Anthropology

1
Anthropology

• Chapters 1 2

2
What is Anthropology?

• From the Greek
• Anthropos man
• Logos study
• Anthropology is the study of man

3
Fields of Anthropology

• Biological (Physical) Anthropology
• Human paleontology a.k.a. paleoanthropology -
  studies the emergence and evolution of humans
• Human variation studies why contemporary human
  populations vary biologically
• Cultural Anthropology
• Archaeology - study of past cultures through
  material remains
• Anthropological linguistics study of languages
• Ethnology study of existing recent cultures
  (How why peoples today in the recent past
  differ in their customary ways of thinking
  acting e.g. marriage customs, political
  economic systems, religion, music, etc
  Ethnographers live in a population for at least a
  year observing their customs

4
How do we learn from hominids?

• Experimentation
• Physiological Science
• 1. How will a system respond
  
• to a disturbance?
• 2. Create the disturbance
• 3. Compare observations with
  
• expected results
• Comparison
• Evolutionary Science
• Comparative anatomy
• Molecular biology
• Cell biology

5
Anthropological Evolution

• The history of hominids (Present day extinct)

6
Phylogeny

• The history of hominid life depicted as a
  branching tree
• Earliest hominids are placed at the trunk
• Each branch represents a new species which
  inherits many traits from the ancestor but also
  has a new trait which appear for the 1st time

7
Phylogenetic Tree
8
Famous Quote

• It is not the strongest of the species that
  survive, nor the most intelligent, but the one
  most responsive to change.
• -Charles Darwin

9
Charles Darwin(1809-1882)

• Born in England
• Attended medical school, HATED IT, and dropped
  out to become a priest
• Boarded the H.M.S. Beagle for a 5 year UNPAID
  journey as a naturalist

10
Journey of the H.M.S. Beagle
11
Alfred Russel Wallace(1823-1913)
Presented a paper with identical ideas as Darwin
on July 1, 1858 at the Linnaean Society
meeting Was a botanist who came up with virtually
the same concept of natural selection more or
less independently through his studies on the
Malay archipelago. Darwin panicked because he was
not ready with his book yet!
12
Where did Darwin and Wallace get the idea of
evolution?
13
Jean Baptiste Lamarck (1744-1829)

• Lamarck claimed that evolution was driven by "use
  vs. disuse"
• A used structure will become larger, stronger and
  more important.
• A disused structure will atrophy and become
  VESTIGIAL.

14
Theory of Use vs. Disuse

• The long necks of giraffes were due to their
  stretching for food, and giraffes passed their
  stretched necks on to their offspring.

• Similarly, the big, ripped muscles developed by
  the village blacksmith with all his hammering and
  slinging of heavy metal objects would be expected
  to be passed on to his offspring.

15
Theory of Acquired Characteristics

• Lamarck claimed that traits acquired during an
  organism's lifetime could be inherited by that
  organism's offspring.

16
Georges Cuvier(1769-1832)

• Created Paleontology
• (The study of fossils)
• He noted that deeper layers of sedimentary rock
  had diversity of organisms far different from
  present day life found in more recent layers
• Proposed the idea of extinction based on fossils

17
James Hutton(1726-1797)

• A Scottish geologist who challenged Cuvier's view
  in 1795 with his idea of GRADUALISM
• Proposed that large changes in the earth's
  surface could be caused by slow, constant
  processes such as erosion.

18
Charles Lyell (1797-1875)

• Earth processes had been going on constantly, and
  could explain the appearance of the earth.
• This theory, uniformitarianism, was a strong
  basis for Darwin's later theory of natural
  selection.

19
Thomas Malthus(1766-1834)

• Suggested that much of humanity's suffering
  (disease, famine, homelessness and war) was the
  inevitable result of overpopulation humans
  reproduced more quickly than their food supply
  could support them.
• Malthus showed that populations, if allowed to
  grow unchecked, increase at a geometric rate.

20
Darwin made some profound observations, from
which he inferred some brilliant conclusions...

• Observation 1. All species have huge potential
  fertility
• Observation 2. Except for seasonal fluctuations,
  populations tend to maintain a stable size.
• Observation 3. Environmental resources are
  limited.

