Ch 23: Understanding Diversity: Systematics
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Transcript of Ch 23: Understanding Diversity: Systematics
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