Ch 23: Understanding Diversity: Systematics

phylogeny

systematics

taxonomy

taxon

How to categorize life?

life vs. non-life (?prehistory)

plants (non-motile) vs. animals (motile) Greek philosophers including Aristotle (born 384 - died 322 BC)

add Protista/Protoctista & sub-group Monera (Haeckel 1866)

prokaryotic vs. eukaryotic cells (Chatton 1937)

reorganized classification into 4 kingdoms (Copeland 1930s?)

5 kingdoms; adding Fungi (Whittaker 1959)

3 domains (Carl Woese 1977)

Carol J. Bult

further elaborated by Mitchell Sogin (early eukaryotes) & many others

-> 6 kingdoms (compromise)

still argued: Lake’s 4 domains, Cavalier-Smith & others’ > 6 kingdoms

horizontal gene transfers

genome fusions

clades?

Groups of organisms on a phylogenetic tree (excluded)

Homologous structures

18-13 terrestrial vertebrate forelimbs

18-14 modified leaves

Australian marsupial “mole”

N American placental mole

Homoplasies = analogous structures

18-16 spiky plant parts

Phenetics/evolutionary systematics

numerical taxonomy

eg: Birds -> different enough to be a separate class from reptiles

Cladistic systematics

clade

cladogram

synapomorphy vs. (sym)plesiomorphy

outgroup

parsimony

eg: Birds -> sub-group of Reptile class

Morphology

Morphology: Developmental data

eg: early animal embryo cleavage (30-5)

Biochemistry: Lipids

2 species of Pseudomonas

Biochemistry: Proteins

eg: Isozyme patterns from a fungus

Biochemistry: Proteins

eg: amino acid sequence comparison

myoglobin

Biochemistry: Proteins

eg: 3D structure comparison

Relationships between canids using DNA sequences

Biochemistry: DNA

Sequence analysis

Stoneking, et al.

Mitochondrial DNA study of humans

2 representations of the same data

Phylogram - shows genetic change

Ultrametric tree - shows time

Other kinds of trees

Methods of generating trees

Distance

Parsimony

Maximum likelihood