B6.1 Flashcards
(31 cards)
What is biodiversity?
Variety of different species of organisms in an ecosystem. High biodiversity = more stable ecosystem.
What is a quadrat used for?
To estimate distribution and abundance of organisms in an area.
What is a transect?
Defined area where samples are taken to estimate organism numbers.
How can quadrats be placed?
Along transects or randomly across the area.
What does percentage cover measure?
Estimates how much area is covered by a species; less accurate than counting.
How can quadrat accuracy be improved?
Take more samples, repeat tests, or use larger transects.
What are nets used for?
Collecting flying insects like butterflies.
How are nets used in sampling?
Swept through long grass, insects counted, repeated across areas.
What is a pooter?
A jar with tubes to collect insects using suction.
Why is there a mesh in a pooter?
Prevents insects from being swallowed.
What are pitfall traps used for?
Sampling small insects (e.g. beetles, spiders)
How do pitfall traps work?
Container buried with smooth sides, covered with wood, insects fall in.
What is the capture-recapture method?
Insects are marked, released, and recaptured to estimate population size.
What must be assumed in capture-recapture?
No deaths, migrations, or impact of marking on visibility/survival.
Name 4 negative impacts of human land use.
Habitat destruction, species threat (hunting), pollution, deforestation.
Give 2 examples of pollution affecting ecosystems.
Sewage in water, smoke/acidic gases polluting air.
What is deforestation and why is it done?
Clearing trees for farming, biofuels, or land use.
How does deforestation increase CO₂?
Burning trees releases carbon; microbes respire CO₂ from dead plants.
Why does deforestation reduce biodiversity?
Fewer habitats and less CO₂ absorbed due to fewer trees.
Give 3 ways to preserve habitats.
Maintain rainforests, protect rare habitats, replant hedgerows.
How can deforestation be reduced?
Selective logging - only cut down once trees reach certain height. afforestation - replacing cut down trees
What is the aim of breeding programmes?
Prevent endangered species from becoming extinct.
How does recycling help ecosystems?
Reduces landfill use and use of natural resources.
List 2 benefits of maintaining biodiversity.
Prevents extinction
supports ecotourism - money to support conservation
