Topic 4.2

Question 1

Photoautotrophs

Answer 1

use pigments such as chlorophyll to capture light energy and convert into chemical energy as carbon compounds

Question 2

chemoautotrophs

Answer 2

produce their own energy from chemical processes (e.g. volcanic vents in the ocean floor)

Question 3

Heterotrophs (in relation to sunlight)

Answer 3

Rely indirectly on sunlight

Question 4

Autotrophs (in relation to sunlight)

Answer 4

Use sunlight to convert carbon dioxide into organic compounds (glucose)

• light energy is transferred into bonds (chem. energy) btwn atoms in carbohydrate molecules
• molecules converted into carbohydrates, lipids, amino acids
• most of energy is retained in plant structure and is available to heterotrophs

Question 5

Food chains

Answer 5

The flow of energy through the tropic levels by feeding relationships (lose 10% of energy each lvl)

Question 6

Energy conversions (list)

Answer 6

Light —> chemical = photosynthesis
Chemical —> kinetic = muscle contraction
Chemical —> electrical = nerve cells

Question 7

True or false: ecosystems require a continuous supply of energy (e.g. sunlight) to exist

Answer 7

True

Question 8

Biomass

Answer 8

Total mass of a group of organisms
- biomass contains carbon compounds (which contain chem. energy): indirect measurement of chemical energy

Question 9

Why is not all energy transferred?

Answer 9

• not everything is ingested, not all energy digested/assimilated, food is excreted, energy lost as heat from respiration