Evolution Flashcards
Evolution definition
Evolution is the process of gradual changes in the inherited characteristics of organisms over generations as a result of genomic variations.
How is genetic material transferred?
Can be transferred by either vertical transfer or horizontal transfer
Vertical transfer -
Genes are transferred from parents down to offspring. Either as a result of sexual or asexual reproduction.
Horizontal transfer
Genes are transferred between members of the same generation - can occur in prokaryotes by transformation, transduction or conjugation.
Sexual reproduction (vertical transfer)
Involves two genetically different parents. Offspring inherit different combination of genes from each parent due to mixing of gametes.
Asexual reproduction (vertical transfer)
Reproduction from a single parent. Offspring are genetically identical to the parent, they are clones showing no variation.
How does horizontal transfer benefit prokaryotes?
Gives them the potential for much faster evolutionary change than organisms that use only vertical change
Rapid evolutionary change positives and negative ps
Positive - obtaining a gene from a neighbour is much faster than waiting for one to evolve.
Negative- no guarantee that the transferred gene will give the organism an advantage and could harm the organism
Antibiotic resistance
Horizontal transfer means that prokaryotes can pass on the plasmids carrying antibiotic resistance genes from bacteria to bacteria very quickly.
Why is genetic variation important?
To allow a population to evolve over time in response to changing environmental conditions.
Source of genetic variation?
Mutations
How can allele frequency change?
Via the process selection-
Process by which the frequency of alleles in a population increases or decreases in a non random way. This means there is selection for or against a particular characteristic.
