Module 6 : Section 6 - Ecosystems

Question 1

What is an ecosystem

Answer 1

All living organisms and non living components and there interactions

Question 2

What is population

Answer 2

Number of individuals of the same species living in the same place at the same time

Question 3

What is community

Answer 3

All the organisms of all the species living in a habitat

Question 4

What is a habitat

Answer 4

Where organisms live

Question 5

What is a niche

Answer 5

The role of an organism in an ecosystem

Question 6

What are biotic factors

Answer 6

Living organisms that affect the environment

Question 7

Abiotic factors?

Answer 7

Non living factors that affect the environment

Question 8

What is a tropic level

Answer 8

Place in a food chain

Question 9

Secondary consumer?

Answer 9

Eats primary consumer

Question 10

Primary consumer?

Answer 10

Eats producer

Question 11

Biomass?

Answer 11

Mass of a living material in a food chain or web

Question 12

How do you measure biomass

Answer 12

Number of organisms x dry mass

Question 13

Producer?

Answer 13

Makes own food source by using sunlight for photosynthesis and is eaten by primary consumer

Question 14

What is the unit of dry mass

Answer 14

Kg

Question 15

What are advantage of using dry mass

Answer 15

Can more accurately compare the biomass of the organism as different organisms have different water contents which may affect the organisms biomass

Question 16

What is the disadvantage of using dry mass

Answer 16

It kills the organisms as you are removing the water contents so it’s unethical

Question 17

What is dry mass

Answer 17

Mass of the organisms without water

Question 18

How do we get the dry mass value for the calculation

Answer 18

We use a bomb calorimeter. Then we burn the sample in high oxygen pressure. Then we measure the rise in temperature of water

Question 19

Why is biomass always less than the previous level

Answer 19

Net all biomass is eaten e.g.bones
Some biomass is excreted e.g. urine
Some biomass is lost as heat

Question 20

What is the unit for net primary production

Answer 20

KJ m-2 yr-1 or g m-2 yr-1

Question 21

What are factors that could increase primary production

Answer 21

High temp and high levels of sunlight so more photosynthesis and more storage biomass

Question 22

Why do producers only convert 1-3% of sunlight into chemical energy

Answer 22

Not all sunlight hits the chlorophyll, other factors may limit photosynthesis, not all light is absorbed some if reflected

Question 23

What is productivity

Answer 23

Rate at which light energy is converted to chemical potential energy

Question 24

What is efficiency equation

Answer 24

Biomass transfer/ biomass intake x100

Question 25

How can human activity manipulate the transfer of energy in animals

Answer 25

-keeping animals warm by having the, close together or indoors so the ont waste energy on photosynthesis to keep them warm -vaccinate animals against disease so they won’t waste energy on immune response -keep animals inside so won’t waste energy on moving -kill animal before they get mature

Question 26

What is the process of the nitrogen cycle

Answer 26

1) nitrogen in the air is converted into ammonia gas by nitrogen fixing bacteria e.g. Rhizobium 2) the ammonia is then dissolved into ammonium ion 3) the ammonium ion is then converted into nitrides via nitrifying bacteria(nitosomes) 4)the nitride is then converted into nitrates via nitrifying bacteria (Nitrobacter) 5) nitrated then actively transported into plants where it’s either eaten by animals or binds with alpha glucose to make amino acids 5) when the animal and plant dies nitrogen compounds are converted into ammonia gas by saprobians in a process called ammoniafication

Question 27

If a plant or animal is in an area with little oxygen or waterlogged what do they do in the nitrogen cycle

Answer 27

The nitrates are then converted into nitrogen gas in a process called denitrification by denitrifying bacteria as the animal or plant takes the oxygen for respiration

Question 28

What are decomposers?

Answer 28

Decomposers are organisms, such as bacteria and fungi, that break down dead organic matter and waste into simpler inorganic substances, releasing nutrients back into the ecosystem.

Question 29

Describe the process of the carbon cycle.

Answer 29

Carbon dioxide is absorbed by plants during photosynthesis and converted into organic compounds. Carbon is passed through food chains by feeding. Respiration by plants, animals, and microorganisms releases carbon dioxide back into the atmosphere. When organisms die, decomposers break them down and release carbon through respiration. Combustion of fossil fuels and wood also releases carbon dioxide.

Question 30

What are detritivores?

Answer 30

Detritivores are organisms that feed on dead organic matter (detritus), breaking it up into smaller pieces and increasing the surface area for decomposers to act on.

Question 31

What type of digestion do decomposers undergo?

Answer 31

Decomposers carry out extracellular digestion. They secrete digestive enzymes onto dead organic matter and absorb the soluble products.

Question 32

What type of digestion do detritivores undergo?

Answer 32

Detritivores carry out internal (intracellular) digestion. They ingest dead organic matter and digest it inside their digestive system.

Question 33

What is succession?

Answer 33

A: The process by which an ecosystem changes over time.

Question 34

What is primary succession?

Answer 34

A: Succession on newly formed or exposed land where no soil is present.

Question 35

What is secondary succession

Answer 35

Succession where soil is present but there are no plants or animals.

Question 36

What is a pioneer community

Answer 36

The first organisms to colonise an area; low biodiversity, low biomass, less stable (e.g. mosses and lichens).

Question 37

Why are pioneer species important?

Answer 37

They add nutrients to the soil and make it suitable for other plants to grow.

Question 38

What is an intermediate community?

Answer 38

A stage where pioneer species die and enrich the soil, allowing grasses and small flowering plants to grow.

Question 39

What is a climax community

Answer 39

The final stable stage of succession where soil is rich and thick enough to support large plants and trees

Question 40

What happens to smaller plants in the climax community?

Answer 40

A: They are outcompeted for space and nutrients by larger plants (e.g. oak trees).

Question 41

How does biodiversity change during succession?

Answer 41

It increases as more species and larger organisms appear.

Question 42

What is deflected succession

Answer 42

When human activity alters succession and prevents it from reaching a climax community.