evolution- the tree of life Flashcards
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
if duplications occur
new functionality can occur. if such duplications occurred a long time ago they might be universal among the three domains of life
rooted universal tree
currently there are a few known gene duplications. All show the same topology for the universal tree –>Eukaryotes and archaebacterial are sister groups
Darwin on how life first evolved
in some warm litter pond with all sorts of ammonia and phosphoric salt, life, heat and electricity and present, that a protein compound was chemically formed, ready to undergo more complex changed
black smoker
no little ponds as no continents. Over 350 degree. ATP instantly degrades at 150 degree
white smoker
Much colder than black smoker- 40-90 degrees.
Methane and hydrogen rich, alkaline, trace metals.
-Biogenic hydrocarbon production
ancient
-up to 60m tall. -can live over 10,000 years -fossilsed version found -360mya -hollow and full of tiny chambers within walls of pyrite –> early reaction vessels>
chemical evolution driven by
pH tem and redox gradient
prokaryote diversity
individual lineage of archaebacteria and eubacteria- could have evolved. Many basic aspects of life are identical but also many defining features are different
most notable diff in archaebacteria and eubacteria
the membrane
need to be homologous characters when comparing because
comparing non -homologs results in incorrect relationship assumption
tree of life is based on
ribosomal RNA
why is it important to identify the root of life
allows you to identify who is closer related to who
third domain of life
carl worse identified a third domain: archaebacteria in 1977
archaebacteria
the third domain- mainly extremophiles- can grow in extreme temps
diagram of prokaryotic diversity
….
paralogue
either of a pair of genes that derives from the same ancestral gene. (genomics) a pair of genes that derives from the same ancestral gene and now reside at different locations within the same genome.
