BIO 181 Unit 3

Domains of Life

Archaea + Bacteria → Eukarya

John Ray

defined what a species is

Carolus Linnaeus

father of taxonomy - created binomial nomenclature

Taxonomic Categories

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

Domain

Eukarya

Kingdom

Animalia

Phylum

Chordata

Class

Mammalia

Order

Primates

Family

Hominidae

Monophyletic

common ancestor and all its descendants

Phylogeny

evolutionary history and relationship of organism/group

Synapomorphies

organism group based on shared derived characteristics

Cladistics

reconstruct phylogenetic trees by considering evolutionary pathways

Clade

evolutionary ancestors and common ancestor descendants

Sister Clades

share immediate DNA; closest relatives

Cladogram

diagram showing evolutionary relationships

Phylogenetic Trees

cladogram that shows evolutionary times and based on homology

Homology

traits inherited from a common ancestor

Ancestral Trait

symplesiomorphy- in ancestor of group, could be retained or changed in descendants

Derived Trait

synapomorphy- differs from ancestral form; evolutionary novelty

Cladistics

reconstructs phylogenetic trees by considering various evolutionary pathways

Analogous Characters

similar due to functional or ecological constraints/pressures; similar in appearance due to evolutionary convergence

Homologous Characters

similar due to evolutionary convergence

Homoplasies

features shared between species not inherited from a common ancestor

Principle of Parsimony

preferred explanation is the simplest explanation

Monophyletic Trees

common ancestor and all descendants included

Polyphyletic Trees

more than one phylogeny; common ancestor not included

Paraphyletic Trees

common ancestor and some of the descendants

Homologous

similar trait in different species from a common ancestor

Homoplastic

similar trait without common ancestor

Heterologous 

evolutionarily unrelated traits

Diphyletic

common ancestor and som descendants

3 Domain System

bacteria, archae, eukarya

Characteristics to Classify Organisms

life cycles, extraembryotic membranes, excretory product, temperature regulation, skull types

Haploid

one set of chromosomes (n)

Diploid

2 sets of chromosomes (2n)

Gametes

sex cells (haploid)

Gametophyte

gamete-producing structure

Meiosis

cell division process; yields haploid gametes/spores

Mitosis

cell division process; yields identical cells

Sporophyte

diploid multicellular organism

Non-Amniotes

eggs laid in water; no special water-filled enclosure

Amniote

group of tetrapods that have an egg w amnois + protected by amniotic membranes; mammals

Endotherms

produce their own heat

Ectotherms

rely on heat from the environment

Homeotherms

keep body temperature constant

Heterotherms

allow body temperature to fluctuate

Anapsid

skull has no holes or openings

Synapsid

has a hole low in skull

Amnion

protects embryo in sac filled with amniotic fluid

Yolk Sac

contains yolk (mix of proteins and lipoproteins)—sole source of food until hatching