Topic 5 - Energy And Ecosystems

Question 1

What is a primary producer?

Answer 1

An autotrophic organism that converts light energy into chemical energy via the process of photosynthesis. They formed the base of the food chain in most ecosystems by producing organic compounds from inorganic molecules.

Question 2

What is a primary producers role in an ecosystem?

Answer 2

• primary producers supply energy energy to all other organisms in the ecosystem.
• They convert sunlight into energy-storing molecules like glucose which is used by other organisms for respiration.

Question 3

What are the types of primary producers?

Answer 3

Terrestrial ecosystems: mostly plants such as trees, grasses, and shrubs.

Aquatic ecosystems: include algae and some bacteria.

Question 4

How much of sunlight is captured by plants?

Answer 4

Only 1 - 3% of sunlight is captured by plants and converted into chemical energy.

Question 5

Why is only some of sunlight energy captured by plants?

Answer 5

Energy is lost due to reflection, transmission through leaves, or being in wavelength unsuitable for photosynthesis.

Question 6

What is gross primary production?

Answer 6

The total amount of energy converted from light energy into chemical energy by plants in a given area.

Question 7

What is net primary production?

Answer 7

The energy remaining after plants use some respiration.

Question 8

How do you workout the net primary production?

Answer 8

NPP = GPP - R

R - respiratory losses

Question 9

What is primary production measured in?

Answer 9

kJm-2year-1.
Kilojoules per square metre per year.

Question 10

What is five factors affect primary production?

Answer 10

1. Light availability: more light increases photosynthesis boosting GPP and NPP.
2. Temperature: higher temperature increases enzyme activity enhancing photosynthesis however extreme heat can damage enzymes.
3. Water availability: a lack of water reduces stomatal opening, limiting carbon dioxide uptake and photosynthesis
4. Nutrient availability: nutrients like nitrogen and phosphorus are essential for growth low levels reduce primary production.
5. Carbon dioxide concentration: higher carbon dioxide concentrations can increase photosynthesis rates.

Question 11

What are photosynthetic products?

Answer 11

Organic compounds produced by plants during photosynthesis they provide the chemical energy and carbon skeletons needed for growth.

Question 12

What is biomass?

Answer 12

The total mass of living material in a specific area or volume often measured as the mass of carbon or dry mass of tissue per given area per given time.

Question 13

What is dry mass?

Answer 13

Water content can vary between organisms so to obtain dry mass as sample is dried in an oven at low temperature until the constant mass is achieved.

Question 14

Why do you measure carbon to find out the biomass?

Answer 14

On average carbon content is assumed to make up around 50% of the dry mass.

Question 15

How can biomass determined by calorimetry?

Answer 15

1. A sample of known dry mass is placed in the calorimeter and burned in an atmosphere of pure oxygen.
2. The calorimeter is surrounded by water and the heat released by the burning sample causes the temperature of the water to increase.
   3, the temperature change is measured and the energy content of the sample is calculated using the formula for energy.

Question 16

What is the formula for energy in biomass?

Answer 16

Energy (J) = mass of water (g) x specific heat capacity of water (4.18 J/g C) x temperature change (C)

Question 17

What are the uses of biomass in data?

Answer 17

1. Estimate productivity: biomass is data is used to calculate the net primary productivity and gross primary productivity of ecosystems.
2. Compare ecosystems: biomass provides insights into the energy transfer and efficiency between trophic levels.
3. Conservation and management: helping to understand energy flow and planning sustainable practices for agriculture and ecosystem management.

Question 18

What is the importance of net primary production?

Answer 18

• determines the energy flow in an ecosystem.
• Supports the growth of higher trophic levels such as herbivores and carnivores.
• Affects ecosystem, productivity and biodiversity.

Question 19

What is a trophic level?

Answer 19

It represents the position of an organism in a food chain, indicating its role in the flow of energy through an ecosystem. Energy is transferred between trophic levels, but much is lost at each stage.

Question 20

What is a producer?

Answer 20

Produce their own food through photosynthesis.

Question 21

What is a primary consumer?

Answer 21

Herbivores that feed on the producers.

Question 22

What is the secondary consumer?

Answer 22

Carnivores or omnivores that feed on primary consumers.

Question 23

What is a tertiary consumer?

Answer 23

Predators that feed on secondary consumers.

Question 24

What is a decomposer?

Answer 24

Not a distinct level but recycle nutrients by breaking down dead organic matter.

