LE 16: Energy Flow

Question 1

What is the difference between nutrients and energy in an ecosystem?

Answer 1

Nutrients cycle, energy flows through an ecosystem and is lost

Question 2

What is the general process of energy flow in an ecosystem?

Answer 2

• Plants capture light from the sun and convert it into chemical energy to make sugars
• primary producers and consumers use the energy
• heat is lost and energy ≠ cycle anymore

Question 3

What is the distribution of energy?

Answer 3

1% is captured for the use of photosynthesis
- 60% is used for plant sustainability
- 40% is used for producing plant matter

99% is reflected or not used by plants as heat

Question 4

What is primary production and net primary production?

Answer 4

primary production: The amount of biomass produced by primary producers

Net primary production: the amount of biomass produced by primary producers per unit/area/time
- net production = (NPP)(area) mass/year

Question 5

Where is primary productivity the highest? The lowest?

Answer 5

highest:
- along equator at tropical areas
- areas with more precipitation
- areas with lots of bodies of water

lowest:
- poles
- desert

Question 6

Where does the dry mass of plants come from?

Answer 6

carbon in the air that gets used to produced as carbohydrates
- glucose = energy
- starch = more efficient energy
- lignin + cellulose = structural integrity

Question 7

What is Decomposition and how is CO2 released from it?

Answer 7

Process in which plants are broken down by heterotrophs, especially detrivores in order for organisms in the community to use them.

Process:
- plants take in CO2 for photosynthesis and cellular respiration when there is light
- no light = more net output of CO2
- plants get decomposed = CO2 and other nutrients in other forms released

Question 8

Why aren’t all biomass from primary production able to make it to higher trophic levels? What percentage is sent to the next trophic level?

Answer 8

Energy gets stored in the plant’s tissues and is consumed by secondary consumers before decomposition occurs:
- assimilated into biomass
- used for reproduction
- releases CO2

primary production limits secondary production
- secondary production = how much energy consumers have
- less primary production = less secondary production

ONLY 10% of energy from each trophic level is sent to the next
- energy decreases as trophic levels increases

Question 9

What is consumption efficiency?

Answer 9

how efficient an organism is at converting grain to protein
consumption efficiency = consumed energy/NPP at next trophic level

Question 10

Difference between energy and biomass?

Answer 10

energy = how much is produced

biomass = how much is stored and present

Question 11

How does biomass storage differ in terrestrial vs aquatic ecosystems?

Answer 11

Terrestrial ecosystems store most biomass in primary producers
- upright pyramid

Aquatic ecosystems store most biomass in consumers
- higher turnover of producers
- upside down pyramid

Question 12

How does carbon flow in an ecosystem, in relation to energy?

Answer 12

Photosynthesis and cellular respiration govern the flow of carbon
1. linked to energy
- mitochondria = cellular respiration
- chloroplast: photosynthesis
2. more consumers = more cellular respiration + producers = more photosynthesis
- governs how much carbon is PRESENT in the atmosphere

Question 13

What is the relationship between locations with high primary productivity and carbon sequestration?

Answer 13

places with higher primary productivity = more carbon sequestration
- Boggs ≠ decompose easily
- coral reefs have algae
- rainforests

places with less primary productivity = more cellular respiration/ less carbon sequestration = CO2 and greenhouse gases produced
- solar radiation ≠ escape
- ex. burning fossil fuels and dead animals decomposing = more CO2 = higher temperatures