fluctuate:
Conformers: change with environmental conditions
Regulators: use energy to control some of their internal conditions
Escape from Unsuitable Conditions
Hide in the shade during hot part of the day
Dormancy: enter a state of reduced activity
Migration: move to favorable habitat

10. The NICHE
Niche:
the range of conditions a species can tolerate,
the resources it uses (and how it obtains resources),
the number of offspring,
its time of reproduction,
Other interactions with its environment
Generalists: broad niche; can handle a large range of conditions
Specialists: narrow niche

11. Biogeochemical Cycles

12. Biogeochemical Cycles
THE CARBON CYCLE

13. Biogeochemical Cycles
The NITROGEN CYCLE provides Nitrogen for proteins and nucleic acids
Nitrogen gas makes up 78% of the atmosphere,
Plants can only use nitrogen in the form of nitrate.
Converting Nitrogen gas to nitrate is called nitrogen fixation.
Nitrogen fixing bacteria: transform nitrogen into a usable form.
Words to know from your text: ammonification, nitrification, denitrification

14. Biogeochemical Cycles
The PHOSPHORUS CYCLE: the essential material for bones, teeth, DNA and RNA
When rocks erode, small amounts of phosphorus dissolve as phosphate (and from fertilizer and decomposing organisms)
Plants absorb phosphorus
Animals eat plants,
ETC.