evolution Flashcards
what did old evidence for evolution rely on
similarities in the apperance of living organisms and on fossil evidence
problem with relying on morphology for understanding evolution
two species can look similar because they evolved to respond to similar niches
what determines how long common ancestry there has been
the more mutations in the DNA in two species- longer theyve had common ancestor
how to determine how long common ancestor lived
using an agreed mutation rate as a molecular clock
problems with looking at DNA to see evolution
DNA degrades quickly and rate at which different parts of DNA mutate varies
why is human evolution hard to follow
because of lack of fossils
method of analysing DNA
PCR test
what does the polymerase chain reaction do
amplifies minute samples of DNA and DNA profiling
how many parasitic lice do humans have
head
pubic
body
what do scientists do with evidence form DNA analysis
build diagrams that model the evolution of species from a common ancestor
molecular phylogeny
the analysis of DNA to identify the inter relationship between different groups of organisms
how is DNA used to make links between organisms
patterns in DNA identified
comparisons between amino acid sequences of similar proteins in different species
gel electrophoresis
variation of chromatography which can be used to separate DNA and RNA fragments proteins of amino acids
what does gel E seperate substances by
their charge and size
where are the substances being compared placed in gel E
in wells of gel medium in a buffering solution with known DNA to aid identification
when identifying DNA what cuts the DNA molecules in gel E
restriction endonucleases
function of restriction endonucleases
cuts DNA into fragments at specific sites
what are the DNA fragments added to in gel E
to gel that had dye which binds to fragments in gel and fluorsecent under UV light
why is dye also added to DNA samples
doesnt bind to DNA but moves gel faster than DNA so current be turned off before all samples run off at end
how do DNA fragments move in gel E
move to positive anode because of negative charge, move at different rates because of charge and mass.
step after gel E complete
plate placed under UV light. DNA fluoreses and show pattern of movement
what is added instead of gel when comparing amino acids in gel E
ninhydrin reacts with amino acids so they can show as purple patches and compared with known amino acids for identification
ways to identify biochemical relations
analysis of blood pigments
analysis of sequences of amino acids
endosymbiosis
two organisms adapted to live together that benefit each other
