What is a term used to describe the relationships between the members of a community in an ecosystem?
Food Chain or Food Web
What is each stage in a food chain known as?
A trophic level
What do food chains typically start with?
Photosynthetic producers because they extract energy and matter from the sun and other abiotic environmental factors
What are the 3 kinds of ecological pyramids?
- Numbers
- Biomass
- Energy
What shape are pyramids of numbers?
Can be any shape depending on the size of the organism on each trophic level. Traingle, inverted triangle, middle widest, etc.
What is biomass?
The dry mass of an organism
What shape are pyramids of biomass?
Typically pyramid/triangle shaped. Usually cannot be inverted because you can’t weigh more than you eat, but sometimes inverted in aquatic ecosystems for a certain month where growth is rapid and seasonal
How much biomass is typically passed from one trophic level to the next?
10%
Why is energy/matter lost as you go up the trophic levels?
- Matter is lost as CO2 from Respiration
- Uneaten or indigestible parts
- Waste, e.g. Faeces and Urine
- Movement
- Thermogenesis
What are pyramids of energy?
Pyramids which represent the flow of energy in a given time. They are always very shallow since energy transfer between trophic levels is very inefficient (typically 1%)
Compare and contrast Matter and Energy (4 Points)
- Matter is kilograms, Energy is joules
- Matter is 3 states, solid, liquid or gas. Energy comes in many forms
- Neither energy or matter can be destroyed
- Level of Matter on Earth is constant, Energy is ‘roughly’ constant but can enter and leave
Why are food chains so short?
They tend to be 3-4 levels because too much energy is lost at each stage to sustain more levels, which is why there are fewer at the top than bottom
Why is it more energy efficient to be vegetarian
Plants are lower on the food chain so less energy is lost in the making of it than meat which loses energy at multiple stages
What is bio-accumulation?
The accumulation of substances such as pesticides in an organism, which occurs when an organism absorbs a toxic substance at a higher rate than at which it is lost
How is energy lost going from the sun to producers?
- Light passes through the leaves and misses the chloroplasts
- Light is reflected off the leaves
- Light is reflected by atmosphere and clouds
- Limiting factors of photosyntheiss
What percentage of light energy of light energy becomes biomass in producers?
2%
What are the advantages of intensive farming?
- Cheaper food because higher yield
- Higher yield for less space
- Selective breeding for higher productivity
- Selected diet
- Less Movement, Warmer and Safe from Predators
What are the disadvantages of intensive farming?
- Quality of food
- Spread of Disease
- Antibiotic resistance
- Cruel to Animals
- Potential overheating
Pros and cons of herbicides to improve farming productivity
Kills weeds stealing minerals from the main crop but reduces species diversity
Pros and cons of pesticides to improve farming productivity
Decreases loss of crop due to pests, increases productivity but upsets the food chain involving the pests
Pros and cons of using larger fields to improve farming productivity
Removing non productive things like hedgerows means more crop per unit land, but removes habitats in hedgerows
Pros and cons of selective breeding?
Increases productivity, but decreases genetic diversity so less likely to survive change in environment
Pros and cons of monoculture
increases productivity but allows pests to spread easily
List things that can be done to improve farm productivity
- Fertilisers
- Herbicides
- Pesticides
- Large Fields
- Mechanisation
- Selective Breeding
- Green House
- Monoculture
