4.2.1 Biodiversity Flashcards
ecosystem
all members of all species + their environment
(abiotic factors)
ecosystems with high biodiversity
rainforests
woodlands
coral reefs
ecosystems with low biodiversity
desert
tundra
habitat
a place where organisms live
community
multiple species and their interactions in an ecosystem
species
a group of organisms which can interbreed to produce fertile offspring
population
all members of the same species living in a habitat
variation
differences due to genes and environment
intraspecific variation
differences within a species
interspecific variation
differences between species
three strands of biodiversity
ecosystem diversity
species diversity
genetic diversity
species that lack genetic diversity due to isolation or low population numbers are more vulnerable to fluctuation due to what factors?
climate change
disease
habitat fragmentation
what do coral reefs provide to organisms within the ecosystem
microhabitats
shelters
breeding grounds/nesting sites
keystone organism
many others depend on for survival
have a disproportionate effect on other species
three levels of biodiversity
range of habitats/microhabitats in an ecosystem
range of species within each ecosystem
range of genes/alleles within each species
ex situ
out of natural habitat
in situ
in natural habitat
ecosystem/habitat biodiversity
the variety of ecosystems in an area
the variety of habitats within an ecosystem
species biodiversity
the variety of species within an ecosystem or habitat
2 levels of species biodiversity
species richness
species evenness
species richness
the number of different species in an ecosystem
species evenness
the relative number of individuals of each species
genetic biodiversity
the variety of genes in a gene pool for a particular species
a gene
a sequence of DNA bases that codes for a specific amino acid sequence
what determines genetic diversity
variety and frequency of different alleles in a population
methods to calculate genetic diversity
proportion of polymorphic genes
proportion of heterozygous genes
proportion of genes that are homozygous recessive
proportion of polymorphic genes =
number of polymorphic genes/ number of genes studied
factors affecting biodiversity
deforestation
destruction of coral reefs
destruction of the sea bed
overexploitation
overhunting
agriculture
pollution from agriculture
climate change
causes of deforestation
clearing for; agriculture, housing, timber
effects of deforestation
loss of species and loss of resources to rebuild number of species
habitat destruction
decreases species diversity
causes of destruction of coral reefs
farming, fishing, leisure activity
effects of destruction of coral reefs
loss of species and loss of resources to rebuild number of species
habitat destruction
decreases species diversity
causes of destruction of the sea bed
dragnets scrape the sea bed
effects of destruction of the sea bed
loss of species and loss of resources to rebuild number of species
habitat destruction
decreases species diversity
causes of overexploitation
removal of timber for industry or furniture; overfishing so fish stock falls
effects of overexploitation
reduction in the number of species and loss of habitat
causes of overhunting
removal of wild animals as ‘bush meat’
effects of overhunting
species at risk of extinction - genetic bottlenecks
causes of agriculture
monoculture of one type of crop or livestock
effects of agriculture
reduction in the number of a particular species - reduces species evenness
causes of pollution from agriculture
waste; use of fertilisers and pesticides - bioaccumulation
effects of pollution from agriculture
loss of species diversity as some species thrive with additional fertilisers and others are destroyed; runoff pollutes streams and pond water
causes of climate change
modification of weather patterns such as drought and floods affecting species distribution
effects of climate change
distribution of species change; lack of food for some species causes decline
sampling
taking measurements of a limited number of individuals in a particular area
used to estimate the number/frequency/density of organisms in an area without having to count them
how to measure species richness
count the number of different species present
how to measure species evenness
count the number of different species present and the number of individuals of each species
