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ATH241 WSU Fa08
Introduction to Physical Anthropology
Tu & Th 10:25-12:05 Room 148 Russ
Anthropology Lab 065 Millett Hall
J.A. Coate, PhD
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Subclass: Theria
Infraclass: Eutheria
Cohort: Unguiculata
Order: Primates
Suborder: Haplorrhini
Infraorder: Simiiformes
Parvorder: Catarrhini
Superfamily: Hominoidea
Family: Hominidae
Subfamily: Homininae
Tribe: Hominini
Genus: Homo
Species: sapiens
Traditional, Pre-molecular, Paraphyletic
Pongo Gorilla
Pan
Pongidae
Homo
Hominidae
Hominoidea
Cladistics influenced, Molecular/Morphological,
Monophyletic
Pongo
G.
Pan
Panina
Homo
Hominina
Hominini
Ponginae
Homininae
Hominidae
chimps
Present
TIME
Fossil Record
?
~5-8 MYA
humans
Ardipithecus kadabba
5.2-5.8 Mya
Middle Awash,
Ethiopia
Present
TIME
Genetic Record
~5-8 MYA
chimps
humans
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Evolution and faith-based alternatives
+ Evolution is highly
misunderstood
+ Not necessarily mutually
exclusively
+ Unnecessary controversy
+ “Evolution is just a theory.”
“Yeah, I know; So is gravity.”
+ Without evolution, nothing in
biology makes sense.
Development of Evolutionary
Theory
Pre-Evolutionary people and ideas
• Scala naturae or Great chain of being; organisms
were immutable, i.e. “fixity of species” and seen as
types or essences.
• Other cultures had ideas of biological change but no
cohesive mechanism or theory.
• 1492 New World discovered by Western Europe
• Later Trans-oceanic voyages revealed incredible
biodiversity.
• Copernicus, 1514 ‘heliocentric’ solar system not
‘geocentric’
• Later restated by Galileo in the early 1600s.
• During this time the earth was thought to be only a
few thousand years old.
Pre-Evolutionary people and ideas
• Ray (1627-1705) : exclusive mating and fertile
offspring, used genus and species categories
separately.
• Linnaeus (1707-1778) : standardized Ray’s genus and
species categories creating binomial nomenclature,
placed humans in animal classification; however, he
was very religious.
• Buffon (1707-1788) : strong relationship between the
changing environment and organism but did not
believe species could give rise to another species.
• E. Darwin (1731-1802; Charles Darwin’s
grandfather) : life had originated in the seas, vast
expanse of time and all species descended from a
common ancestor.
Pre-Evolutionary people and ideas
• Lamarck (1744-1829) : “biology” and stressed
importance between species and environment; offered
an [incorrect] explanation as to how change in species
occurs, i.e. “inheritance of acquired characteristics”
or “use-disuse theory”.
• Cuvier (1769-1832) : extinction and catastrophism.
• Malthus (1766-1834) : “population size increases
exponentially while food supplies remain relatively
stable”.
Pre-Evolutionary people and ideas
• Lyell (1797-1875) : father of modern geology
and developed uniformitarianism (“the theory
that the earth’s features are the result of longterm processes that continue to operate in the
present as they did in the past…This theory
contributed strongly to the concept of immense
geological time” p. 27. E.g. erosion, glaciers,
island and mountain building, etc.
• Mary Anning (1799-1847) : “fossilist”
Discovery of natural selection
• C. Darwin (1809-1882) : HMS Beagle (1831-1836); natural
selection and compiled large amounts of biological evidence.
• A. Wallace (1823-1913) : independently develops natural
selection
• 1838 Darwin reads essay by Malthus.
• 1855 Wallace publishes paper which discusses how species are
descended from other species; this compels Darwin to publish.
• 1858 papers by Darwin and Wallace were read before the
Linnean society in London, neither author was present.
• On the origin of species, 1859
• G. Mendel (1822-1884) : genetics
Natural Selection
Natural Selection – “Genetic change or changes in the frequencies of certain
traits in populations due to differential reproductive success between
individuals”
The basic processes of evolution, as Darwin understood them, are as follows…
1. All species can produce species faster than the rate of
food production (from Malthus).
