1. Darwinian Descent with Modification

2. Evolution Evolution: Natural selection: Evolutionary adaptations:
the change over time of the genetic composition of populations
Natural selection:
populations of organisms can change over the generations if individuals having certain heritable traits leave more offspring than others (differential reproductive success)
Evolutionary adaptations:
a prevalence of inherited characteristics that enhance organisms’ survival and reproduction

3. Evolutionary history Linnaeus: taxonomy Lyell: uniformitarianism
Hutton: gradualism
Lamarck: evolution
Malthus: populations
Cuvier: paleontology
Lyell: uniformitarianism
Darwin: evolution
Mendel: inheritance
Wallace: evolution

4. Fossils and Acquired Traits
Georges Cuvier ( )
Palentologist
Older fossils found in deeper layers of rock
Catastrophism- each strata of rock represents a “catastrophe” in history
Jean-Baptiste de Lamarck ( )
First theory of evolution using fossil record
Organisms pass on “acquired traits”

5. Darwin’s Voyage
Darwin took a 5-year voyage on the HMS Beagle ( )
Studied species and fossils in South America
Fascinated by unique species on the Galapagos Islands

6. Variation Among Species

7. The Origin of Species
Darwin wrote an essay on his observations in 1844
He feared controversy, so he didn’t publish it
Similar theory written by Alfred Russel Wallace in 1858
Darwin compiled his observations and published The Origin of Species in 1859
2 Major Theories:
Descent with Modification
Natural Selection/Adaptation
November 24, 1859

8. Descent with Modification
Modern organisms have evolved from common ancestors
99% of all species that ever lived are now extinct

9. Natural Selection 3 Inferences: 5 observations: Struggle for existence
Non-random survival
Natural selection (differential success in reproduction)
5 observations:
Exponential fertility
Stable population size
Limited resources
Individuals vary
Heritable variation

10. Artificial Selection Selective breeding of plants and animals
Can create drastic changes over only a few generations

11. Natural Selection Overview
Species vary; the more fit ones survive to reproduce
Over time, organisms increase their adaptation to their environment
If conditions change, species will often change to be better suited

12. Examples of Natural Selection
Guppy size determined by predators present
Evolution of HIV
Drug resistance (those that are resistant survive and continue to reproduce)

13. Evolution evidence: Comparative Anatomy
Homologous structures (homology)
Descent from a common ancestor
Vestigial organs
Whale pelvis
Snake hindlimbs
Wings on flightless birds

14. Evolution evidence: Comparative Embryology
All Vertebrates show similarities in embryology
Pharyngeal pouches (gills)
Post-anal tail

15. Evolution evidence: Molecular Biology
Similarities in DNA, proteins, genes, and gene products
Common genetic code

16. Evolution evidence: Biogeography
Geographical distribution of species
Examples:
Islands vs. Mainland
Australia
Similar species on different Continents

17. Evolution evidence: The Fossil Record
Succession of forms over time
Transitional links
Vertebrate descent