B18 Biodiversity and ecosystems Flashcards
What is biodiversity?
A measure of the variety of all the different species of organisms on Earth, or within a particular ecosystem
How does high biodiversity help to ensure the the stability of ecosystems?
It reduces the dependence of one species on another for food and shelter
How do humans reduce the amount of land available for animals and plants?
By building, quarrying, farming and dumping waste
How do humans pollute water ways? (3)
With sewage, fertiliser and toxic chemicals
How do humans pollute the air? (2)
Smoke and gases such as sulfur dioxide - which adds to acid rain
How is the land being polluted? (5)
Sewage, farming methods, herbicide and pesticides, toxic chemicals from landfill, chemical fertiliser
How does high levels of nitrate in the water lead to the death of organisms?
- High levels of mineral ions stimulate rapid growth of algae and other water plants
- Competition for light increases and many plants die because they cannot photosynthesise
- Microorganisms feed on dead plants and the population of microorganisms increases rapidly
- Respiration by microorganisms depletes the oxygen concentration in the water
- Most aerobic organisms, like fish, die. Lack of oxygen eventually means the water cannot sustain living organisms
Why is sulfur dioxide bad? (3)
Sulfur dioxide dissolves in water in air, forming acid rain.
1. Acid rain kills animals, reducing biodiversity.
2. Acid rain can change a soils pH, which damages roots and releases toxic minerals.
3. Trees can be damaged if leaves are soaked in acid rain for long periods
What has deforestation caused? (3)
An increase in the release of carbon dioxide into the atmosphere, reduced the rate at which CO2 is removed from the atmosphere, reduced biodiversity
What does the destruction of peat bogs result in?
The release of carbon dioxide into the atmosphere becausew
What is peat used as?
Compost
Why does peat release carbon dioxide when it is burnt?
Because it contains microorganisms which release carbon dioxide through respiration
What may an increase in the Earths temperature cause? (5)
Big changes in the Earths climate, a rise in sea levels, changes in migration patterns, changes in distribution of species, reduce biodiversity
What are some environmental changes that affect the distribution of species in an ecosystem?
The availability of water, temperature and the composition of the atmosphere
Why are breeding programmes carried out?
To restore endangered species to a sustainable population
What are some of the difficulties with breeding programmes? (3)
Many rare animals and plants don’t reproduce easily or fast, need to avoid inbreeding, the habitat needed may be lost
Name something that has reduced waste
Taxing landfill
How can farmers help increase biodiversity?
By replanting hedgerows and allowing wild plants to grow on edges of fields
What is biomass?
The mass of living materials in plants and animals
What do trophic levels represent?
An organisms position in a food chain
What are apex predators?
Carnivores with no predator
What do decomposers do?
Break down dead plant and animal matter by secreting enzymes into environment. Small soluble molecules then diffuse into the microorganism
What trophic level has the largest amount of biomass?
Trophic level 1
Why does trophic level 2 have less biomass than level 1?
Because the herbivore does not eat all of the plant material and it cannot digest some of what it eats
Why is even less biomass transferred to trophic level 3 from level 2?
Because carnivores only eat parts of the herbivore (cannot eat bones etc.)
How is biomass lost? (4)
Urine, faeces, providing energy for movement and growth, energy from cellular respiration is transferred by heating up surroundings
What is food security?
Having enough food to feed a population
What are factors that affect food security? (5)
Increasing birth rates, changing diets in developed countries, new pests and pathogens, environmental changes, the cost of agricultural inputs
How can we produce meat more efficiently?
Preventing animals from moving, keeping animals in a warm shed
What policies have been put into place to stop fish stocks from declining?
Fishermen: can only remove a quota of fish per year and must use certain sized nets to avoid catching young fish
What can fermenters be used to produce?
Drugs
What fungus is grown in fermenters to produce mycoprotein?
Fusanumis
