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Classification and phylogeny
Early classification schemes
Fish & whales
Flies & birds
Frogs & alligators
Squirrels & monkeys
Early classification schemes
Fish & whales
Flies & birds
Frogs & alligators
Squirrels & monkeys
Swim in water
Fly in air
Crawl in mud
Climb in trees
Early classification schemes
Honeybee:
Apis pubescens, thorace subgriseo, abdomine fusco, pedibus posticis glabris utrinque margine ciliatis
Apis mellifera
Early classification schemes
Honeybee:
Apis pubescens, thorace subgriseo, abdomine fusco, pedibus posticis glabris utrinque margine ciliatis
Apis mellifera
Linnaeus introduced: binomial nomenclaturehierarchical classification
Hierarchical classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
How the leopard got its spots
Phylogenetic trees are a visual representation of the fact that species are related by descent from a common ancestor
Phylogeny
Anagensis (phyletic evolution) - successional changes within a single lineage
Cladogenesis (phylogenetic branching) - splits along ancestral line that cause species multiplication (ie. appearance of new clades, clusters of species)
homology - same feature in different species, derived from common ancestor
parallelism - similar feature occurs in different species, but common ancestor was different
convergence - similar feature arose independently in different species
Monophyletic - organisms derive from a single ancestral population
Paraphyletic - does not include all descendents from the ancestral population
Polyphyletic - organisms arrived independently at a particular grade of organization
Phylogeny
Monophyletic Paraphyletic
Paraphyletic groups
Phenetics - applies numerical taxonomy to arranging groups into genera & higher ranks
Cladistics - every significant evolutionary step marks a dichotomous branch
Evolutionary classification - incorporates genealogical relationship between groups with evolutionary distance
Phylogeny
Character a b c d1 1 1 0 02 1 1 0 03 1 1 1 04 1 1 1 05 1 1 1 06 1 1 1 07 0 1 0 08 0 1 0 09 0 1 0 010 1 0 1 011 1 0 0 1
Phenetics
a b c da - 6 7 3b - 4 0c - 5d -
a c b d
sim
ilari
ty
Phenetics
B = (BA + BC)/2B = 5D = 0
Phenograms do not necessarily represent phylogenetic relationships
Similarity - number of character states 2 species share
Relationship - how recently they diverged from a common ancestor
Phenetics
Cladistics
Character a b c d1 1 1 0 02 1 1 0 03 1 1 1 04 1 1 1 05 1 1 1 06 1 1 1 07 0 1 0 08 0 1 0 09 0 1 0 010 1 0 1 011 1 0 0 1
0 pleisomorphic1 apomorphic
Cladistics
a b c da - 6 4 0b - 4 0c - 0d -
a b c d
12
345
6
789
Synapomorphies arise at evolutionary branch points
Taxonomy
Characters must be independent
homologous
Evolutionary relationships only revealed by shared, derived traits
= synapomorphies
Terminology
plesiomorphy
symplesiomorphy
apomorphy
synapomorphy
autapomorphy
Principles of evolutionary change, inferred from systematics
1 homologous features are derived from common ancestors
Principles of evolutionary change, inferred from systematics
1 homologous features are derived from common ancestors
2 homoplasy is common in evolution
Convergent evolution (convergence)
Parallel evolution (parallelism)
Evolutionary reversals
Homoplasy
Principles of evolutionary change, inferred from systematics
1 homologous features are derived from common ancestors
2 homoplasy is common in evolution
3 rates of character evolution differ
Principles of evolutionary change, inferred from systematics
1 homologous features are derived from common ancestors
2 homoplasy is common in evolution
3 rates of character evolution differ
4 evolution is often gradual
Principles of evolutionary change, inferred from systematics
1 homologous features are derived from common ancestors
2 homoplasy is common in evolution
3 rates of character evolution differ
4 evolution is often gradual
5 characteristics often owe their change in form to change in function
Principles of evolutionary change, inferred from systematics
1 homologous features are derived from common ancestors
2 homoplasy is common in evolution
3 rates of character evolution differ
4 evolution is often gradual
5 characteristics often owe their change in form to change in function
6 phylogenetic analysis documents evolutionary trends
Principles of evolutionary change, inferred from systematics
1 homologous features are derived from common ancestors
2 homoplasy is common in evolution
3 rates of character evolution differ
4 evolution is often gradual
5 characteristics often owe their change in form to change in function
6 phylogenetic analysis documents evolutionary trends
7 most clades display evolutionary radiation
Cladistics
Character a b c d1 1 1 0 02 1 1 0 03 1 1 1 04 1 1 1 05 1 1 1 06 1 1 1 07 0 1 0 08 0 1 0 09 0 1 0 010 1 0 1 011 1 0 0 1
0 pleisomorphic1 apomorphic
Cladistics
a b c da - 6 4 0b - 4 0c - 0d -
a b c d111110
10
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