1. Productivity

2. Affected by water, nutrients, sunlight
“Productivity” refers to the amount of plant mass produced in a particular area
Ex: ever heard of a garden being “productive”?
Affected by water, nutrients, sunlight

3. Food and Population
The type and amount of food available in any given area affects the population that can be supported by it.
Grain feeds more people than meat. (Remember, since grain is lower on the food chain it has more energy available.)

4. Food and Competitors
If there is an increase in the type of food eaten by a particular animal, that population will increase. This is very apparent when we look at monocultures.
A monoculture results when a single crop is grown on a large field
Population of organisms that feed specifically on that plant increases
Humans must then try to deter these organisms by using pesticides

6. The natural trend is to have a biodiverse ecosystem
Ex. A potato field has an abundance of potato plants. Potato bugs now have lots of food to eat and reproduce. We now have a huge number of potato bugs eating the crop. The farmer then needs to spray the field to stop the bugs from eating up his entire crop.
The natural trend is to have a biodiverse ecosystem
Many different kinds of plants and animals in a given area.

7. Pesticides
Used to control organisms that destroy crops that are useful to humans
Accumulate in an ecosystem
Especially in the higher levels of the food chain
This is called biomagnification.
Ex. The pesticide, DDT is a good example of how biomagnification works. Animals that are lower of the food chain (primary consumers) have less DDT in them. As you get higher in the food chain (secondary and tertiary consumers) the DDT increases.

9. Human Consumption
Humans use and affect more than 20% of the Earth’s productivity
This has a dramatic affect on other species
Giving them less space and resources for all other species
Which has led to an alarming human growth rate (this trend can’t continue much longer)

10. Photosynthesis
Plants take the sun’s energy along with carbon dioxide (CO2) and water to make food (carbohydrates) and oxygen.
Energy (Sunlight) + 6 CO2 + 6 H2O → C6H12O6 + 6 O2
Photosynthesis takes place in chlorophyll, which is found in the cell’s chloroplasts.

11. Cellular Respiration
Organisms breakdown food (carbohydrates) with the help of oxygen to produce carbon dioxide, water and energy.
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy
Cellular respiration takes place in the cell’s mitochondrion
mitochondria is pleural

12. NOTE: Cellular respiration is simply photosynthesis in reverse.
Only producers practice photosynthesis, but all organisms (including producers) carry out cellular respiration.