Question 25

What is a sapriobiont?

Answer 25

A specific group of microorganisms that break down organic matter extracellularly by secreting enzymes and absorbing nutrients.

Question 26

How much energy is transferred to each trophic level?

Answer 26

10% of energy

Question 27

When energy is transferred to the next trophic level. It loses energy through what?

Answer 27

Respiration (heat loss). Excretion and egestion (faeces and urine). Uneaten parts of organisms (bones and fur)

Question 29

What is the energy pyramid?

Answer 29

- Energy decreases as it moves up trophic levels. - This limits the number of trophic levels in a food chain as there is insufficient energy to support a higher levels.

Question 30

What are food webs?

Answer 30

- Interconnected food chains showing multiple feeding relationships in an ecosystem. - More complex food webs lead to greatest ability, as the loss of one species has less impact.

Question 31

What is the importance of trophic levels?

Answer 31

– Describe the energy flow and feeding relationships within an ecosystem. – Helps ecologists understand ecosystems stability and productivity. – Provides insights into biodiversity and the impact of species loss.

Question 32

What is secondary productivity?

Answer 32

The rate at which consumers convert the chemical energy in plants they eat into their own biomass over a specific area and time period.

Question 33

What are the units for secondary productivity?

Answer 33

kJ ha-1 year-1

Question 34

How do you workout gross secondary productivity?

Answer 34

Gross secondary productivity = ingested energy - energy lost in faeces and urine

Question 35

What is the calculation for efficiency of energy transfer?

Answer 35

Efficiency = (energy available at the next trophic level / energy available at the previous trophic level) x 100.

Question 36

How can farmers optimise livestock farming?

Answer 36

Farmers can improve energy transfer efficiency by: - Reducing energy losses (e.g. keeping animals warm to reduce heat loss) - Feeding animals with easily digestible nutrient rich food.

Question 37

How to work out the net production of consumers?

Answer 37

N = I - (F +R) I = chemical energy ingested from food F = energy lost in faeces and urine R = energy lost as heat during respiration

Question 38

What does percentage yield measure?

Answer 38

The efficiency of energy or biomass transfer in ecosystems, particularly in agriculture or food production.

Question 39

What is the formula for percentage yield?

Answer 39

Percentage yield = (actual yield/theoretical yield) x 100 Theoretical yield: the maximum amount of product that could be obtained under ideal conditions.

Question 40

What is three applications of percentage yield are there in agriculture?

Answer 40

1. Maximising efficiency: farmers aim to maximise percentage yield to ensure resources like fertilisers water and en energy are effectively utilised. 2. Sustainable practices: managing health, rotation, and pest control to reduce yield loss while minimising environmental impact. 3. Reducing energy loss: technique such as using greenhouses to control conditions or employee high yield crop varieties..

Question 41

How do farmers reduce respiratory losses in livestock?

Answer 41

- Animals are often kept in controlled environments such as heated bones to reduce the energy loss as heat. - Restricted movement minimise energy expenditure. - High energy diets and rapid growth and increased biomass.

Question 42

How do you farmers improve crop yield?

Answer 42

- Fertilisers provide essential nutrients such as nitrogen phosphorus and potassium to enhance plant growth. - Pesticides would reduce the loss of crops to pests. - Herbicides minimise competition from weeds. - irrigation systems maintain water availability.

Question 43

What are the environmental impacts of farming?

Answer 43

Loss of biodiversity Soil degration Eutrophication Greenhouse gas emissions.

Question 44

Why can farming cause a lot of biodiversity?

Answer 44

Monoculture (growing one species) farming reduces habitat variety. Use of herbicide and pesticides harms non-targeted species including pollinators like bees.

Question 45

Why does farming cause soil degration?

Answer 45

Excessive irrigation may cause soil salinisation. Overuse of land can lead to soil erosion and loss fertility.

Question 46

Why can farming cause eutrophication?

Answer 46

Run-off from fertilisers containing nitrates and phosphate enter water bodies leading to algal blooms. Algal blooms reduce oxygen levels, harming aquatic life.

Question 47

Why does farming result in greenhouse gas emissions?

Answer 47

Livestock farming produces methane a potent greenhouse gas. Intensive farming techniques often rely on fossil fuels.

Question 48

What are 3 sustainable farming practices?

Answer 48

- crop rotation to maintain soil fertility - use of natural pest controls and reduced chemical input. - maintaining hedgerows to enhance biodiversity