Chapter 26: Phylogeny and the Tree of Life Flashcards
What is phylogeny?
the evolutionary history of a species or group of species
What is Linnaean Classification of Organisms?
hierarchy based only on morphological similarities
What are morphological similarities?
physical similarities
What are the taxa of Linnaean’s hierarchy from smallest (most similar) to largest (least similar)?
species, genus, family, order, class, phylum, kingdom, domain
What does taxa mean?
group of organisms (ex- species, genus, family)
What is the first part of an organism’s scientific name?
the genus to which the species belongs
What is the second part of an organism’s scientific name?
the specific epithet unique to each species
What is the major problem with Linnaean classification?
It doesn’t specify relationships between these organisms, it just acknowledges their degree of similarity
What is the branch point of a phylogenetic tree?
point where lineage diverges, representing a common ancestor
What are sister taxa?
most closely related taxa on phylogenetic tree
What is a polytomy on a phylogenetic tree?
point where pattern of divergence is unknown to scientists; distinguished by a branch point that has more than 2 lines
What is a basal taxon in a phylogenetic tree?
lineage that diverges early in the tree so it originates near the common ancestor of the tree
What do “deeper” branch points represent on a phylogenetic tree?
progressively greater amounts of divergence
What 2 characteristics do scientists use to build phylogenetic trees and which is more accurate?
Morphological similarities, genetic similarities (more accurate)
How do scientists measure morphological similarities?
Fossil records, modern biology of the organisms
What is the problem with using morphological similarities to build phylogenetic trees?
similar morphology can sometimes be misleading because of the difference between homology and anology
How do scientists measure genetic similarities?
They sequence whole genomes and determine similarity between the DNA of two species
What is true homology?
A trait that is shared because it arose from acommon ancestor (ex- legs in tetrapods)
What is anology?
morphological similarities that arose separately & coincidentally in different ancestors (ex- wings on bats and birds)
What is another word for anology?
convergent evolution
What are homoplasies?
analogous structures (ex. wings)
