chapter 20: the history of life Flashcards
How do biologists group organisms
they based them on shared/like characteristics
what are the characteristics that biologists group organisms by
- fossil records
- morphology
- physiology
- behaviour
- embryological development
- DNA or RNA sequences
what is systematics
reconstruction and study of evolutionary relationships
what is an important thing to note about tree of life diagrams
they are subjective as they are based on the authors beliefs
what is phylogeny
the hypothesis about relationships among taxonomic groups (is displayed through phylogenetic trees or cladograms)
what are the types of phylogenetic trees
- rooted
- unrooted
what is a rooted phylogenetic tree
uses single linage and represents a common ancestor at the base
what is a unrooted phylogenetic tree
a diagram that is used to show the relationship between species but does not display a common ancestor
what is the assumption that can be made when examining a rooted phylogenetic tree
in the common ancestor is not stated at the base then it is assumed to be Luka
what are the are the parts of a phylogenetic tree
- taxon
- clade
- branch point (node)
in regards to phylogenetic tree what is a taxon
the group of organisms
in regards to phylogentic tree what is a claude
any branch or lineage that links taxons and branch points to the common ancestor
in regards to phylogenetic trees what is a branch point / node
any point where a single lineage splits into two seperate clades (any branch point / node is where the most recent common ancestor (MRCA) is found)
what are sister taxas
when two species are linked to the same closet branch points / nodes
what is taxnomy
a science of classifying organisms into taxas