1. Biological Anthropology
Darwin, Mendel, and
The Rise of the Synthetic Theory

2. Three Questions to Answer
Where does variation come from?
How is variation passed on from one generation to the next?
How is the variation present within a species at any time affected by the environment?

3. Science as a revolutionary process
scientific “revolution”
anomalies
“normal” science

4. Normal Science ca. 1600 the origin of living things
Great Chain of Being
Held in the hand of God
Ranked living things as more or less like God
Links represent species
Discrete
Immutable

5. Carl Linneaus by M. Hoffman in 1734.
Carolus Linnaeus
Son of a Lutheran pastor
Groomed to be a pastor
Preferred science
Became a physician and botanist
Carl Linneaus by M. Hoffman in 1734.

6. Binomial nomenclature
Carolus Linnaeus
Systema Naturae (1735, with many subsequent revisions)
Standardized names of plants and animals
Binomial nomenclature
Wedding Portrait of Linnaeus
(1739)

7. Carolus Linnaeus
Before, the common wild briar rose was known variously as
Rosa sylvestris inodora seu canina
Rosa sylvestris alba cum robore, folio glabro
Using binomial nomenclature, names were standardized:
Rosa canina
Coffea arabica
Homo sapiens

8. Carolus Linnaeus 1707-1778 First believed species were immutable
Noticed hybrids
Observed that plant species could change appearance as they acclimatized to new areas
Eventually abandoned idea of fixity of species

9. Georges Cuvier 1769-1832 “Father” of comparative anatomy
Studied the anatomy of vertebrates
Established the field of vertebrate paleontology

10. from Cuvier's 1796 paper on living and fossil elephants
Georges Cuvier
Noted distinct differences between fossil mammoth (top) and living Indian elephant (bottom)
Discovered that species could go extinct
from Cuvier's 1796 paper on living and fossil elephants

11. What had happened to these animals?
Periodic “revolutions” or catastrophes had befallen the earth
These were events that had natural causes
Although Cuvier did not identify these with Biblical events, others would

12. Jean-Baptiste Lamarck 1744-1829
Studied the anatomy of invertebrates
Saw a relationship between an animal’s form and the way it exploited the environment
Argued that a change in the environment could affect the needs of the organisms in that environment, causing them to alter their behavior

14. Lamarck said
Altered behavior led to more or less use of a body part, which would therefore grow larger or smaller
Any such change could be inherited
Trouble is… it’s wrong!

15. James Hutton 1726-1797 Scottish geologist
A cyclical “world machine” that exhibited “no vestige of a beginning – no prospect of an end.”
This view ultimately led to modern geological time scales

16. James Hutton 1726-1797 Pointed out role of erosion Earth was timeless
A self-perpetuating place created for humans
No directional change, only cycles

17. Charles Lyell 1797-1875 Another Scottish geologist
Principles of Geology (3 Volumes; )
Argued that currently active principles were all that was needed to explain the geological history of the Earth

18. uniformitarianism Charles Lyell 1797-1875
Exclude the use of sudden catastrophes when explaining fossils
The earth was extremely old

19. Thomas Malthus
An Essay on the Principles of Population (1798)
Points out that more individuals are born into a species than will ever reach maturity
A struggle for survival

20. Thomas Malthus
"population increases in a geometric ratio, while the means of subsistence increases in an arithmetic ratio."
food supply
population

21. Adam Smith
An Inquiry into the Nature and Causes of the Wealth of Nations (1776)
Laissez-faire economics: markets will perform best if they are allowed to function according to their own principles

22. Adam Smith
Smith’s ideas inspired Darwin in a more general way:
A system, once established, will run itself according to its own principles
A system does not require a higher authority to regulate a system itself

23. Charles Robert Darwin Feb. 12, 1809 – April 19, 1882
father and grandfather were physicians
an avid insect collector from an early age
December begins to study for the clergy at Christ's College, Cambridge
Graduates with Bachelor of Arts degree in April, 1831

24. Charles Darwin
Invited to serve as ship’s naturalist on H.M.S. Beagle

25. The Second Voyage of the Beagle
Departs England on 27 Dec., 1831 – Returns to England on 2 October, 1836

26. The Post-Beagle Period
Darwin settles into a comfortable life
Publishes numerous books
Breeds pigeons

27. The Post-Beagle Period
– serves as Secretary of the Geological Society of London
Becomes friends with Charles Lyell
first mention of the “transmutation” of species in his notes
From Darwin’s notes – ca. 1838

28. Alfred Russel Wallace (1848)
Studies the distribution of animals in the Malay Archipelago
Develops his own ideas about natural selection
Sends Darwin a manuscript in 1858
Alfred Russel Wallace (1848)

29. July 1, 1858
Ideas of each presented at a meeting of the Linnean Society
both credited with the idea of natural selection

