Ch 26: Phylogeny and the Tree of Life Flashcards
What is phylogeny?
the evolutionary history of a species or group of related species
What do systematics classify?
they classify organisms and determines their evolutionary relationships
What is taxonomy?
ordered divisions and classifications of organisms
What is a taxon?
a taxonomic unit at any level of the hierarchy
What do phylogenies show?
phylogenetic trees do show patterns of descent, determining taxonomic identity or population, and showing relatedness between species of interest
What is homology?
is similarity due to shared ancestry
What is analogy?
is similarity due to convergent evolution
What are cladistics?
groups of organisms by common descent
What does monophyletic group contain?
group contains all descendants of a common ancestor
What does paraphyletic group contain?
group does not contains all descendants of a common ancestor
What does polyphyletic group contain?
group contains two or more descendants of a common ancestor
What is a molecular clock?
uses constant rates of evolution in some genes to estimate the absolute time of evolutionary change
What is an orthologous gene?
homologous genes found in different species following speciation
What is an paralogous gene?
genes resulting from duplication events within a single species
What are some issues to consider when using a molecular clocks?
genes that are not under strong selection are more likely to change at a constant rate than genes under selection, use of multiple genes is more reliable than using a single gene, and estimates of evolutionary divergences older than the fossil record have a high degree of uncertainty because there is no way to “calibrate” the molecular clock