2. Biological Variation, both genetically and phenotypically
(from immunity to internal organs and external
appearance).
3. Competition for limited resources and mates; ‘struggle for
existence’ (from Lyell and Malthus).
4. Organisms with favorable traits have a more likelihood a
of survival and reproduction (i.e. survival of the fittest).
Normal distribution: the bell curve
Processes of Natural Selection
5. Environmental context determines whether or not a
trait is beneficial (E.g. the peppered moth).
6. Traits are inherited and passed on to the next
generation.
7. After large amounts of time and variation, descendant
generations can be quite distinct from their former
ancestors (i.e. descent with modification).
8. Geographic isolation contributes to formation of new
species, particularly on islands.
Natural selection in action
•
•
•
•
The peppered moth
Finches of the Galapagos Islands
Bighorn mountain sheep (see Weiner)
Consider also drug-resistant diseases or
pesticide-resistant insects.
Fundamentals of Evolutionary change brought
about by Natural Selection
1. “A trait must be inherited if natural selection
is to act on it (e.g. finch beak size; see
Weiner).
2. Natural selection can’t occur without
population variation in inherited
characteristics. Selection can only work with
variation that already exists (remember rule of
large numbers and a normal distribution).
Fundamentals of Evolutionary change brought
about by Natural Selection
3. Fitness (differential reproductive success) is a
relative measure that changes as the
environment changes. (e.g. peppered moth)
4. Natural selection can only act on traits that
affect reproduction” p. 34-35.
Constraints on 19th century
evolutionary theory
• Genetics and inheritance unknown during this
time.
• The work of Mendel not appreciated until the
early 1900s.
• The evolutionary synthesis of the 1930s-1940s
saw the merging of genetics and natural
selection.
Opposition to evolution
• Since the publication of “The origin of species” there has been
incredible debate.
• E.g. the Scopes monkey trial in Tennessee, 1925
• Why?
• Mechanisms of evolution are complex.
• Many people are not taught biology or genetics or
paleontology.
• Science and religion both explain phenomena differently;
• Science involves data analysis, hypothesis testing and
interpretation;
• Religion offers a system of beliefs based on faith which are
not amenable to scientific testing.
Key concepts of Evolution:
• Reproductive success – “The number of
offspring an individual produces and rears to
reproductive age; an individual’s genetic
contribution to the next generation” p. 32.
• Selective pressures - “Forces in the
environment that influence reproductive
success in individuals” p. 33. E.g. climate,
food and mate availability, predation, disease,
etc.
Key concepts of Evolution:
• Fitness – “A measure of relative reproductive
success of individuals. Fitness can be
measured by an individual’s genetic
contribution to the next generation compared
to that of other individuals” p.35.
• Adaptation – “Functional response (may be
physical or behavioral) of an organism or
populations to the environment. Adaptation
results from evolutionary change (specifically
as a result of natural selection)” p. 400.
Key concepts of Evolution:
• Ontogeny (growth and development) and
Phylogeny (evolutionary history).
• Genotype (the genetic code) and Phenotype
(the physical organism).
• Gene flow (genetic admixture) and genetic
drift (or founder effect; random fluctuations in
allele frequencies).
• Mutation (alteration of the genetic code)
• Morphology (the 3-d shape of a organ,
structure or functional complex)
Key concepts of Evolution:
• Anagenesis (or phyletic evolution) and
Cladogenesis (or divergent evolution)
• Microevolution and Macroevolution
• Sexual selection: E.g. coloration of male and
female birds.
• Artificial selection: domesticated animals and
plants.
Types of reproduction:
• K-selected: An adaptive strategy whereby
individuals produce relatively few offspring in
whom they invest increased parental care (e.g.
humans).
• r-selected: An adaptive strategy that
emphasizes relatively large numbers of
offspring and reduced parent care (e.g. mice or
fish or coral).
Readings
• #1 Shermer – Vestigial remains.
• #3 Weiner – evolution in action, sockeye salmon,
bacteria.
• #4 Rennie – the weakness of creationist arguments;
there are several transitional fossils.
• #5 Alters & Alters – evolution provides a unifying
theory for science; and several other disciplines
(biology, geology, paleontology, chemistry, genetics,
etc.) have all converged on similar conclusions.