evolutionary relationships Flashcards
what is the taximony ranking?
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species. DKPCOFGS. dont kiss perrys coat or feril gets sad
what is a node?
it is a branching point
what is the root?
common ancestor of all species included in the tree
what is a clade?
node with all the branches, branchlets and twigs
what are sister clades?
two clades emerging from node
what is anagenesis?
gradual phyletic change (slow accumulation of evolutionary changes)
what is cladogenesis?
ancestral specie undergoing speciation resulting in two distinct species from their common ancestor
what is homolgy?
similarity that results from shared ancestry
what is convergence?
organism evolves and analogous structures despite being unrelated
what is homoplasy?
phenotypic similarities that evolved independently in different lineages
what are the pros in using molecular data to construct phylogeny? (e.g dna sequence)
provides abundant data: every base in a nucleic acid can serve as a separate character for analysis. can be compared between distantly related organisms that share no organismal characteristics or those with only minor morphological differences
what are the cons in using molecular data to construct phylogeny? (e.g dna sequence)
because of the limited number of character states (4 nucleotide bases), researches may find it difficult to assess homology of a nucleotide base substitution that appears at the same position in the DNA of two or more species. and also because of molecular characteristics have no embryonic development, biologists have difficulty determining homology
what are the character states in relation to phylogeny? and what is the relation between the two character states?
ancestral and derived. ancestral is the character state that leads to derived character state. for example ancient fish had fins and their descendants, the tetrapod have limbs.
why do some historically recognized taxonomic groupings do not correspond to evolutionary teachings?
linnaeus system was based off of similar traits rather than origins - time before Darwin so the general belief was that animals were of God’s creation
what is the molecular clock?
indexing time at which 2 species diverged using the dna sequences.
