1.9 & 1.10 - Trophic Levels and 10% Rule

Question 1

T or F (You better get this right)
Matter and energy is never created nor destroyed

Answer 1

True!

Question 2

What is the 1st law of thermodynamics

Answer 2

Energy is never created nor destroyed

Question 3

What are two things that demonstrate the conservation of matter/energy?

Answer 3

• Biogeochem. cycles demonstrate conservation of matter (C/N/H2O/P)
• Food webs demonstrate conservation of energy
  - When a rabbit eats a leaf, the energy from the leaf (glucose) is transfered to the rabbit & stored as body tissue like fat/muscle

Question 4

What is the 2nd law of thermodynamics

Answer 4

Everytime energy is transfered, some of it is lost as heat

Question 5

How is the 2nd law of thermodynamics applied to food webs

Answer 5

the amount of useable energy decreases as you move up the food chain (organisms use up most of it for movement, development, etc.)

Question 6

Explain the 10% rule

Answer 6

In trophic pyramids, only about 10% of the energy from one level makes it to the next level; the other 90% is used by the organism & lost as heat

Question 7

How does the 10% rule apply to biomass?

Answer 7

Since energy is needed for growth & only 10% of energy transfers from one level to the next, only 10% of the biomass can be grown/supported

Question 8

Explain the 4 main producers and consumers

Answer 8

1. Tertiary consumer - animals that eat the secondary consumer or carnivores and omnivores (aka - top/apex predator)
2. Secondary consumer - animals that east primary consumers or herbivores (aka - carnivores and omnivores)
3. Primary consumers - animals that eat plants (herbivores)
4. Producers (plants) - “produce”/convert the suns light energy into chemical energy (glucose)