Energy and Ecosystems Flashcards
What is an ecosystem?
Abiotic and biotic factors
How can biomass measured?
- Dry mass of tissue per unit area
- Mass of carbon
How to measure dry mass?
- A sample is dried (oven) at low temp. The sample is continuously weighed at regular intervals until it becomes constant
What is the mass of carbon?
About half the mass of dry mass
What is Gross primary production?
- The total amount of chemical energy converted from light by plants in a given area
What is respiratory loss?
- Heat lost to the environment when plants respire
What is Net primary production?
- Energy available to the plant for growth and reproduction, stored in the biomass
- The energy available to organisms at the next stage in the food chain
The equation for NPP
NPP = GPP - R
Equation for net production
N = I - (F + R) N = Net production I = Chemical energy in ingested food F = Chemical energy lost in faeces R = Energy lost through respiration
How to maximise energy transfer ?
- Simplifying food webs
- Reducing respiratory loss
What is biomass?
The chemical energy store for an organism
What is primary productivity?
- Rate of primary production by green plants
What is secondary productivity?
- Rate of secondary production by consumers
How can you maximise primary productivity
- Maximise light exposure
- Using warmer temps in glasshouses
- Irrigation to maximise water supply
How do fertilisers improve primary productivity?
Maintain nutrient levels in the soil as they help plants convert energy to biomass efficiently
How do pesticides improve primary primary productivity
- Remove pests that destroy crop
- Prevents loss in biomass
- Herbicides kill weeds to reduce competition
- Fungicides prevent fungal diseases
How to improve secondary productivity?
- Limit movement of animals
- Use heating barns
- Antibiotics, prevents energy loss to pathogens
