B2 Flashcards
Describe how carbon is recycled in the sea.
- Marine organism shells are made of carbonates. The shells drop to the sea bed as the organisms die
- The shells fossilise to become limestone rock
- Volcanic eruptions heat the limestone and release carbon dioxide into to the atmosphere. Carbon dioxide is also released during the weathering of limestone rock.
- Oceans that absorb carbon dioxide are know as ‘carbon sinks’.
Describe the stages of the carbon cycle.
- Carbon dioxide is removed from the atmosphere by green plants for photosynthesis
- Plants and animals respire, releasing carbon dioxide into the atmosphere
- Soil bacteria and fungi (decomposers) feed on dead plants and animals, causing em to break down, decays and releases carbon dioxide into the air. (The microorganisms respire as they feed passing the carbon compounds along the food chain). This decay process makes elements available to living organisms.
Why is nitrogen such a vital element?
- It is crucial in the production of proteins which are needed for growth in plants and animals
- A lot of nitrogen is stored in the air, however animals can’t use this as it is so unreactive
Describe the nitrogen cycle.
- Plants absorb nitrates from the soil to make proteins for growth
- Animals eats plants and use nitrogen to make animal protein. feeding passes nitrogen compounds along the food chain
- Dead animals and plants are broken down by decomposers, releasing nitrates back into the soil.
Why might waterlogged or acidic soil slow down the rate of recycling nutrients?
- Waterlogged soils lack oxygen for decomposers
* Acidic soil is not an ideal pH for decomposers
What do animals compete for?
- food
- water
- shelter
- mates
What do plan plants compete for?
- light
- water
- minerals
What is interspecific competition?
• Interspecific competition is where individuals of different species compete for the same resources in a ecosystem such as food or space
What is intraspecific competition?
- Intraspecific competition is where individuals from the same species are competing for the same resource.
- This is far more significant as it is the same species competing for the same thing
Explain the term ‘ecological niche’
• Similar organisms living in the same habitat will have the same prey and nesting sites - they occupy the same ecological niche • same place + function For example: • different ladybird species • red and grey squirrels
What is a cyclic fluctuation?
• A fluctuation (a changing amount) in the numbers of species related to each other -prey and predator.
• This hoes round in cycles e.g.
-As the predator becomes stronger there is less prey to round
-Then there isn’t enough prey to go round
-The predator’s decrease
-The prey’s increase
Describe and give an example of a parasitic relationship.
- Where organisms survive by living off other organisms - known as parasites.
- The organism they live from is know as the host
Describe and give an example of a mutualistic relationship.
- In mutualistic relationships, two organisms from a relationship from which both organisms benefit.
- For example, leguminous plants such as the pea and bacteria have a mutualistic relationship. Bacteria in the root nodules take sugars from the plants to use in respiration. They also, in return, convert nitrogen into nitrates, which benefits the plant as it is able to survive in nitrogen poor soils. So the bacteria gains sugars and the plant gains nitrates.
Summarise Lamarck’s theory of evolution.
• Lamarck suggested that evolution happened by the inheritance of acquired characteristics
1. Organisms change during their lifetime as they struggle to survive
2. These changes are passed on to their offspring
• No genetic evidence to suggest this was the case
