Biology 4 Flashcards
Compare the biodiversity of natural and artificial ecosystems. Include examples of each type. (4)
Natural ecosystems (e.g. native woodlands and lakes) (2) have a higher biodiversity than artificial ecosystems (e.g. forest plantations and fish farms). These have been around for less time and use pesticides as they have a purpose (2).
Explain how natural ecosystems are self-supporting, apart from having an energy source. (4)
Plants depend on animals for pollination/minerals from decay (1).
Animals depend on plants for energy from food (1).
Plants produce oxygen which animals use for respiration (1).
Animals produce carbon dioxide which plants use for photosynthesis (1).
What was Priestley’s important contribution to the understanding of photosynthesis? (1)
Plants produce oxygen from photosynthesis (1).
Explain how isotopes have changed our understanding of photosynthesis. (3)
The isotope oxygen-18 was used (1) to prove that oxygen gas was produced by the splitting of water to make oxygen and hydrogen ions (1) - and not carbon dioxide (1).
What do you understand by the term ‘absorption spectrum’? (1)
Parts of the light spectrum used in photosynthesis (1).
Explain how diffusion occurs. (2)
Diffusion is the net movement of particles from an area of high to low concentration (1) due to the random movement of particles (1).
What are the possible consequences of plasmolysis in plant cells? (2)
Plant cells collapse (1) causing the plant to wilt (1).
Describe how xylem vessels are different to phloem vessels. (3)
Xylem vessels are made of dead not living cells (1). They have a hollow lumen (1) and thicker cell wall (1).
How can you tell that a leaf have been left in dark conditions? (2)
Most of its stomata are closed as there is no light so photosynthesis does not occur (1). This happens to prevent water loss (1).
Explain how a plant can change its stomatal apertures. (3)
Guard cells absorb water by osmosis (1) causing them to become turgid (1) and curve open (1).
How does active transport differ from diffusion? (3)
Active transport requires energy from respiration (1). It moves substances against the concentration gradient (1) using carrier molecules (1).
Name three useful animals in a compost heap. (3)
Earthworms (1)
Maggots (1)
Woodlice (1)
Suggest different views of having a compost heap. (4)
Advantages - Avoids filling landfill sites (1) and recycles minerals to make natural fertiliser (1).
Disadvantages - Unsightly/Smelly (1) and needs space in the garden (1).
Suggest why biological control is thought to be better than insecticides. (3)
Insecticides can accumulate in the food chain (1) and cause harm to useful organisms (1). Some insecticides are persistent (1).
Some farmers use a crop rotation system. Explain why. (3)
To grow food organically (1) and maintain soil fertility (1). It avoids the build up of pests in one area (1).
