1. Evolution
Descent with Modification: A Darwinian View of Life

2. Evolution Defined
Evolution: gradual hereditary changes in groups of living organisms over time.
November 24, 1859

3. Lamarck’s Theory Jean Baptiste de Lamarck, 1809
First theory of evolution- how species change

4. Lamarck’s Theory
**Inheritance of acquired characteristics- The changes acquired during an animals lifetime from use and disuse may be passed on to its offspring.
Law of use and disuse- parts used by animal become stronger, parts used less become weaker

5. Darwin vs. Lamarck

6. Charles Darwin Father of Evolution
Developed the theory of evolution after his trip on the H.M.S Beagle
Published the Origin of Species on November 24,1859

7. Darwin’s Voyage

8. Galapagos Islands
Noted subtle differences in finches & tortoises, by island & compared to mainland

10. Actual photos of the finches

11. Niches of Darwin’s Finches

12. Darwin’s Theory
Variation- There is a natural variation in any population.
Overproduction- more offspring are born than survive.
Competition- members of a species compete for food, habitat, etc. (limits population)
Adaptations- any inherited trait that improves survival.
Natural selection- “survival of the fittest”- The species most fit for their environment will survive to pass on their traits.
Speciation- If enough changes take place, new species may be formed

13. Keep in mind……
Populations or species evolve, not individuals

14. Major pieces of Evidence for Evolution
Fossils
Comparative Anatomy (homologous structures, vestigial structures, analogous structures)
Comparative Embryology
Biochemical Evidence
Biogeography
Selective Breeding of Animals and Plants
Post Darwin:
7. Molecular Genetics: DNA/Amino acid Sequencing
8. Chromosomal Changes (Mutations)

15. 1. Fossil Evidence
Fossils: remains and traces left behind by organisms -most direct evidence for evolution -provides a record of ancient organisms that have existed -able to generate a timeline -observe the presence of vestigial structures -ancestral descent and lineages can be generated -more aquatic fossils vs. terrestrial have been found Types of Fossils: imprints, hair, nails, tissue, and other remains Locations: sedimentary rock, ice, amber, tar, quicksand, petrification

16. Evidence: 1. The Fossil Record
Shows succession of forms over time
Transitional links
Vertebrate descent

17. Ex- Evolution of the Horse
Horse Evolution: The fossil record shows:
Size:
Smaller to larger
Toes:
3 toes on back foot/4 on front
1 toe bigger/2 toes reduced = HOOF!
Molars:
Eating leaves to grazing = bigger teeth

18. Dating Fossils Location within the rock strata (use index fossil)
Radioactive isotopes (half-life)
K40 half life is billion years argon
U235 half life is 704 million years → lead
U238 half life is 4.5 billion → lead
C14 half life is years  nitrogen

19. Evolution Evidence: 2. Comparative Anatomy
Homologous Structures
3 Types of Structures:
A. Homologous structures (same structure, diff. use)
Shows possible descent from a common ancestor
B. Vestigial structures (no apparent use today)
Ex: whale/snake hindlimbs; wings on flightless birds

20. Extinct Whale w/ small hind limbs- Vestigial Structure

21. Analogous Structures C. Analogous Structures-
Same function, but different structure.
-see examples here.
Show Convergent Evolution due to similar niches.

22. Evolution Evidence: . 3. Comparative Embryology
Vertebrate embryos- look very similar during early development.
Pharyngeal pouches (gills), ‘tails’ as embryos
Indicates common ancestors.

23. Evolution Evidence: 4. Comparative Biochemistry
Biochemistry is used to support evidence about evolutionary relationships
Similar molecules in different species determine how much difference there is between the species.
More differences = longer time span since common ancestor
Less differences = shorter time span since common ancestor

24. Evidence: Molecular Biology
Mutations in a genome occur at a predictable rate. Therefore, base pair sequences in two populations can be compared, in particular amino acid sequences, and by looking at the number of mutagenic differences between the two, and inference can be made as to how long ago the two populations diverged reproductively.
ATTGCCAAGCCT
ATTGCGAAGCCT

25. Evolution evidence: 5. Biogeography
Geographical distribution of species
Examples:
Islands vs. Mainland
Australia
Continents

26. Specific molecules can indicate phylogeny!
Phylogeny: is the line of evolutionary descent

27. Common Ancestory- Phylogenic Tree

28. Phylogenic Tree with humans

29. Molecular evidence for common Ancestry

30. 6. Selective Breeding
For millenia, we have bred various animals and plants for specific purposes, selecting the traits WE want them to acquire.
Ex- horses, dogs, strawberries, corn
This is controlled evolution.

31. 7. Examples of Natural Selection
Peppered moth
antibiotic resistance

32. Examples of Modern (Recent) Evolution
Peppered Moth- during day sits on tree trunk. More active at night.
Before 1850 tree trunks were light in color, and most moths were gray.
After 1850 (industrial revolution), the predominant color of moth was black, which matched the soot on the trees.
peppered moth activity

33. Percentage of Antibiotic Resistant Gonorrhea Strains 1980-1990

34. Key Points to Remember A population evolves not an individual organism
The accumulation of small changes over long periods of time results in larger changes
A new species emerges with slightly different characteristics usually because of being isolated.
How and why organisms are able to transmit heritable traits to the next generation was not explained by Darwin.
Common Ancestry!

35. Evidence for evolution!!
includes
Evidence of Evolution
Physical remains of organisms
Common ancestral species
Similar genes
which is composed of
which indicates
which implies
The fossil record
Geographic distribution of living species
Homologous body structures
Similarities in early development

36. Final words…...
“Absence of evidence is not evidence of absence.”