Lecture 7: Phylogenetic Trees: The Diversity of Life Flashcards
(8 cards)
what are the taxonomic groups of the hierarchical classification of life?
from broad to narrow:
domain, kingdom, phyium, class, order, family, genus, species
what are the principles behind the hierarchical classification of life?
two-part scientific name of a species is a ‘binomial’
the first part of the name is the ‘genus’
the second part is the ‘epithet’ and is unique
first letter of genus capitalised
entire species name italicised or underlines
what is the difference between homology and analogy?
homology is similarity caused by shared ancestry, like between a wolf and dog
analogy is similarity causes by convergent evolution, similar conditions/ adaptions
what is a monophyletic group?
group of organisms that includes a common ancestor and all of its descendants
how is DNA used to build phylogenetic trees?
lengths of branches can show the number of genetic changes taken place in a particular DNA sequence
systematists look for genetic differences in segments of DNA as a greater number of differences usually implies greater evolutionary distance
what are 2 different types of horizontal gene transfer and why do they make building phylogenetic trees difficult?
transformation- DNA taken up from environment
transduction- DNA transferred into microbe through an agent such as a virus
complicates as introduces incongruence between gene trees, making it difficult to reconstruct a single tree
how can phylogenetic trees be used to test hypothesis and give an example
phylogenetic bracketing allows us to predict features of an ancestor from features of its descendants
used to infer features of dinosaurs from their descendants of birds and crocodiles
what are the hypothetical implications of these ideas for the search of life elsewhere?
shape how we search for and recognise life elsewhere in the universe
we see life can evolve from a single origin into vast complexity, so to keep this idea in mind when searching elsewhere
