Lab 1: Systematics

Systematics

the science that studies the evolutionary relationship among species (or groups of species)

Taxonomy

the part of systematics that deals with the practice of describing, identifying, and classifying species

“a kind of sort”

the meaning of the Latin *speci* that species comes from

forensics; public health and medicine; wildlife management; baseline for comparative research; understanding the evolution of specific characteristics; phylogeography

uses of systematics

Biological Species Concept (BSC)

“species are groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other groups” – considered populations of the same species if they can reproduce and produce fertile and viable offspring

asexually reproducing organisms; fossils; hybrids (common in plants)

exceptions to the Biological Species Concept

phylogenetic tree

diagram that depicts the lines of evolutionary descent of different species, organisms, or genes from a common ancestor

Linnaeus

Swedish scientist (1700s) who invented system of classification in biology

Binomial nomenclature and hierarchical classification

the two classifications of species

Binomial classification

2 names: Genus epithet

ex: Homo sapiens

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

Hierarchial classification

Phyla

plural of Phylum

Genera

plural of Genus

characters

characteristics or traits

anatomy/anatomical features; nucleic acid sequences; behavior (song patterns, etc)

kinds of characters that can be used to identify species

Homology

similarity based on common ancestry

developmental homolgy

similairites between species in embryonic stage

molecular homology

genes inherited from common ancestor, similar sequences in same order on chromosomes

Analogy

the result of convergence; similarity not based in common ancestry

Homoplasy

an analogous trait

independent acquisition; reversal

kinds of homoplasy

analogous; homologous

bat wings and bird wings are _______ traits while bat arm/finger bones and bird arm/finger bones are ________ traits

analogous; independent acquisition/convergent evolution

the common dolphin and ichthyosaur have _______ traits that are from __________/_________

phylogenetic trees (cladograms)

Hypotheses of evolutionary relationships

node

speciation event

unresolved node

uncertain relationship

internode

common ancestor

sister group

closest relative

phylogeny

classifications should be based in __________

monophyletic

group/taxa that includes all the descendants and their most recent common ancestor

paraphyletic

group/taxa that includes most recent common ancestor but not all descendants

polyphyletic group/taxa

group/taxa that does not include common ancestor

synapomorphy

shared derived (evolved later from other trait) character

plesiomorphy

shared ancestral trait