CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS
Brief Introduction to
the Theory of Evolution
Anders Gorm Pedersen
Molecular Evolution Group
Center for Biological Sequence Analysis
gorm@cbs.dtu.dk
CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS
Classification: Linnaeus
Carl Linnaeus
1707-1778
CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS
Classification: Linnaeus
• Hierarchical system
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Kingdom
Phylum
Class
Order
Family
Genus
Species
(Rige)
(Række)
(Klasse)
(Orden)
(Familie)
(Slægt)
(Art)
CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS
Classification depicted as a tree
CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS
Classification depicted as a tree
Species Genus Family
Order
Class
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Theory of evolution
Charles Darwin
1809-1882
CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS
Phylogenetic basis of systematics
•
Linnaeus:
Ordering principle is God.
•
Darwin:
Ordering principle is shared descent
from common ancestors.
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Today, systematics is explicitly based
on phylogeny.
CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS
Darwin’s four postulates
I.
II.
III.
IV.


More young are produced each generation than can survive to
reproduce.
Individuals in a population vary in their characteristics.
Some differences among individuals are based on genetic
differences.
Individuals with favorable characteristics have higher rates of
survival and reproduction.
Evolution by means of natural selection
Presence of ”design-like” features in organisms:
quite often features are there “for a reason”
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Theory of evolution as the basis of
biological understanding
”Nothing in biology makes sense, except in the light of
evolution.
Without that light it becomes a pile of sundry facts some of them interesting or curious but making no
meaningful picture as a whole”
T.
Dobzhansky