Ecosystems

Question 1

What’s a pioneer species?

Answer 1

The species/ organisms that arrive first that are adapted to abiotic factors (have a low biodiversity)

Question 2

What’s a climax community?

Answer 2

Species that arrive last that are adapted to biotic factors (have a high biodiversity)

Question 3

What’s a climax community?

Answer 3

The species that arrives last and is adapted to biotic factors (has a high biodiversity)

Question 4

What’s meant by decomposition?

Answer 4

The break down/ conversion of organic matter to inorganic

Question 5

What’s meant by denitrification?

Answer 5

The conversion of nitrates to nitrogen

Question 6

What’s nitrogen fixation?

Answer 6

Conversion of nitrogen into ammonia

Question 7

What’s nitrification?

Answer 7

Conversion of ammonia into nitrite

Question 8

What are biotic factors?

Answer 8

Living conditions within a habitat

Question 9

What are abiotic factors?

Answer 9

Non-living conditions within a habitat

Question 10

What’s meant by ‘biomass’?

Answer 10

The chemical energy store for an organism

Question 11

What’s used by plants to create biomass?

Answer 11

Organic molecules

Question 12

What piece of equipment is used to measure biomass?

Answer 12

Calorimeter

Question 13

The mass of carbon is usually about … the dry mass

Answer 13

…Half…

Question 14

What’s the dry mass?

Answer 14

The mass of an organism after water has been removed

Question 15

What’s Gross Primary Production (GPP)?

Answer 15

The chemical energy stored in plant biomass, in a given area/ volume

Question 16

What’s respiratory loss?

Answer 16

The amount of GPP lost as heat during respiration

Question 17

What’s Net Primary Production?

Answer 17

The chemical energy stored in a plant biomass after respiratory losses

(NPP = GPP - R)

Question 18

What’s Net Production of consumers?

Answer 18

Production of new biomass by consumer

Question 19

How can net production of consumers be calculated?

Answer 19

N = I (F + R)

• N= net production of new biomass by consumers.
• | = chemical energy stored in ingested food.
• F = chemical energy lost to the environment in faces and urine.
• R = chemical energy used in respiration.

Question 20

How can efficiency of energy transfer be calculated?

Answer 20

Total energy consumed / net productivity x 100

Question 21

What are saprobionts?

Answer 21

Microorganisms that feed on dead/ decaying organic matter

Question 22

What’s extracellular digestion?

Answer 22

When sabrobionts secrete enzymes onto dead organic matter

Question 23

What’s the chemical symbol for nitrate ions?

Answer 23

NO₃^-

Question 24

What’s the chemical symbol for nitrite ions?

Answer 24

NO₂^-

Question 25

What's the chemical symbol for ammonium ions?

Answer 25

NH₄⁺

Question 26

How can carbon leave the atmosphere?

Answer 26

By mixing with water vapour and falling as acid rain via precipitation

Question 27

What's combustion?

Answer 27

The burning of biomass/ fossil fuels to release carbon dioxide

Question 28

Are artificial fertilisers organic or inorganic?

Answer 28

Inorganic

Question 29

Are natural fertilisers e.g., manure, organic or inorganic?

Answer 29

Organic

Question 30

What's leaching?

Answer 30

When water soluble plant nutrients are lost from the soil

Question 31

Ways to maximise primary productivity in farming:

Answer 31

* Using pesticides * Maximise plant exposure to light * Irrigation to maximise water supply

Question 32

Ways to reduce energy loss in secondary productivity:

Answer 32

* Antibiotics * Restrict movement of animals * Heating in barns

Question 33

What's succession?

Answer 33

Change in an ecosystem over time

Question 34

When does secondary succession take place?

Answer 34

When parts of an ecosystem are disturbed and remnants of previous community remain

Question 35

What happens to the soil as pioneer species die?

Answer 35

It becomes more nutrient-rich and stable/ less hostile

Question 36

What's deflected succession?

Answer 36

Where ecosystems are disturbed by humans, so succession can't take place

Question 37

What's positive chemotaxis?

Answer 37

Movement towards a chemical stimulus

Question 38

What's the definition of a producer?

Answer 38

Organisms that photosynthesise to make their own food (autotrophs)

Question 39

What's the definition of a consumer?

Answer 39

Organism that eats other organisms

Question 40

What's the definition of trophic levels?

Answer 40

Stage in a food chain

Question 41

What is ecology?

Answer 41

The interactions between organisms and their environment