4.2.1 e calculating genetic biodiversity Flashcards
why is maintaining genetic biodiversity essential to the survival of a species?
genetic biodiversity is reduced why means individuals may suffer from a range of problems associated with in-breeding
why do scientists calculate the genetic biodiversity of a species?
to monitor the health of the population and ensure it’s long-term survival
why do individuals have very little variation within their DNA in a species?
because all members share the same genes
define alleles
different version of genes
what does the difference in the alleles among individuals in a species do?
creates genetic biodiversity within a species
why is it good for a species to have greater genetic biodiversity?
species is more likely to be able to adapt to changes in their environment and so are less likely to become extinct
what are the factors that affect genetic biodiversity?
mutations in DNA
interbreeding between different populations
selective breeding
captive breeding
rare breeds
artificial cloning
natural selection
genetic bottlenecks
founder effect
genetic drift
define gene flow
when an individual migrates from one population and breeds with a member of another population so alleles are transferred between two populations
what is selective breeding and what does it do to genetic biodiversity?
it is when a few individuals within a population are selected for their advantageous characteristics and bred
it reduces genetic biodiversity
what is captive breeding and what does it do to genetic biodiversity?
happens in zoos and conservation centres
a small number of captive individuals of a species are available for breeding
often the wild population is endangered or extinct
reduces genetic biodiversity
what are rare breeds and what does it do to genetic biodiversity?
selective breeding has been used to produce a breed of domestic animal or plant with characteristics which then become less popular so the numbers of the breed fall catastrophically
when only a small number pf individuals of a breed remain and are available for breeding and all of these animals will have been selected for the specific breed traits, the genetic diversity of the remaining population will be low
this can cause serious problems when trying to restore numbers yet maintain breed characteristics
reduces biodiversity
what is natural selection and what does it do to genetic biodiversity?
species will evolve to contain primarily the alleles which code for advantageous characteristics so over time alleles coding for less advantageous characteristics will be lost from a population
reduces genetic biodiversity
what is a genetic bottleneck and what does it do to genetic biodiversity?
where few individuals within a population survive an event or change that reduces the gene pool
only alleles of surviving members of the population are available to be passed on to offspring
reduces biodiversity
what is the founder effect and what does it do to genetic biodiversity?
where a small number of individuals create a new colony, geographically isolated from the original
the gene pool for this new population is small
reduces genetic biodiversity
what is genetic drift and what does it do to genetic biodiversity?
due to the random nature of alleles being passed on from parents to their offspring, the frequency of occurrence of an allele will vary
sometimes the existence of a particular allele can disappear from a population altogether
genetic drift is more pronounced in populations with a low genetic biodiversity
how is genetic biodiversity measured?
by measuring polymorphism
what are polymorphic genes?
have more than on allele
what are monomorphic genes?
a single allele exists for this gene
how can the proportion of genes that are polymorphic be measured?
proportion of polymorphic gene loci = number of polymorphic gene loci/ total number of loci
what does the locus of a gene refer to?
the position of the gene on a chromosome
the greater the proportion of polymorphic gene…
the greater the genetic biodiversity within the population
