NA. 6.5 Ecosystems, Not on adv

Question 1

Define Sustainable resource

Answer 1

A renewable resource which is being economically exploited in such a way that it will not diminish or run out

Question 2

Define Ecosystem

Answer 2

All the interacting living organisms and non living conditions in an area

Question 3

Define Decomposition

Answer 3

Chemical reactions in which a compound is broken down into simpler compounds or its constituent elements

Question 4

Define Interspecific competition

Answer 4

Competition between organisms of different species

Question 5

Define Intraspecific competition

Answer 5

Competition between organisms of the same species

Question 6

Define Ecological efficiency

Answer 6

The efficiency with which energy or biomass is transferred from one trophies level to the next

Question 7

Define Biomass, how can we measure this?

Answer 7

The total weight of living matter in a certain area, transferred up trophic levels through consumption. Can be measured in terms of mass of carbon, or dry mass of tissue.

Question 8

Define Hummus

Answer 8

The organic component of soil formed by the decomposition of leaves and other plant material by soil microorganisms

Question 9

Define Decomposer

Answer 9

An organism that breaks down dead organisms releasing nutrients back into the ecosystem

Question 10

Define Trophic level

Answer 10

Stage in a food chain

Question 11

Define Plagioclimax

Answer 11

The stage in succession where artificial or natural factors prevent the natural climax community from forming

Question 12

Define Carrying capacity

Answer 12

The maximum population size that an environment can support

Question 13

Define Dominant species

Answer 13

The most abundant species in an ecosystem

Question 14

Define Seral stages

Answer 14

The stages of succession

Question 15

Describe Biotic and Abiotic factors, giving examples

Answer 15

Biotic= living features of an ecosystem
e.g. predators, disease.
Abiotic= non-living features of an ecosystem e.g. light, temperature.

Question 16

How can human activities affect biomass transfer?

Answer 16

• Light, water, temperature maximised.
• Increased nutrients in soil.
• Pests and weeds removed.
• Growth rates boosted through steroids, selective breeding, etc.

Question 17

Outline the roles of microorganisms in the Nitrogen cycle.

Answer 17

• Nitrogen-fixing bacteria e.g. Rhizobium in roots and Azotobacter in soil, convert gaseous nitrogen into ammonia.
• Nitrifying bacteria e.g. Nitrosomonas convert ammonium compounds into nitrites. Nitrobacter then convert nitrites to nitrates.

Question 18

Outline the role of organisms in the Carbon cycle.

Answer 18

• Respiration of plants and animals add carbon dioxide into the atmosphere.
• Photosynthesis of plants removes carbon dioxide from the atmosphere.
• Decomposers (microorganisms) decay plant and animal material into carbon dioxide.

Question 19

What is meant by Primary succession?

Answer 19

Where an area previously devoid of life is colonised by a community of organisms.

Question 20

Summarise the process of Primary succession.

Answer 20

1. Pioneer species, able to survive harsh conditions, colonise the area.
2. They die, decompose, and add nutrients to the ground.
3. Over time, this allows more complex organisms to survive.

Question 21

What is the Climax community and how is it reached?

Answer 21

The final stage of succession, where the ecosystem is balanced and stable. It is reached when the soil is rich enough to support large trees or shrubs, and the environment is no longer changing.

Question 22

What is Deflected succession?

Answer 22

Where succession is interrupted, usually by human interference.

Question 23

What is Sampling?

Answer 23

Selecting a group of individuals that will represent the whole target population. Allows us to measure the distribution and abundance of organisms.

Question 24

Give methods of sampling and explain how they are used.

Answer 24

• Quadrats= used in small areas. Randomly or regularly placed across habitat. Frequency or % cover calculated.
• Transects= used in larger areas. Sample taken along a line that crosses the habitat. Can be

Question 25

What is a Pioneer species?

Answer 25

a species that begins the succession process, often colonizing and making it habitable

Question 26

What is Gross Primary Productivity?

Answer 26

The rate at which plants convert light to chemical energy(through photosynthesis)

Question 27

What is Net Primary Productivity?

Answer 27

The energy from the sun that enters the food chain (a very little amount aproxx between 1-8%)

Question 28

How can you improve Primary productivity?

Answer 28

Drought and pest resistant plants to prevent deaths
Crop rotation to maximise available nutrients
Any method hat improves photosynthesis:
• Maximising light levels (ligh banks etc.)
• Growing plants in green houses( warmer temps)

Question 29

How can you improve Secondary productivity?

Answer 29

• selectively breed animals with faster growth and Yield rates
• Treat animals with medicine to prevent unnecessary deaths
• keep animals in temp controlled cages so they don’t wast energy finding food and thermoregulating
• kill animals just before adulthood

Question 30

In what ways are energy and material lost from the food chain?

Answer 30

energy may be lost as
• heat (released during respiration),
• through movement,
• in materials that the consumer does not digest (dead organism that only decomposers use)