11.5 Genetic biodiversity Flashcards
what creates genetic diversity in a species?
the differences in alleles between organisms
why does greater genetic diversity lead to greater chance of survival?
organisms with an advantageous allele are more likely as there is so much variety in the alleles in a population
less chance of a disease killing an entire population off as many will be resistant through an advantageous allele and thus survive to reproduce
how can the number of alleles in a population increase?
mutations
gene flow
sexual reproduction
mutations
mutation in the DNA will lead to different base sequence which leads to new types of gene being expressed (allele)
gene flow
species migrate and interbreed which leads to new allele combinations in offspring
sexual reproduction
meiosis:
- crossing over in P1
- independent assortment in M1,2
random fertilisation of gametes
how can the number of alleles in a population be reduced?
selective breeding
captive breeding
artificial cloning
natural selection
genetic drift
selective breeding
breeding of select individuals with desired characteristics
leads to advantageous alleles being passed on
reduces allele frequency
captive breeding
population is removed from natural environment to be conserved
reduces the population size and so reduces the allele frequency
artificial cloning
reduces the allele frequency as only one allele combination of cloned
genetic bottleneck
random chance event causes population to decrease
leads to smaller gene pool and so a smaller allele frequency as only alleles of surviving population are passed
founder effect
isolation of a small groups means smaller population so small gene pool
how can genetic biodiversity be measured?
proportion of polymorphic gene loci
what is a polymorphic gene?
a gene with more than one allele
equation of proportion of polymorphic gene loci
