lecture 22 Flashcards
what is hierarchial system of classifications and how does it relate to evolution?
kindom → phyla → classes → orders → families → genera → species
this was before darwin/evolutionary framework was created, however framework is suited for evolutionary approach by common descent/ancestry
further up hierarchy, farther back in time to reach for a common ancestor, whill all in same family may have more recent common ancestor
why is precise biological classification important?
precise name is important for communication/literature
ex. need to know what species of oak tree we are gather data on, w/o precise name to asosciate w/ data its difficult for others to understand
precise names create predicitve power
by knowing specific genus of an oak tree, it can be predicted that the data collected from the oak tree shld be closely related to other species in same genus than diff genus
the name allows us to understand origin, evolutionary history, ecology, geopgraphy of species
what is taxanomy?
taxonomy is the naming and classifying of things, ascribing a label to each part of the biological units
how are taxonomy and systematics related?w
taxonomy naming reflects systematics, based on genus and other relationships
systematics need taxonomy to label things so we know what we are talking abt
what are derived characters?
derived character are character which evolved subsequent to a common ancestor after a speciation event
can be changes in sequence level to genes/genomes, changes to sequence of letters, structure, copy number, chromosombe number
can also be external phenotypes which have evolved
why are derived characters studied?
can be read backwards in time which helps understand history of life, as well as categorize which species are more closely related than others
helps understand large-scale evolution patterns which can only be seen when looking above species level
helps understand traits, and how many times they’ve evolved/under what conditions are similar traits evolved
helps understand microevolution/spliting of strains and lineages of damaging parasites
what are monophyletic groups?
complete set of species derived from a common ancestor, usually the goal of phylogenetic trees is to make inferences abt these groups
a single ancestor gave rise to all species in taxon and no species in any other taxon
why are monophyletic groups studied?
they give the strongest degree of inference abt a particular group of species, all ancestry/evolutionary history is considered
what are paraphyletic groups?
paraphyletic groups, contain some but not all species derived from common ancestor
what is a clade?
a clade is a related group of organsims from an immediate common ancestor
what do paraphyletic groups create and what does this mean?
they create articial grouping which don’t represent complete evolutionary history
what is an example of an artificial grouping?
ex. reptiles are artifical groupings, ignores birds
whatever ancestor gave rise to turtles, snakes, lizards also gave rise to birds but birds aren’t included in reptiles which makes it a paraphyletic group
what are ancestral traits?
ancestral trait are traits shared w/ common ancestor
what is homology?
the similarity of traits due to shared ancestry, similar features reflects common descent/shared ancestry
what is homoplasy?
homoplasy is the similarity of traits resulting from convergent evolution
evolution of same/similar phenotypes from diff backgrounds, ancestry which means that there is no actual natural relatedness, although it appears there is
