Biodiversity Flashcards
Define biodiversity
Variety of living organisms in a community/habitat. It includes the species and genetic diversity
Define habitat
The place where an organism lives
Define community
The organisms of different species living in a habitat
Define species richness
The number of different species
What does the diversity of a community reflect?
Species richness
Number of organisms in a species
What can the species diversity index be used for?
Compare the species diversity of different habitats
Compare the species diversity of the same habitat over time
What does a low species diversity indicate?
Few species present suggest only few can survive harsh conditions
Populations are small
Abiotic factors determine which species are present
What does a high species diversity indicate?
Many species are present
Populations are large
Biotic factors (predation) determine which species are present
Change in one population is unlikely to affect another due to complex food webs
Why is sampling random?
To prevent bias
What does sampling aim to collect?
Data that is representative of the whole community
Method of random sampling
1) A grid is laid across the sample area using tape measures.
2) Random generator plots coordinates for quadrat
3) Each organism in the quadrat is identified and the number of each species is counted.
4) A large number of quadrats is used (20)
What is monoculture?
The growth of one type of crop by removing existing vegetation
How does monoculture reduce species diversity?
Remove other crops
Removing hedgerows (habitat)
Removing weeds
Draining marshlands
Pesticide removes insects
Fewer plant species = Fewer herbivores = fewer carnivores
Advantage of hedgerows
Habitat for predators of pests so reduce need of pesticides
Habitat for pollinating species
Disadvantages of hedgerows
Habitat for pests
Increased competition for water, light, minerals
