Topic 2 Flashcards
What is Scala Nature? Who created it?
A scale made by Aristotle that showed the rankings of organisms. It was not phylogenetic.
What is nomenclature?
A system of rules for naming things
What is taxonomy?
The practice of naming and classifying organisms
What are systematics?
The theory and practice of classifying organisms based on evolutionary history
What was the Linnenan System?
A system that classified organisms into Kingdoms, Phylum, Class, Order, Family and Genus. This was based on similarities
What are phylogenetic trees?
Hypotheses for evolutionary relationships
What is a taxon?
A named group at any level of classification
What is a clade?
A valid group includes the ancestor at any node and all of its descendants
What are sister taxa?
Taxa that share a common ancestor
Can phylogenetic trees rotate?
Yes they can like a mobile. Its important to look at the relationships, not the structure of the tree
What is an In-Group?
Groups whose relationships interested in untangling
What is an Out-Group?
One or more taxa that are distantly related to the ingroup but have diverged from it at an earlier time
What is a character?
Type of structure, behavior, DNA sequence, etc.
What is a state?
The expression of a character
What is the principle of parsimony?
Choose the phylogeny with the fewest number of evolutionary events, because it is more probable
What is an event?
Change from ancestral state
What is a synapomorphy?
A shared, derived state
What is a derived state?
The current organisms has this trait but its ancestors do not
What is an ancestral state?
The current organism and its ancestors had this trait
What is symplesiomorphy?
A shared, ancestral state. These are not useful for phylogenetic trees
What is a homologous trait?
A trait that looks the same and has the same evolutionary origin
What is an analogous trait?
A trait that looks the same but actually evolved independently
What is convergent evolution?
When organisms independently evolve similar traits
What are molecular phylogenetics?
Matching of bases in gene sequences between species. The more matches means the closer related species are.
what does monophyletic mean?
Contains a common ancestor and all of its descendant and no other unrelated taxa
What does paraphyletic mean?
Groups that do not contain all of the descendants of a common ancestor. Usually caused when taxa who are very dissimilar to the rest are removed
What does polyphyletic mean?
Taxa get lumped together even though they do not share recent common ancestors
