biodiversity (CMO) Flashcards
what is a selection pressure
they are environmental pressures which effect the chance of survival e.g. resource availability
what is stabilizing selection
relatively constant change over generations
what is directional selection
gradual change over generations
natural selection in which alleles change over time, this typically occurs in environments where change in environment occur e.g. Darwin’s finches
what is disruption selection
maintain high frequency of two different alleles
occurs within any population e.g. Darwins finches
for: both extremes
against: moderate traits
what is natural selection
the theory that organisms with advantageous traits survive and reproduce thus passing the trait to the offspring
what is biodiversity
it is the variation between all forms of life
why is biodiversity important
it allows ecosystems to be resilient to change within the environment
what is an ecosystem / habitat diversity
it is the range of different ecosystems within a region
larger habitat frequency = higher biodiversity
what is an example of a region with high biodiversity
the coral reef
has high frequency of species and individual species within communities
what is an example of a region with low biodiversity
the desert
species Widley dispersed and have harsh conditions
what is species rich
a species with a high frequency
why is maintaining biodiversity important
morally
stability of ecosystems
environmental
economic
aesthetic
agriculturally
what is the index diversity equation
d= N(N-1)
———-
En (n-1)
what is genetic diversity
it is the different number of alleles in genes
what is genetic isolationism
when two groups are isolated so become genetically isolated, as they no longer interbreed / exchange genetics so evolve independently
what is comparing characteristics
it is quick but mot very reliable e.g. comparing features like fur
what are measurable characteristics
features we can analyse and measure e.g. DNA analysis
how do we compare nucleotides
DNA is extracted from nuclei of organism can be blood or fossil /skin
DNA is then processed, base sequence compared
more similar = closer related
mitochondria DNA analysis
analyse DNA from mitochondria
zygote only contain mitochondria from maternal egg cell
no crossover mean mutation
e.g. mitochondria eve
MRNA analysis
located in cytoplasm easier to use than DNA. this is used to produce CDNA which contain the coding region of gene. compare this using universal protein cytochrome C.
amino acid comparison
amino acid easy to isolate from cell
the AA sequence is compared. protein must be the same e.g. haemoglobin
similar sequence = similar species
how have humans impacted biodiversity
as the population increase this led to an increase in:
mass extinction
climate change
competition for resources
introduction of new species
hunting
loss of habitat
what are traditional crops
sown in spring
gap between harvesting 5-6 months
what are modern crops
sown in autumn
gap between ploughing and harvesting 1-2 weeks , this leaves little time for birds to get food. if no foot available biodiversity of birds declines
what is organic farming
farming that involves no harmful chemicals or pesticides reduces the amount of insects and animals ingesting harmful chemicals
what impact are bees having on diversity
bees pollinate crops but there population is rapidly declining. the species are facing extinction
extensive farming and monoculture reduces biodiversity
pesticide also affect the population
why do farmers use pesticides
farms are not economically friendly as it is costly to run environmentally friendly
higher yield with ,modern farming
what is inerspecific variation
this refers to the vast genetic diversity between individuals from different species
what is intraspecific variation
this refers to variation within species
what are the benefits of random sampling
ensure there is no bias
reduces chance
we can lower the risk of bias by increasing sample size
what are anatomical adaptations
physical features e.g. long necks on giraffe
hairy frogs bones in feet break and bones are used as weapons. tissue heals and regenerates
what are physiological adaptations
internal body adaptions which help organisms to survive e.g. komodo dragons
have high levels of bacteria in mouth
when bite prey they die of infection
what are behavioural adaptations
can be passed on from parent or learnt at a very young age
if behaviour beneficial more likely to survive and pass advantageous behaviour on to kid
e.g. Christmas island crabs
what is genetic drift
a change in allele frequency due to chance, this can cause extinction of gene variants so lowering gene pool. could cause rare alleles to become prominent
what is a genetic bottleneck
a catastrophic event that occur resulting in a population size to reduce by 50%
what is a founder effect
occurs when a few individuals become isolated from a population
the new population will become the founders
what is speciation
it is the formation of new species from an existing species
what is allopatric speciation
this is a result of geographic isolationism this occurs when population is geographically isolated e.g. lakes, motorways
the population cannot exchange genetics
different selective pressure or genetic drift result in the evolution of a new species
what is sympatric speciation
occurs with no geographic barrier, they live within the same environment but no gene flow between them
ecological separation when species start to adapt living in same environment
the adaption occurs over generations and can result in new species