30. Darwin gets Busy! Write “short” version of his ideas
Includes evidence from
His insights into insects and other organisms
Distribution of organisms
Fossil record
Embryology
Comparative anatomy
Comparative behavior
and, and, and
Darwin at Down House, ca. 1880

31. November 24, 1859 First edition sells out the first day
Acceptance in scientific circles is rapid
Makes no reference to evolution of humans ON
THE ORIGIN OF SPECIES
BY MEANS OF NATURAL SELECTION,
OR THE
PRESERVATION OF FAVOURED RACES IN THE STRUGGLE
FOR LIFE.
BY CHARLES DARWIN, MA.,
FELLOW OF THE ROYAL, GEOLOGICAL, LINNAEAN, ETC., SOCIETIES; AUTHOR OF 'JOURNAL OF RESERACHES DURING H.M.S. BEAGLE'S VOYAGE ROUND THE WORLD.'
LONDON :
JOHN MURRAY, ALBEMARLE STREET.
1859.

32. From the final paragraph…
“There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.”

33. Later Works
The Descent of Man, and Selection in Relation to Sex (1871)
The Formation of Vegetable Mould through the Action of Worms, with Observations on Their Habits (1881)

34. Keys Points of Natural Selection
At any one time, more individuals are born into a species than will survive
Each individual is unique (that is, different from the others)
Some of these differences may be advantageous in the environment in which the individual lives, while others may be disadvantageous
The individuals with the advantages are more likely to survive and reproduce than the individuals with the disadvantages
Over time, the advantageous traits become more common, and the disadvantageous traits become less common

35. Microevolution ...and there’s nothing controversial about that
Macroevolution …if the process continues long enough, you can end up with entirely new species
And that’s what some people object to

36. Natural Artificial Two Types of Selection requires
a trait to exhibit variation
and a selective pressure
requires
a trait to exhibit variation
and a selective pressure
The selective pressure is exerted by humans
The selective pressure is exerted by the environment (nature)

37. The Three Problems
How is the variation present within a species at any time affected by the environment?
Darwin
How is variation passed on from one generation to the next?
Where does variation come from?

38. The Next Piece of the Puzzle
Gregor Mendel and
The Mechanisms of Inheritance

39. Gregor Mendel
Entered the Augustinian monastery of St. Thomas at Brnø at 22
Ordained as priest in 1847
Taught secondary school science

40. Two ideas about inheritance
Particulate
If you bred a white- flowered plant with a red-flowered plant, you will obtain a plant with either white or red flowers
Blending
If you bred a white- flowered plant with a red-flowered plant, you will obtain a plant with pinkish flowers

41. Pisum sativum Trait Forms seed form smooth wrinkled albumen color
yellow
green
seed coat color
gray
white
seed pod form
inflated
constricted
unripe pod color
flower position
axial
terminal
stem length
tall
dwarf

42. What Mendel Discovered
Each plant contained two pieces of information for a particular trait
Some of these were dominant, some recessive
Each parent contributed only one piece of information to each of their offspring

43. Gene – unit of hereditary information for a particular trait
Some terms…
Gene – unit of hereditary information for a particular trait
Allele – alternate form of a gene
Gamete – a sex cell (egg for females; sperm, pollen for males)

44. Pisum sativum genes alleles Trait Dominant Recessive seed form smooth
wrinkled
albumen color
yellow
green
seed coat color
gray
white
seed pod form
inflated
constricted
unripe pod color
flower position
axial
terminal
stem length
tall
dwarf

45. The Principle of Segregation
Mendel’s First Law
The Principle of Segregation
Alleles exist in pairs which are separated from one another during the production of gametes

46. …the chances of any particular outcome can be predicted!!!
this means that…
…the chances of any particular outcome can be predicted!!!

47. Inheritance occurs according to statistical probabilities!

48. The Principle of Independent Assortment
Mendel’s Second Law
The Principle of Independent Assortment
The distribution of alleles for one trait does not affect the distribution of alleles for another trait

49. Independent Assortment
Whether an individual inherited one particular trait from its father did not affect whether it inherited a different trait from the father as well
It’s a crapshoot!

50. The Synthetic Theory of Evolution
Variation is passed down according to Mendelian principles
and selected for or against according to Darwinian principles

51. What are the physical mechanisms through which traits are passed on?

52. Particulate or Blending?
The answer depends upon:
the trait being studied
the species it is being studied in

53. Over 4500 known “particulate” traits
In Humans?
Over 4500 known “particulate” traits
ABO blood group
Rh blood group
Cystic fibrosis
Cerumen
Sickle-cell
PTC tasting
Numerous
“blended” traits
Height
Weight
Intelligence
Skin color
Eye color

54. The Three Problems
How is the variation present within a species at any time affected by the environment?
Darwin
How is variation passed on from one generation to the next?
Mendel
Where does variation come from?