Flashcards in Oct 14 Deck (33):
Who posited that life could be hierarchically organized or classified according to similarities?
Darwin showed that descent with modification could explain and support Linneaus’ hierarchical organization through similar features
The evolutionary process of branching descent with modification generates nested hierarchies of similarities
What are the components of modern phylogenetics?
classification using similarities + branching descent
What is the study of patterns of branching relationships of populations that give rise to populations over evolutionary time
What is the aim of phylogenetics?
a) discover shared ancestry btw organisms
b) identify history of descent between
populations characterized by shared features
c) all of the above
c) all of the above
What is used to construct phylogenies?
Traits are used to infer...
patterns of ancestry
sequence and timing of events
Darwin inferred common ancestry and demonstrated its underlying mechanisms
Darwin predicted the presence of heritable material but it was not proven until DNA was discovered
DNA sequence similarity should reflect patterns of common ancestry inferred from morphological traits and fossil evidence if...
descent with modification holds
What is a taxa?
related organisms (species, genera, phyla)
What does an interior node in a phylogenetic tree represent?
hypothetical common ancestor for connected taxa
What does a root in a phylogenetic tree represent?
convergence of all taxon relationships
What is polytomy and what does it represent?
>2 taxa emerge from a node
uncertainty about evolutionary relationships
What are sister taxa?
taxa derived from the same recent ancestor
What is an outgroup?
an early branching relative of the interest groups
___ is group of organisms with a
What is a monophyletic group?
includes the most recent common ancestor of a group of organisms, and all of its descendents
What is polyphyletic group?
does not include the recent common ancestor
What is a paraphyletic group?
includes the most recent common ancestor, but not all of its descendents
What is the difference btw a rooted tree and an unrooted tree?
Rooted trees indicate a common line of descent through time
Unrooted trees do not strictly illustrate evolutionary relationships
What is a phylogram?
evol. relationships and changes over time (branch lengths)
-longer branches = more changes
What is a chronogram?
relationships, changes calibrated to actual time
What type of tree shows only evolutionary relationship?
(Short-lived/long-lived) organisms have more heritable changes?
Short-lived bc faster mutation rates
Which evolved more slowly, shrubs/trees or herbaceous plants? Why?
shrubs/trees bc fewer generations per year
What is the difference btw a homologous and analogous trait?
Homologous traits due to ancestral inheritance
Analogous traits are similar but not of ancestral origin
What is a homoplasy?
What is divergent evolution? Give example
closely related organisms diverge ie. different colored mice
What is convergent evolution? Give example
similar traits arise in non-related organisms ie. light lizards and mice in desert
What is a synapomorphy?
derived trait that is shared by two or more taxa and inferred to have been present in their most recent common ancestor, whose own ancestor in turn is inferred to not possess the trait
What is symplesiomorphy?
ancestral state is not shared by closely related
What slow-evolving traits are good for drawing trees?