evolution- the tree of life Flashcards
(40 cards)
Linnaean classification based on
morphological similarity –> hierarchical system independent of evolutionary theory
linnaean classification makes no assumption of
relatedness
how to reconstruct evolutionary relationships
related organisms grouped, unrelated not grouped –> based on phenotype and genotype
phenotype
morphology often very informative of relationship
homologs
a gene related to a second gene by descent
orthologs
genes in diff species that evolved from a common ancestral gene by speciation and kept original function –> homologous genes that are the result of a speciation event
paralogs
genes related by duplication within a genome and evolved new functions (homologous genes that are the result of a duplication event
what have more meaning
phylogenic relationships
phylogeny
study of the evolutionary history of organisms- both living and extinct e.g. it appears that A is more closely related to B than H, but actually H is ore closely related due to them coming from the same stem

what does the tree of life show
all if has one origin

three basic groups in tree of life
eukarya, prokaryote and archea
Monophyly
monophyletic group is a taxon (group of organisms) which forms a clade, meaning that it consists of an ancestral species and all its descendants
diagram of monophyly
Monophylyl also shows all descendents

morphological issues
parallel evolution, convergent evolution and secondary loss

parallel evolution
independent evolution of same feature from same ancestral condition
example of parallel evolution
european and south american sabre toth
convergent evolution
independent evolution of same feature fromm diff ancestral condition
secondary loss
reversion to ancestral condition
large subunit of ribosome
49 proteins and 3 RNA
small submit of ribosome
33 proteins and 1 RNA molecule
ribosome in total has
82 proteins and 4 RNA molecules
advantage of molecular data
many genes are present in all organism and data set is as large as genome size
rRNA universally presents genes (3)
1) all organisms known are DNA based 2)all use ran intermediates during transcription/translation 3) ribosomal RNAs (rRNA) universal genes
why can alignment be used
due to secondary structures- homologous residues can be identified. Used to produce most likely phylogenetic tree
