Chapter 10 Taxonomy & Phylogeny

Taxonomy

the naming/classification of a species, and a part of systematics (comparative biology)

Binomial Nomenclature

Using Latin to name an animal with ‘Genus species’ (Gorilla gorilla, Homo sapiens)

Taxonomic hierarchy (least specific to most specific)

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Taxon

group of species, or of populations of organisms, or organisms considered to form a UNIT (depends at what level we position the grouping)

Biological Species Concept: (what makes a species?)

organism that has a similar common descent, smallest distinct groupings based on homologies (morphological characteristics, molecular, biochemical, chromosomal), and reproductive community/ability to breed with each other

Speciation

Formation of new species, a population can no longer interbreed/reproductively isolated

Allopatric speciation

due to geographic separation (isolation is isolated physically, and divergence begins)

Sympatric speciation

due to differential specialization (individuals become specialized for occupying different components of the environment)

Phylogenetic trees

hypotheses of evolutionary relationships between different groups of organisms based on finding characters that species have in common from a common ancestor (consequence of systematization)

homologous character

similar structures because they were inherited from a common ancestor that also had that character, but different function (Positive anatomical parts)

Analogous character

structures in different organisms that appear similar in function and appearance but evolved independently from each others (convergent evolution)

synapomorphy

shared, derived character, common between an ancestor and its descendants, define monophyletic groups

monophyletic group

includes organisms with a common ancestor and all descendants

paraphyletic group

includes organisms with a common ancestor, but not all descendants

node

speciation event on the phylogenetic tree

root

the first common ancestor on the phylogenetic tree

branch

lineages on the phylogenetic tree, shared or unique

clade

basic unit of phylogenetic tree, monophyletic

cladogram

branching diagram showing a clade within a clade (not the same as phylogenetic tree)

sister groups

share a MRCA and are the CLOSEST relatives in a group

parsimony

out of all possible explanations for a phenomenon, the simplest of the set is most likely to be correct (the simple way is the best way)