exam questions Flashcards
explain the importance of sampling in measuring the biodiversity of a habitat (2 marks)
- difficult to count every individual
- sample provides an estimate
- sample is representative of a whole area
explain the difference between species richness and evenness and why both are needed to assess biodiversity (3 marks)
richness = number of different species in a habitat
evenness = number of individuals of each species in a habitat
- both reveal dominance
- high biodiversity is associated with both
define ‘phylogeny’ and explain its relation to classification (3 marks)
- classification of organisms based on evolutionary relationships
- basis of classification
- based on amino acid sequence
- organisms in same group have shared phylogeny/common ancestor
outline 3 reasons of importance in conserving a species
- part of a food chain - provide food or control a population
- duty of humans to care for others/ethics
- economic/tourism
why is it sometimes necessary to conserve a species ex situ? (3 marks)
- due to climate change or human factors
- low population
- in the wild reproduction is difficult
- protect from pathogens
- maintain gene pool
give 3 advantages of storing plants as seeds
- takes up little space
- less vulnerable to disease
- more viable
outline the implications for a habitat if simpsons index is low (2 marks)
- habitat dominated by few species
- ecosystem is unstable
how can simpsons index be made more accurate? (2 marks)
- random sampling
- standardised procedure
- survey at different times
define biodiversity
- variety of species in an area
- variety of ecosystems
- variety of alleles
other than habitat destruction, identify two ways in which agriculture reduces biodiversity (2)
- pesticides kill insects
- herbicides kill plants and small animals that eat them
- production of monoculture
