Topic 5 - Energy And Ecosystems Flashcards
What is a primary producer?
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.
What is a primary producers role in an ecosystem?
- 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.
What are the types of primary producers?
Terrestrial ecosystems: mostly plants such as trees, grasses, and shrubs.
Aquatic ecosystems: include algae and some bacteria.
How much of sunlight is captured by plants?
Only 1 - 3% of sunlight is captured by plants and converted into chemical energy.
Why is only some of sunlight energy captured by plants?
Energy is lost due to reflection, transmission through leaves, or being in wavelength unsuitable for photosynthesis.
What is gross primary production?
The total amount of energy converted from light energy into chemical energy by plants in a given area.
What is net primary production?
The energy remaining after plants use some respiration.
How do you workout the net primary production?
NPP = GPP - R
R - respiratory losses
What is primary production measured in?
kJm-2year-1.
Kilojoules per square metre per year.
What is five factors affect primary production?
- Light availability: more light increases photosynthesis boosting GPP and NPP.
- Temperature: higher temperature increases enzyme activity enhancing photosynthesis however extreme heat can damage enzymes.
- Water availability: a lack of water reduces stomatal opening, limiting carbon dioxide uptake and photosynthesis
- Nutrient availability: nutrients like nitrogen and phosphorus are essential for growth low levels reduce primary production.
- Carbon dioxide concentration: higher carbon dioxide concentrations can increase photosynthesis rates.
What are photosynthetic products?
Organic compounds produced by plants during photosynthesis they provide the chemical energy and carbon skeletons needed for growth.
What is biomass?
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.
What is dry mass?
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.
Why do you measure carbon to find out the biomass?
On average carbon content is assumed to make up around 50% of the dry mass.
How can biomass determined by calorimetry?
- A sample of known dry mass is placed in the calorimeter and burned in an atmosphere of pure oxygen.
- 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.
What is the formula for energy in biomass?
Energy (J) = mass of water (g) x specific heat capacity of water (4.18 J/g C) x temperature change (C)
What are the uses of biomass in data?
- Estimate productivity: biomass is data is used to calculate the net primary productivity and gross primary productivity of ecosystems.
- Compare ecosystems: biomass provides insights into the energy transfer and efficiency between trophic levels.
- Conservation and management: helping to understand energy flow and planning sustainable practices for agriculture and ecosystem management.
What is the importance of net primary production?
- determines the energy flow in an ecosystem.
- Supports the growth of higher trophic levels such as herbivores and carnivores.
- Affects ecosystem, productivity and biodiversity.
What is a trophic level?
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.
What is a producer?
Produce their own food through photosynthesis.
What is a primary consumer?
Herbivores that feed on the producers.
What is the secondary consumer?
Carnivores or omnivores that feed on primary consumers.
What is a tertiary consumer?
Predators that feed on secondary consumers.
What is a decomposer?
Not a distinct level but recycle nutrients by breaking down dead organic matter.
What is a sapriobiont?
A specific group of microorganisms that break down organic matter extracellularly by secreting enzymes and absorbing nutrients.
How much energy is transferred to each trophic level?
10% of energy
When energy is transferred to the next trophic level. It loses energy through what?
Respiration (heat loss).
Excretion and egestion (faeces and urine).
Uneaten parts of organisms (bones and fur)
What is the energy pyramid?
- 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.
What are food webs?
- 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.
What is the importance of trophic levels?
– 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.
What is secondary productivity?
The rate at which consumers convert the chemical energy in plants they eat into their own biomass over a specific area and time period.
What are the units for secondary productivity?
kJ ha-1 year-1
How do you workout gross secondary productivity?
Gross secondary productivity = ingested energy - energy lost in faeces and urine
What is the calculation for efficiency of energy transfer?
Efficiency = (energy available at the next trophic level / energy available at the previous trophic level) x 100.
How can farmers optimise livestock farming?
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.
How to work out the net production of consumers?
N = I - (F +R)
I = chemical energy ingested from food
F = energy lost in faeces and urine
R = energy lost as heat during respiration
What does percentage yield measure?
The efficiency of energy or biomass transfer in ecosystems, particularly in agriculture or food production.
What is the formula for percentage yield?
Percentage yield = (actual yield/theoretical yield) x 100
Theoretical yield: the maximum amount of product that could be obtained under ideal conditions.
What is three applications of percentage yield are there in agriculture?
- Maximising efficiency: farmers aim to maximise percentage yield to ensure resources like fertilisers water and en energy are effectively utilised.
- Sustainable practices: managing health, rotation, and pest control to reduce yield loss while minimising environmental impact.
- Reducing energy loss: technique such as using greenhouses to control conditions or employee high yield crop varieties..
How do farmers reduce respiratory losses in livestock?
- 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.
How do you farmers improve crop yield?
- 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.
What are the environmental impacts of farming?
Loss of biodiversity
Soil degration
Eutrophication
Greenhouse gas emissions.
Why can farming cause a lot of biodiversity?
Monoculture (growing one species) farming reduces habitat variety.
Use of herbicide and pesticides harms non-targeted species including pollinators like bees.
Why does farming cause soil degration?
Excessive irrigation may cause soil salinisation.
Overuse of land can lead to soil erosion and loss fertility.
Why can farming cause eutrophication?
Run-off from fertilisers containing nitrates and phosphate enter water bodies leading to algal blooms.
Algal blooms reduce oxygen levels, harming aquatic life.
Why does farming result in greenhouse gas emissions?
Livestock farming produces methane a potent greenhouse gas.
Intensive farming techniques often rely on fossil fuels.
What are 3 sustainable farming practices?
- crop rotation to maintain soil fertility
- use of natural pest controls and reduced chemical input.
- maintaining hedgerows to enhance biodiversity
