B9: Ecosystems And Material Cycles Flashcards
What does population mean?
All organisms of the same species living with one another in a habitat
What does community mean?
All of the populations of different species living together in a habitat
What does ecosystem mean?
Community of organisms and non-living components of an area and their interactions
What does interdependent mean?
- organisms are dependent upon each other
- a change in the population of one species can affect other populations within a community
What does mutualism mean?
The interaction between 2 organisms where both benefit as a result of their relationship
What’s a piece of apparatus that is used to measure the abundance and distribution of organisms in an area?
Quadrat
What does a food chain show?
It describes the feeding relationships between organisms and the resultant stages of biomass transfer
What does biomass mean?
The total mass of living material
What’s a simple food chain?
Producer -> primary consumer -> secondary consumer -> tertiary consumer
What’s biodiversity?
The variety of living organisms in an ecosystem
How does fish farming affect biodiversity?
- food used to feed the fish and waste can leak into water sources, causing eutrophication
- parasites from fish farms may spread and contaminate surrounding ecosystems
- other organisms may become tangled in netting
How does the use of fertilisers affect biodiversity?
Excess fertiliser can wash into water sources causing eutrophication and death of many species, reducing biodiversity
What’s eutrophication?
A type of water pollution caused by the addition of sewage or fertiliser
How can humans more positively impact biodiversity?
- conservation schemes (national parks, seed banks)
- reforestation
- protecting endangered species
What’s reforestation?
Replanting forests to help restore biodiversity
How do conservation schemes protect biodiversity?
They protect species from becoming extinct and increase population numbers
What are 3 benefits of maintaining biodiversity?
- jobs provided by ecotourism, reforestation and conservation schemes
- to discover plant species that may contain chemicals that could be used in future medicine
- reduces damage to food chains
What is food security?
Ensuring that populations have access to adequate amounts of safe and nutritious foods
What are 3 biological factors affecting food security?
- rising human population
- changing diets
- sustainability
What are the 3 types of nutrient cycle?
- carbon
- water
- nitrogen
Why are the nutrient cycles important?
They are essential to life, fixed amount of nutrients on earth which must be constantly recycled
What are the stages in the carbon cycle?
- photosynthesis
- respiration
- exchange
- sedimentation
- extraction
- combustion
What are the stages in the water cycle?
- evaporation
- transpiration
- condensation
- precipitation
- infiltration
- runoff
What is potable water and how can it be prepared?
Drinking water
- desalination
What is desalination?
A process that removes salts from saline water
What are 2 methods of desalination?
- thermal
- reverse osmosis
What do plants use to make proteins?
Nitrates
Why can’t nitrogen be used directly by plants to form proteins?
Nitrogen is un reactive
What is the role of nitrogen-fixing bacteria in the nitrogen cycle?
- convert nitrogen gas into ammonia
- ammonia dissolves in solution forming ammonium ions
Where are nitrogen-fixing bacteria found?
- soil
- root nodules of legumes
How does temperature affect the rate of decomposition?
Decomposers release enzymes
- rate highest at 50°C (optimum)
- lower temperatures, enzymes work too slowly, rate decreases
- high temperatures, enzymes denature, decomposition stops
What factors affect the rate of decomposition?
- oxygen availability
- temperature
- water content
How do decomposers break down dead matter?
Release enzymes which catalyse the breakdown of dead material into smaller molecules
What is meant by decomposition?
The breakdown of dead materials into simpler organic matter
What are the stages of the nitrogen cycle?
- nitrogen-fixation
- feeding
- production of nitrogenous waste products
- nitrification
- uptake of nitrates
- denitrification
Where are denitrifying bacteria commonly found?
Waterlogged soils
