11.5 Calculating Genetic Biodiversity Flashcards
Definition of mutation
A change in the genetic material which may affect the phenotype of an organism
Definition of natural selection
The process by which organisms best suited to their environment survive and reproduce, passing on their characteristics to their offspring through genes
Definition of genetic bottlenecks
When large numbers of a population die prior to reproducing, leading to reduced genetic biodiversity within the population
Definition of gene flow
When alleles are transferred from one population to another by interbreeding
Definition of the founder effect
When a few individuals of a species colonise a new area, their offspring initially experience a loss in genetic variation, and rare alleles can become much more common in the population
What is the link between alleles and genetic biodiversity?
The mote alleles present in a population, the more genetic biodiversity in the population
Definition of allele
Different variations of the same gene
Why is genetic biodiversity in a population important?
Species that contain greater genetic biodiversity are likely to be able to adapt to changes in the environment, and are less likely to to become extinct. This is due to some organism’s carrying an advantageous allele which enables them to survive altered conditions. If a disease was to occur, those organisms are likely to survive and therefore reproduce, leading to the survival of the species
What needs to increase for genetic biodiversity of a population to increase?
Number of alleles in a population
How can the number of alleles in a population increase?
-Mutation in the DNA of an organism, creating a new allele
-Gene flow, interbreeding between different populations which transfers alleles between the two populations
What needs to decrease for genetic biodiversity of a population to decrease?
The number of alleles present
How can the number of alleles in a population decrease?
-Selective breeding, where only a few individuals in a population are selected for their advantageous characteristics and bred
eg. pedigree animals, human food crops
-Captive breeding programmes in zoos and conservation centre, where only a small number of captive individuals of a species are available for breeding, often when a species is endangered or extinct
-Rare breeds, where selective breeding has been historically used to produce a breed of domestic animal, which then become less popular or unfashionable, so numbers of the breed fall catastrophically. Only a small number of breed remain so genetic diversity will be low
eg. Gloucester old spot pig needs to have one spot to be accepted into the registry of this breed
-Artificial cloning
eg. using cutting to clone a farmed plant
-Natural selection, overtime alleles contain less advantageous characteristics will be lost from a population
-Genetic bottlenecks, where only a few individuals in a population survive an event or change, reducing the gene pool
-Founder effect , where a small number of individuals create a new colony, the gene poll of this new population is low
-Genetic drift, the random nature of alleles being passed on from parents to offspring, the frequency of occurrence of an allele will vary
How can scientists measure genetic biodiversity?
By measuring polymorphism
What are polymorphic genes?
Genes which have more than one allele
What is meant by a gene being monomorphic?
a single allele exists for this gene, this is the case for most genes
Equation to calculate the proportion of polymorphic gene loci be measure
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 a gene on a chromosome
What is the link between the proportion of polymorphic gene loci and genetic biodiversity?
The greater the proportion of polymorphic gene loci the greater the genetic biodiversity
