Unit 1 - AOS1 - Ecological relationships and Energy Transfer

Question 1

How does energy enter the ecosystem?

Answer 1

Solar Energy (sunlight)

Question 2

What are autotrophs?

Answer 2

Convert solar energy to chemical energy (photosynthesis)

Question 3

What are heterotrophs?

Answer 3

They obtain chemical energy by eating autotrophs (assimilation)

Question 4

Photosynthesis

Answer 4

Light
Carbon dioxide + water ——————->
chlorophyll
= glucose + oxygen

Question 5

Trophic levels

Answer 5

First tropic level = producer (autotrophs)
Secondary level = primary consumer (heterotrophs)
Third tropic level = secondary consumer
Trophic level = tertiary consumer

Question 6

Food chain

Answer 6

A visual representation of interactions between organisms

The flow of nutrients and energy from one organism to another at different trophic levels forms a food chain

Question 7

Food webs

Answer 7

• Food webs represent multiple interactions within an ecosystem
• One organism can be at multiple tropic levels in the food chain within the food web

Question 8

Definition of biomass

Answer 8

The total quantity or weight of organisms in a given area or volume

Question 9

2nd Law of thermodynamics

Answer 9

2nd LAW OF THERMODYNAMICS:
————————————————–
NO ENERGY TRANSFORMATION IS 100%
EFFICIENT

• ~90% of energy is lost (as heat) with each transformation
• Only 10% of energy is moved into the next trophic level

Question 10

Formular for energy transfer

Answer 10

Energy Amount x 0.1 = Amount of energy passes on to next trophic level (10%)

Example:
Grass (100kJ) —> cricket (10kJ)
(100 x 0.1 = 10kJ)

Question 11

Characteristics of biomass pyramid

Answer 11

• show the biomass of each trophic level in a food chain
• mass in level generally decreases (levels get smaller)

Question 12

Reasons why only 10% of biomass gets passed on:

Answer 12

1. organisms don’t normally every part (bones or teeth)
2. bits they do eat might not be absorbed get egested as feces
3. most of the nutrients that animals absorb is used to release energy through respiration.

Question 13

Charateristics of Decomposers

Answer 13

• Heterotrophs
• breakdown and consume organic waste and dead organisms
• examples are bacteria, fungi, some protozoans (single cell organisms)
• Usually left off a food web or chain
• important for cycling nutrients (required for autotrophs)
• In their own trophic level (consume all other trophic levels)

Question 14

Reasons why only 10% of biomass/energy is transferred

Answer 14

1. Organisms don’t normally eat every part (skull, bones teeth)
2. Parts they do might not be absorbed  (get egested as feces)
3. Most of the nutrients that animals absorb used to release energy through respiration Released energy as respiration