21
Inference 1

• The production of more individuals than the
  environment can support leads to a "struggle for
  existence," with only a fraction of offspring
  surviving in each generation.

22
Observations

• Observation 4 No two individuals in a
  population are exactly alike
• Observation 5 Much of the observed variation in
  a population is heritable

23
Inference 2

• Survival in this "struggle for existence is not
  random, but depends, in part, on the hereditary
  makeup of the survivors.
• Those individuals who inherit characteristics
  that allow them to best exploit their environment
  are likely to leave more offspring than
  individuals who are less well suited to their
  environment.

24
Inference 3

• Unequal reproduction between suited and unsuited
  organisms will eventually cause a gradual change
  in a population, with characteristics favorable
  to that particular environment accumulating over
  the generations.

25
SO WHAT IS THIS THEORY OF NATURAL SELECTION?

• It can be broken down into four basic tenets, or
  ideas

26
Theory of Natural Selection

• 1. Organisms are capable of producing huge
  numbers of offspring.
• 2. Those offspring are variable in appearance and
  function, and some of those variations are
  heritable.

27
Theory of Natural Selection

• 3. Environmental resources are limited, and those
  varied offspring must compete for their share.
• 4. Survival and reproduction of the varied
  offspring is not random. Those individuals whose
  inherited characteristics make them better able
  to compete for resources will live longer and
  leave more offspring than those not as able to
  compete for those limited resources.

28
Evolution

• Theory - an accepted hypothesis that has been
  tested over and over again without yet being
  disproved
• Definition - Evolution is the change in the
  overall genetic makeup of a population over time
• Three Basic Componentsa.  Individuals cannot
  evolve.  Populations evolve.b.  Natural
  selection is the mechanism of evolution.c. 
  Evolution occurs by chance.

29
Evolution

• Evolution is the genetic change in a population
  over time
• Populations are a group of interbreeding
  individuals belonging to the same species and
  sharing a common geographic area
• Natural selection favors individuals, so multiple
  generations must be examined

30
What is speciation and who studies it?

• Speciation is the creation of a new species
• Scientists who study the processes and mechanisms
  that lead to such speciation events are called
  EVOLUTIONARY BIOLOGISTS.

31
Allopatric Speciation

• A population becomes physically separated from
  the rest of the species by a geographical barrier
  that prevents interbreeding. 
• Because gene flow is disrupted by this physical
  barrier, new species will form.

32
Sympatric Speciation

• Two populations are geographically close to each
  other, but they are reproductively isolated from
  each other by different habitats, mating seasons,
  etc.

33
(No Transcript)
34
Reproductive Barriers

• A reproductive barrier is any factor that
  prevents two species from producing fertile
  hybrids, thus contributing to reproductive
  isolation.
• Habitat Isolation
• Temporal Isolation
• Behavioral Isolation
• Mechanical Isolation
• Gametic Isolation

35
(No Transcript)
36
(No Transcript)
37
Species

• A SPECIES is a group of similar organisms that
  can mate to produce fertile, viable offspring.
• Different species are, by definition,
  REPRODUCTIVELY ISOLATED from one another.

38
(No Transcript)
39
Adaptive Radiation

• Adaptive Radiation - Evolutionary process in
  which the original species gives rise to many new
  species, each of which is adapted to a new
  habitat and a new way of life.     E.g. Darwin's
  Finches 

40
(No Transcript)
41
Adaptive Radiation of Hominids
42
Evidence for Evolution

• HOMOLOGY is a characteristic shared by two
  species (or other taxa) that is similar because
  of common ancestry.
• Artificial Selection Farmers had been conducting
  this controlled breeding of livestock and crops
  for years in order to obtain the most milk from
  cows or the best cobs from corn plants.

43
Evidence for Evolution

• Paleontology - Study of Fossilsa.  Fossil -
  preserved evidence of past lifeb.  Radioactive
  Dating - method by which fossil age can be
  determined by the amount of organic matter
  remaining in the specimen.  This is possible
  because some substances break down at a known
  rate (half-life).

