3.5.3 Energy and Ecosystems

Question 1

What is a trophic level?

Answer 1

The pattern of energy flow in a food chain

Question 2

What is the basic food chain diagram?

Answer 2

Sun = Producers = Consumers

= Decomposers

Question 3

What are the types of consumers?

Answer 3

Primary, secondary, tertiary… etc

Depends on the food chain in relation to the producers

Question 4

Are plants the only type of producers?

Answer 4

No, algae and some bacteria are producers

Question 5

Which way do arrows point in a food chain diagram?

Answer 5

Towards the consumer

Question 6

What is biomass?

Answer 6

When sugars that aren’t used up by the plant are used to make biological molecules, these molecules from the biomass of the plant

Question 7

How can biomass be measured?

Answer 7

In terms of mass of carbon or dry mass of tissue per given area
Can be estimated using calorimetry

Question 8

What is ecology?

Answer 8

The study of how organisms interact with one another in their environment

Question 9

What is an individual?

Answer 9

A single organism in a population

Question 10

What is a population?

Answer 10

A group of individuals of the same species occupying a given area at the same time

Question 11

What is a community?

Answer 11

All the populations living in a defined area

Question 12

What is a habitat?

Answer 12

The area where an organism lives, including where it finds food and mates

Question 13

What is a niche?

Answer 13

Where an organism lives and what it does there

Question 14

What is an ecosystem?

Answer 14

A community plus all the abiotic factors

Question 15

What is a biosphere?

Answer 15

All of the Earth’s ecosystems

Question 16

What is a biome?

Answer 16

Large regions characterised by certain climates

Question 17

What are the limiting factors in aquatic environments?

Answer 17

Salinity, dissolved oxygen content, light, temperature

Question 18

How much of the sun’s energy do plants convert into organic molecules?

Answer 18

1 - 3%

Question 19

Why is so little of the sun’s energy converted into organic molecules by plants?

Answer 19

Misses chloroplasts
Is reflected
Not all waves of light can be absorbed
CO2 becomes limiting

Question 20

What is primary productivity?

Answer 20

The amount of new biomass of producers per unit time and space, measured in kJ/m2/year

Question 21

What is gross primary production?

Answer 21

The total amount of energy captured

Question 22

What is the equation for net primary production?

Answer 22

GPP - respiration

Question 23

What is net primary production?

Answer 23

The amount of energy available to consumers and decomposers

Question 24

Why doesn’t 100% of the energy from food not go into primary consumers?

Answer 24

Some lost in growth and reproduction
Not all of the plant is available
Some parts can not be digested
Some energy is lost in excretotry materials
Energy is needed to have a high body temperature

Question 25

What is the equation for energy efficiency?

Answer 25

Energy available after the transfer
————————————————— X 100
Energy available before the transfer

Question 26

What is the equation for net production?

Answer 26

N = I - ( F + R )
I = energy in ingested food
F = energy in faeces
R = energy in respiration