Ecology - Trophic Levels & Food Production Flashcards
What is a “trophic level”?
Any level in a food chain or web.
What is the first organism in a food chain called?
What is the level above the first organism called?
What is the final organism in a food chain called?
A primary producer - as its a photosynthetic organism (producer).
A primary consumer, then secondary consumer, then tertiary consumer
The apex predator (usually a secondary or tertiary consumer).
What names would you give to the species in this food chain?
Grass = Primary producer
Zebra = Primary consumer
Lion = Secondary consumer & apex predator
What is a pyramid of biomass?
How is biomass measured?
The mass of each organism at each trophic level in a food chain. It is always a perfect pyramid.
Biomass is measured by the dry weight of organisms (after being dried in an oven) because the amount of water they contain is variable. Usually this is just an estimate as we would have to kill animals to measure.
How much energy do the plants and algae use that is transferred from the sun?
About 1%
How much energy is transferred from producers to consumers, when consumers eat the producers?
Why is so much of the biomass lost?
- About 10%
- Some is lost through solid waste (faeces), and most is lost through waste products of respiration (water and CO2)
Why are food shortages now a significant problem in the world?
Because the population of humans on earth is rising. There is not enough food to feed the entire population.
What is a monoculture farming system?
What are the problems with this?
When farms only grow one type of crop
This can lead to nutrient deficiencies in the soil and a build-up of pests
What is an alternative to monoculture farming?
Crop rotation - this is when different drops are planted each year in the same field depending on the season. This is less damaging to soil and builds up less pests.
What is intensive farming and why is it done?
Intensive farming uses modern techniques in order to maximise yields and generate more money
What are some intensive farming techniques?
- Field are quickly planted with another crop after the last one has been harvested, not allowing the ground to recover for long.
- Animals are kept in small spaces to reserve energy and maximise growth (factory farming)
- Fertilisers, herbicides and pesticides are used to enrich soils and increase the growth of crops
- Antibiotics are given in food to animals to prevent any diseases
- Machines are used to sow, treat and harvest crops in order to collect crops in shorter times
What is organic farming?
The opposite of intensive farming
- Only natural fertilisers and pesticides are used
- Manure or bone meal are spread onto field
What is one consequence of organic farming?
Because the methods of intensive farming aren’t used, yields are lower the prices are higher in shops.
Les than 1% of the world’s farmland is organic
Overfishing is becoming a big problem - what rules have been put in place to protect fisheries?
- Reducing the times are which boats can wish
- Reducing the total number of boats
- Reducing the amount of fish boats are allowed to catch (a quota)
- Using nets with larger holes to prevent catching of juvenile fish, allowing them to reproduce and restore population levels.
