Energy Flow in Ecosystems

Question 1

What is an energy transfer?

Answer 1

Energy transfer is the movement of one type of energy from one object to another.

Question 1

What is an energy transformation?

Answer 1

Energy transformation is when one type of energy is converted into another type of energy.

Question 2

Give an example of energy transfers.

Answer 2

When one animal feeds on another the chemical potential energy from the prey is transferred to the predator.

Question 3

Give an example of energy transformation.

Answer 3

During photosynthesis plants transform light energy from the sun into chemical potential energy stored in glucose.

Question 4

What is an autotroph?

Answer 4

An organism capable of making its own food from inorganic substances using light energy through photosynthesis.

Question 5

Give some examples of autotrophs.

Answer 5

Includes plants, algae and some bacteria.

Question 6

What is a chemotroph?

Answer 6

An organism capable of making its own food from inorganic substances using chemical energy through chemosynthesis.

Question 7

Give some examples of chemotrophs.

Answer 7

Includes archea and some bacteria.

Question 8

What is a heterotroph?

Answer 8

An organism that cannot synthesise its own organic compounds from simple inorganic materials; it depends on other organisms for nutrients and energy requirements.

Question 9

Give some examples of heterotrophs.

Answer 9

Consumers.

Question 10

What is a consumer?

Answer 10

Organisms that acquire energy by consuming other organisms.

Question 11

What is a producer?

Answer 11

Organisms with features that allow them to manufacture food in the form of organic matter using the energy in sunlight.

Question 12

What is are trophic levels?

Answer 12

The feeding levels in a food chain.

Question 13

What is biomass?

Answer 13

The total mass of biological matter living or dead, in a given area, at the time of measurement that can be used as an energy source.

Question 14

Is water counted as biomass?

Answer 14

As water is does not contain energy biomass if generally measured as dry weight per unit area.

Question 15

What is the chemical equation of photosynthesis?

Answer 15

6CO2 + 6H2O → C6H12O6 + 6O2

Question 16

What is the chemical equation of chemosynthesis?

Answer 16

18H2S + 6CO2 + 3O2 → C6H12O6 (carbohydrate) + 12H2O + 18S

Question 17

What is photosynthesis?

Answer 17

Photosynthesis is the process in which light energy is converted to chemical energy in the form of sugars.

Question 18

What is chemosynthesis?

Answer 18

Chemosynthesis is the process by which food (glucose) is made by bacteria using chemicals as the energy source, rather than sunlight.

Question 19

What are food chains?

Answer 19

A food chain is a linear sequence of organisms through which nutrients and energy pass as one organism eats another.

Question 20

What do the arrows in food chains show?

Answer 20

The arrows show the direction of energy transfer from one organism to another.

Question 21

What is the order of organisms in a food chain?

Answer 21

Producer —> Primary consumer (herbivore) —> Secondary consumer (second-order consumer) —> Tertiary consumer (third-order consumer) —> Top carnivore (apex predator)

Question 22

What do primary consumers feed on?

Answer 22

Primary consumers feed on producers (herbivores).

Question 23

What do secondary consumers feed on?

Answer 23

Secondary consumer (carnivore) feeds on primary consumers.

Question 24

What do top consumers feed on?

Answer 24

Top consumers (apex predator) feed on secondary consumers.

Question 25

What do omnivores feed on?

Answer 25

Ominvore feeds on both plants and animals.

Question 26

What do scavengers feed on?

Answer 26

Scavengers feed on the dead remains of other organisms.

Question 27

What do detritivores feed on?

Answer 27

Detritivores feed on the dead or decaying organic remains and wastes. Larger than decomposers. Speed up decay by breaking down larger pieces of detritus and increasing the surface area for decomposers to be exposed to.

Question 28

What is detritus?

Answer 28

Dead or decaying organic matter/wastes.

Question 29

What is the role of a decomposer?

Answer 29

Decomposers break down complex organic molecules to form simpler inorganic molecules and return nutrients to the soil.

Question 30

What is the 10% rule?

Answer 30

The 10% rule in ecology states that, on average only about 10% of the energy at one trophic level is passed on to the next level. The remaining 90% is lost to the surroundings as heat energy and chemical energy.

Question 31

Do all feeding relationships relate to the 10% rule?

Answer 31

No, some feeding relationships can have a higher trophic efficiency. E.g. zooplankton feeding on phytoplankton can have up to 40% efficiency.

Question 32

What is trophic efficiency?

Answer 32

Trophic efficiency describes how much energy is available from one level to the next within a food chain.

Question 33

What are food webs?

Answer 33

Integrated food chains showing all of the feeding relationships in an ecosystem.

Question 34

Why do we use food webs?

Answer 34

• It is rare that a simple food chain would exist in nature as most organism rely on multiple food sources.
• Therefore we use food webs to show some organisms can occupy more than one position.

Question 35

What is a pyramid of numbers?

Answer 35

A pyramid of numbers is a graphical representation that shows the number of organisms at each trophic level.

Question 36

What is an inverted pyramid of numbers?

Answer 36

An inverted pyramid of numbers shows the results of a community that contains parasites.

Question 37

What do the rectangles show in a pyramid of numbers?

Answer 37

The width of each rectangle indicates the relative numbers of organisms at each trophic level.

Question 38

When does an inverted pyramid of numbers occur?

Answer 38

When more organisms occupy the trophic level above the preceding level.

Question 39

What is a pyramid of biomass?

Answer 39

A pyramid of biomass is a graphical representation of biomass present in a unit area of various trophic levels. It shows the relationship between biomass and trophic level quantifying the biomass available in each trophic level of an energy community at a given time.

Question 40

When does an inverted pyramid of biomass occur?

Answer 40

Inverted biomass pyramids can occur during certain times of year. For example, during some pyramids that number of zooplankton (primary consumers) outweigh the number of phytoplankton (producers).

Question 41

What does the biomass decreasing at each successive trophic level tell us about consumers?

Answer 41

Consumers must eat considerable amounts of food to fulfil their energy needs.

Question 42

What is a pyramid of energy?

Answer 42

A pyramid of energy shows the total quantity of available energy stored in the biomass of organisms at each level in the food chain of an ecosystem per year.
Shows the energy transfer through successive trophic levels.

Question 43

What must the rectangles in a pyramid of energy be?

Answer 43

The size of the rectangle above must be drawn as 10% of the rectangle below (the 10% rule).