Lecture 1 classification Flashcards
what three things does classification need to be
based on degree of similarity between organisms
precise, fixed, universal application
reflect evolutionary histories
taxonomy
the science of naming and classifying organisms within groups (Taxa)
phylogeny
the evolutionary history of a species or a group of a species (‘tree of life’)
systematics
the science of determining evolutionary relationships among organisms
what is the linnaean system
inclusive hierarchical system of classification
what are the different taxa in the linnaean system
kingdom phylum class order family genus species
what is binomial nomenclature?
organisms have two part scientific names (in Latin): Genus & Species
how to write scientific names
Taxa above species always start with a capital letter (e.g. Hominidae, Homo etc.)
Only names of genus & species in italics, but always in italics (or underlined)
how to write common names
English (common names) usually start with a lower case letter (e.g. red squirrel – but Egyptian vulture)
Name of the person who first described a species often follows the species’ name (with the year)
what criteria are used to classify organisms
morphological characters
fossil record
embryology
molecular analysis(genetic differences)
what are morphological characters
Shape/size/colour/etc are morphological characters of an organism or its specific parts. Morphology describes structural features.
homologous characters
features that are realated due to common ancestry
analogous (homoplastic)
features that are similar due to common function but have evolved separately
example of homologous characters
bone structure in mammals
example of analogous characters
swordfish fish
dolphin mammal
ichthyosaur reptile
analogous characters are the result of ———evolution
convergent
what are the two types of homologous characters
primitive
derived
what is a shared primitive character
a character that is shared beyond the group we are trying to define
what is a shared derived character
an evolutionary novel character unique to the group we are trying to define
how is milk derived and primitive
derived when compared to other vertebrate
primitive compared to other mammals
what can be used to help find primitive characters
fossil records
if the fossil record is poor what can also be used
embryology and vestigial organs
example of embryology
fish reptile bird and human all have gill slits and tail on embryo = common ancestor
what is molecular analysis used for
to measure genetic similarity
