bio exam 1 Flashcards
Dichotomous keys
an organized set pf couplets (two statements) that consist of mutually exclusive characteristics
2 types of dichotomous keys
bracketed and indented
reading a phylogenetic tree
Root: the common ancestor of all taxa
Node: represents a taxonomic unit or a branching point
Branch: defines the relationship between the taxa and changes in traits over time
Outgroup: a taxon that shares ancestral traits with the rest of the group, but is distinct
Polygamy: a node with more than two branches, often occurs when differences are not known
monophyletic group (clade)
group of organisms descended from a common ancestor
polyphyletic group
group of organisms descended from different common ancestors
paraphyletic group
group of organisms descended from a common ancestor but does not include all descendants or the common ancestor
homologous/synapomorphies
traits that are shared between organisms and are derived from a common ancestor
symplesiomorphies
traits that are shared between all organisms in a given phylogenetic tree
traits shared by all organisms
RNA, DNA, proteins, cell membranes
evolution
a change in the genetic composition of a population over time
population
a group of organisms of the same species that (1) occur in the same area and (2) interbreed or share a common gene pool
gene pool
genes available in a population
genes
sequences of DNA or RNA that code for a molecule
alleles
genes that are responsible for variability
dominant (P) recessive (p)
genotype
a genetic constitution for a specific organism