Unit 5 (Ecology- Energy Flow & Chemical Cycling)

Question 1

Define Energy.

Answer 1

The capacity to do work and/or produce heat.

Question 2

What is the 2nd Law of Thermodynamics?

Answer 2

Every time energy is converted from 1 form to another, some of it is converted to heat. Heat is the least usable for work.

Question 3

What do Food Chains represent?

Answer 3

The flow of energy through an ecosystem.

Question 4

Give an example of a food chain with a producer, a primary consumer, and a secondary consumer.

Answer 4

Ex.
grass -> grasshopper-> mouse-> hawk

Question 5

What is a food web?

Answer 5

We use a food chain to understand energy transfer, but a food web is what the actual animal kingdom resembles.

Question 6

What is a Trophic Level? Draw a Trophic Pyramid of chemical energy.

Answer 6

A step of the food chain. (T level one or two etc.)

Question 7

What is the 10% Rule?

Answer 7

Only 10% of the chemical energy consumed by a given level is actually stored as chemical energy by that level.

Question 8

What are the three reasons that only 10% of chemical energy consumed is stored per trophic level?

Answer 8

1. Most of the energy consumed is spent.
2. 2nd Law of Thermodynamics
3. Only some parts of a meal are digestable.

Question 9

Why is eating high up on the food chain energy wasteful?

Answer 9

Because of the 10% rule.

Question 10

How can eating higher up on the food chain harm us physically?

Answer 10

We become exposed to higher level of toxins, like Mercury. (Bc of biomagnification)

Question 11

What is Biomagnification?

Answer 11

The increase in concentration of insoluble toxins in successively higher trophic levels.

Question 12

What is Biogeochemical Cycling?

Answer 12

The movement and transformation of chemicals through different mediums in a cyclical fashion.

Question 13

Draw a quick sketch of the Terrestrial Carbon Cycle.

Answer 13

Check your notes.

Question 14

Walk yourself through the Nitrogen Cycle.

Answer 14

Plants have nitrogen-> we eat plants-> we can’t digest Nitrogen, we shit it out/or die in the soil-> back into the soil
(plants->animals->decomposers->plants)

Question 15

What are the two chemicals that make up the air? In what percentages?

Answer 15

1. Nitrogen and Oxygen
2. O2 (20%) N2 (80%)
   (+CO2 (.04%))

Question 16

What is Nitrogen Fixation?

Answer 16

The chemical process in which certain bacteria converts nitrogen to nitrates.

Question 17

What are three ways carbon dioxide is “made”?

Answer 17

1. Cell Respiration (exhaling)
2. Decomposition (releases CO2)
3. Combustion (of coal/oil releases CO2)

Question 18

What is Eutrophication?

Answer 18

This is when agricultural runoff fills a body of water with nitrates and causes an algae bloom.
This then causes a depletion of O2 and sunlight, and all the fish die.

Question 19

What is a “Dead Zone?” What causes this?

Answer 19

1. A biological desert where there is no more life.
2. Eutrophication. (Algae Blooms suffocated the wildlife)

Question 20

True or False?
Matter on earth cycles, but energy does not.

Answer 20

True! Energy flows in a singular direction but does not cycle. Energy is constantly turning into heat.