Molecular Evolution Flashcards
(48 cards)
What is creationism?
Idea that species are made by a supernatural creator
What does science assume for everything?
That there are natural explanations for everything.
What is the basis of scientific theory?
Predicts must be tested and confirmed/ refuted with data
What is Darwin’s Theory of evolution by natural selection?
Spontaneous natural variation occurs and they are stably inherited
What evidence is there for Darwin’s TOEBNS?
Man and apes descend from a common ancestor, so there must be intermediate fossils present (which there are + early homo-sapiens have been found too)
What is the modern synthesis?
Darwin’s theory and mendelian genetics are linked
Is Darwin’s theory a hypothesis?
No it is a knowledgeable deduction based on evidence
What is variation?
Mutation - change in DNA sequence
What is the common cause of mutations occurring? How common are mutations?
Mistakes during DNA synthesis although this is rare since DNA synthesis is accurate (DNA polymerase’s proof reading means it goes back and corrects mistakes)
What type of mutations are most of them?
Neutral or harmful; only some are beneficial
What are individuals in competition with?
Predators, prey and individuals of their own species
What is the effect of new alleles on reproductive success?
They can increase/ decrease it
What is relative fitness (w)? What is it compared with?
The average number of surviving offspring of a particular genotype after one generation
It is compared with competing genotypes
What does w<1 indicate?
That the frequency of the allele will decrease with each generation until the allele disappears (strong negative selection)
What does w>1 indicate?
That the frequency of the allele will increase with each generation until the allele reaches fixation (only allele left since the other alleles have been misplaced) (strong positive selection for an allele = fixation)
Does fixation realistically occur?
No - instead you get a mixture of multiple alleles
What are 3 types of small mutation?
Base substitutions and small insertions/ deletions
What are 4 types of large mutation?
- Insertion of transposable elements (parts of genome that cut out of one place and insert into another) / viral insertions (retroviruses that are then stably inherited)
- Large DNA duplications
- Large deletions
- Chromosome rearrangements
What would be a difference between species with a more recent common ancestor vs. species with a more distant common ancestor?
Species with a more recent common ancestor have fewer differences in their DNA sequences (since there has been less time to allow for DNA mutations to occur in their sequences)
What are antibiotics?
Substances that are toxic to bacteria but not fungi (they are produced from fungi)
Why our fungi humans cousins?
They are closely related to humans than plants
What can DNA sequence data of animals be used for?
To generate family trees
How was HIV theorised to be introduced into the human population?
A contaminated batch of polio vaccine (which was grown on culture monkey cells)
When comparing sequences of 2 species why are there more differences found in introns than exons?
Introns are not protein coding sequences of DNA, but exons are. If a mutation occurs in an exon it is more likely to mess up a protein so is removed by negative selection where as introns are less important to remove