44
Types of homology

• morphological homology species placed in the
  same taxonomic category show anatomical
  similarities.
• ontogenetic homology - species placed in the same
  taxonomic category show developmental
  (embryological) similarities.
• molecular homology - species placed in the same
  taxonomic category show similarities in DNA and
  RNA.

45
MORPHOLOGICAL HOMOLOGY

• Structures derived from a common ancestral
  structure are called
• HOMOLOGOUS STRUCTURES

46
(No Transcript)
47
(No Transcript)
48

49
(No Transcript)
50
Ontogenetic Homology

• The human embryo has gills, a tail, webbing
  between the toes fingers, spends its entire
  time floating and developing in amniotic fluid
  has similar salt concentration as ocean water

51
(No Transcript)
52
MORPHOLOGICAL HOMOLOGY

• A structure that serves the same function in two
  taxa, but is NOT derived from a common ancestral
  structure is said to be an
• ANALOGOUS STRUCTURE

53
(No Transcript)
54
Examples of Analogous structures

• wings of bat, bird, and butterfly
• walking limbs of insects and vertebrates
• cranium of vertebrates and exoskeleton head of
  insects

55
Molecular Homology
56
(No Transcript)
57
Types of Evolution

• Divergent Evolution - Method of evolution
  accounting for the presence of homologous
  structures.  Multiple species of organisms
  descended from the same common ancestor at some
  point in the past.
• Convergent Evolution - Method of evolution
  accounting for the presence of analogous
  structures.  Organisms of different species often
  live in similar environments, thus explaining the
  presence of features with similar functions.

58
(No Transcript)
59
An ongoing process

• Evolution can be considered a process of
  "remodeling" a population over the course of many
  generations, with the driving force being the
  natural selection factors that favor one form
  over another in specific environments.

60
Vestigial Structures

• Have marginal, if any use to the organisms in
  which they occur.
• EXAMPLES
• femurs in pythonid snakes and pelvis in cetaceans
  (whales)
• appendix in humans
• coccyx in great apes

61
(No Transcript)
62
(No Transcript)
63
Rate of Evolution

• Gradual evolution occurs where the increment of
  change is small compared to that of time.
• Punctuated evolution occurs where the increment
  of change is very large compared to that of time
  in discrete intervals, while most of the time
  there is virtually no change at all.

64
(No Transcript)
65
Natural Selection in Action

• Industrial melanism

66
Natural Selection in Action

• Camouflage

67
Natural Selection in Action

• Mimicry
• Coral vs. King Snakes Red on yellow, kill a
  fellow, red on black wont hurt Jack

68
Natural Selection in Action

• Mimicry
• Monarch or Viceroy Butterfly

69
Natural Selection in Action

• Warning Coloration

70
Causes of Evolution

• Mutations - random changes in genetic material at
  the level of the DNA nucleotides or entire
  chromosomes
• Natural Selection - most important cause of
  evolution measured in terms of an organism's
  fitness, which is its ability to produce
  surviving offspring
• a.  Stabilizing Selection - average
  phenotypes have a selective advantage over the
  extreme phenotypes
• b.  Directional Selection - phenotype at one
  extreme has a selective advantage over those at
  the other extreme
• c.  Disruptive Selection - both extreme
  phenotypes are favored over the intermediate
  phenotypes

71
Causes of Evolution

• 3. Mating Preferences - Organisms usually do not
  choose their mates at random, thus the selection
  process can cause evolution
• 4.  Gene Flow - Transfer of genes between
  different populations of organisms.  This
  situation leads to increased similarity between
  the two populations
• 5.  Genetic Drift (Founder Effect) - Situation
  that results in changes to a population's gene
  pool caused by random events, not natural
  selection.  This situation can have drastic
  effects on small populations of individuals. 
  Common on islands.

72
Causes of Evolution

• Bottleneck Effect
• Founder Effect

73
(No Transcript)
74
(No Transcript)
75
(No Transcript)
76
Hardy-Weinberg

• HW law states --gt original of a genotypes
  alleles remains CONSTANT
• HW Equilibrium... is defined algebraically
• any gene with 2 allelic forms... A and
  a
• let frequency of one allele (A) p
  frequency of other allele (a) q
• then by definition, p q 1
• HW equation... (p q)2
  p2 2 pq q2 1
• 
  GG Gg gg