1. EVOLUTION
The evidence
© 2016 Paul Billiet ODWS

2. Systematics
Collections of animals and plants in museums from 17th century
Need for systematic classification
Carl Linneus (1735) The binomial classification
To “put order into God’s creation”
Jardins des Plantes Paris
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3. Binomial system Homo sapiens Genus Species Capital case Small case
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4. Levels of hierarchy Taxon Domain Kingdom Phylum Class
Based on relatedness (phylogeny) but artificial
Order
Family
Genus
Species
Some biological basis
© 2016 Paul Billiet ODWS

5. Comparative Anatomy
Classification  comparisons of shape and form  comparative anatomy
Comparative anatomists noticed that different species have the same structures used for different functions (e.g. the pentadactyl limb of terrestrial vertebrates)
These are called homologous structures.
© 2016 Paul Billiet ODWS

6. The pendadactyl limb
Lizard
Frog
Bat
Human
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7. Comparative Embryology
Vertebrate embryos Ernst Haeckel 1892
Early embryos of animals show similar features
Revealing a common ancestry
Their similarity diverges as they develop (Von Baer)
More distantly related species diverge earlier
© 2016 Paul Billiet ODWS

8. Comparative biochemistry
Protein molecules the bottom line in studying the phenotypes of organisms
Similarities and differences in the amino acid sequences of the same molecule (e.g. haemoglobin) taken from different species produce a phylogeny
The phylogeny revealed by studying protein structure ≈ phylogeny of comparative anatomy and embryology but with a much finer resolution.
© 2016 Paul Billiet ODWS

9. Molecular genetics
Comparison of the base sequences of variable regions of DNA taken from different organisms
In particular mitochondrial DNA
The genotype is being analysed
Rates of mutations are assumed to be constant
The analysis of DNA provides a molecular clock against which the geological clock can be compared.
© 2016 Paul Billiet ODWS

10. Phylogenetics
Classification led to phylogeny: the study of related groups as revealed by systematic classification
Closely related organisms are more similar than distantly related organisms
Currently the systematic analysis of relatedness uses a technique called cladistics.
© 2016 Paul Billiet ODWS

11. Cladogram for the birds
Modern birds
no teeth, horny beak
Archeopteryx
reversed first toe, fewer than 26 tail vertebrae
Velociraptor
halfmoon-shaped wrist bone
Allosaurus
three fingered hand
Coelophysis
three functional toes and hollow bones
Titanosurus
Other dinosaurs
Node
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12. PALAEONTOLOGY
The study of fossils
© 2016 Paul Billiet ODWS

13. The formation of fossils
Fossils are generally of rock that has replaced the preserved organism or its traces
Usually occurs when the organism is covered quickly so it is preserved
Sediment, forming sedimentary rock, is then laid down
Petrifaction follows.
© 2016 Paul Billiet ODWS

14. The formation of fossils
Not all fossils are petrified
Some are preserved by: dehydration (mummified), in ice, in peat bogs, in tar beds trapped in amber.
© 2016 Paul Billiet ODWS

15. Fossil DNA
The current limit for fossil DNA appears to be about years old
Oxygen and water damage the molecule with time.
© 2016 Paul Billiet ODWS

16. Finding fossils
Fossils are only formed under certain conditions and then have to be uncovered
Natural erosion exposes the deeper, older layers containing the fossils
Gorges, quarries, caves and desert areas
Fossilisation is rare Fossil discovery is even rarer
The fossil record is very incomplete
Gaps in the record Restricted distribution of many species
Palaeontologists can improve their chances by searching systematically in places where fossils are likely to be found.
© 2016 Paul Billiet ODWS

17. Common ancestors & missing links
Evolution from a common ancestor, would explain their common features
Fossils found close to the origin of a common ancestor
These are called missing links (e.g. Archaeopteryx a fossil dinosaur with bird-like features)
Archaeopteryx
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18. Artificial selection Evolution on a very short time scale.
Wild boar
Domestic pig
9000 years
Evolution on a very short time scale.
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19. The Neolithic Revolution
Sami herding reindeer
The origins of domestication began about years ago
Animals that naturally form herds were probably followed by nomads and gradually domesticated
Selective breeding followed.
© 2016 Paul Billiet ODWS

20. Selecting characters Higher production (more offspring, faster growth)
Higher quality produce
Material of a specific quality (white fleece)
Less aggressive behaviour
Climatic tolerance
Eventually, disease resistance.
© 2016 Paul Billiet ODWS