Topic 3.3 Biodiversity Flashcards
not in summer exams L6
What is biodiversity?
The variety of organisms in an ecosystem
variety of life
( short is bd )
How to measure biodiversity?
- species richness
- relative species abundance/species evenness
What is species richness?
number of species in an area
what is relative species abundance?
relative number of species in an area
how to use the Simpson’s diversity index (D) to measure biodiversity?
D= N×(N - 1) / Σn×(n - 1)
N=total num of organisms of all species in a community
n=total num of organisms of each individual species
What does the Simpson diversity index mean?
Higher index = greater diversity
what is a disad of diversity index?
- can only be used wen comparing 2 environments
- No limit so hard to comment on diversity with 1 value
How can ecosystems be more diverse?
if each species in ecosystem is genetically diverse
why is a larger gene pool better for the species?
increased variation allows greater chance of survival if selection pressure changes
how can a species be more genetically diverse?
- increase gene pool
- mutations increase gene pool, if advantageous, gene is passed on and increases population freq
what is the biodiversity within a habitat vs within a species?
within a habitat: species richness and evenness
within a species: genetic variation
what are the acts of agriculture on biodiversity?
- destroy species habitat (reduction of hedgerows from soil erosion)
- use of pesticides
- monocultures grown
- increase land used for growing crops
what is the result / impact of biodiversity from agriculture?
fewer habitats and niches
reducing stability of food chain
3 reasons why biodiversity is important? (3 Es)
- ecological
- ethical
- economic
why is it good to have rich biodiversity?
- allow ecosystems to function and self-regulate
they are interlinked on a global scale - cope with selective pressures
what is an ecosystem service?
service provided by natural environment that benefits people