3.4.6 Biodiversity Within a Community Flashcards
(18 cards)
What is a community?
all the organisms of all the different species living in a habitat
The greater the diversity….
the more stable an ecosystem
Why does high diversity make an ecosystem more stable?
higher likelihood of species being able to tolerate changes in environment
What is species diversity?
number of different species and the number of individuals of each species within a community
What is ecosystem diversity?
the range of different habitats within a particular area
What is genetic diversity?
variety of alleles possessed by individuals that make up one species
Give 3 threats to biodiversity
-pollution
-climate change
-habitat destruction
Why do we need to measure biodiversity?
-compare diversity of same habitats over time
-compare diversity of 2 different habitats at the same time
-to see if conservation work is having a positive effect
What is species richness?
number of species found in a habitat
more species = richer habitat
What is species eveness?
number of individuals in each species (abundance)
What is the Simpsons Diversity Index?
d = N(N-1) / sum of n(n-1)
N: total number of organisms of all species
n: total number of organisms of each species
d: index of diversity
What does a low value of d suggest?
less diverse - more likely to be dominated by 1 species
Direct reduction of diversity as a result of agriculture
-overgrazing (decreases size of plants)
-creating monocultures (reduces anima and species diversity due to limited food sources)
-removing hedgerows (reduces habitat)
Indirection reduction of diversity as a result of agriculture
pesticides/ fertilisers - eutrophication if in run off water, can kill a wide range of animals
What is conservation?
act of protecting and managing species and habitats (in a sustainable way)
Give 3 conservation techniques in rainforests
-sustainable logging
-afforestation
-ecotourism
Give 4 conservation techniques using in agriculture
-biological control (natural predators to control pests)
-natural fertilisers
-pond creation (increases habitat variety)
-hedgerow planting (increases diversity)
What is the struggle of biodiversity vs profit?
-increasing biodiversity if time intensive and expensive
-increasing biodiversity can reduce yield of crops (and hence profits)
solution: money grants to encourage farmers
