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The origin and design of life

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Title: The origin and design of life


1
The origin and design of life
2
Outline
  • Evolutionary theory
  • What are organisms?
  • Natural Selection vs. Intelligent Design

3
Logic of Darwins argument
  • Natural populations could grow exponentially

4
Exponential growth
5
Logic of Darwins argument
  • Despite this potential for exponential growth,
    natural populations normally are relatively
    stable
  • Many individuals do not leave as many offspring
    as they might
  • Those best suited to the prevailing environment
    will leave the most offspring (i.e. the best
    fit to the environment

6
Logic of Darwins argument
  • Because of heredity, offspring are like their
    parents
  • Over many generations, natural selection builds
    individuals that are progressively better adapted
    to their environment

7
Natural Selection
  • 3 essential components
  • Variation
  • Inheritance
  • Selection
  • Differential reproductive success
  • Over time, natural selection produces designs for
    reproduction (adaptations)

8
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9
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10
The easy way
  • Imagine a gene that happens to make an organism
    more likely to be X.
  • Would that gene become more common in the next
    generation?
  • If yes, it will be selected for and we should
    look for it in nature.
  • If no, it will disappear and shouldnt be found
    in nature.

11
Two general approaches
  • Phylogenetic approach organisms are related to
    each other by virtue of common descent
  • Searches for features that are similar because
    both species inherited them from a common
    ancestor
  • Adaptationist approach organisms have particular
    design features by virtue of their unique
    evolutionary histories
  • Explores how natural selection functionally
    organizes the design of organisms can be applied
    to unique features

12
Phylogenetic approachWho are you?
  • Kingdom Animalia
  • Phylum Chordata
  • Subphylum Vertebrata
  • Class Mammalia
  • Order Primate
  • Family Hominidae (includes Homo erectus)
  • Genus Homo
  • Species Sapiens
  • Subspecies sapiens (not neanderthalenis)

13
An evolutionary tree of primates based on DNA
evidence
after Goldsmith Zimmerman (2001)
14
Adaptation Products of Evolution
  • Organisms are composed of the following three
    features
  • Adaptations (design features)
  • Solve particular adaptive problems (i.e.
    selection pressures)
  • By-products
  • Noise
  • Can apply this classification to features of
    man-made artifacts as well

15
Adaptations (design features)
  • Inherited and reliably developing characteristics
    that come into existence through natural
    selection because they helped to solve problems
    of reproduction during the period of their
    evolution (i.e., in the EEA)
  • EEA Environment of Evolutionary Adaptedness
  • E.g., umbilical cord

16
Adaptive problem
  • Anything that affects reproduction
  • E.g., finding food, avoiding predators, fighting
    disease, competing or cooperating with
    conspecifics, finding a mate, giving birth,
    raising an offspring
  • Had to recur across many generations
  • Its solution had to affect reproduction, however
    indirectly

17
Features of adaptations
  • Reliably developing
  • Specialized
  • Show evidence of design
  • Adapted to ancestral environments

18
By-products
  • Characteristics that do not solve adaptive
    problems and do not have functional design they
    are carried along with characteristics that do
    have functional design because they happen to be
    coupled with those adaptations
  • E.g., belly button

19
Noise
  • Random effects produced by forces such as chance
    mutations, sudden and unprecedented changes in
    the environment, or chance effects during
    development
  • E.g., particular shape of a persons belly button

20
Life Machinery
  • Natural selection provides a causal explanation
    of design
  • The organism is a self-reproducing machine.

21
Structure reflects function
  • Organisms are highly ordered entities
  • Organization comes from natural selection
  • Chance processes act to randomize relationships
    within organism
  • Superhero problem
  • Bunny in the blender
  • Natural selection is NOT chance

22
  • Natural selection is a feedback process
  • Design modifications that improve reproduction
    spread throughout the population

23
Biological functionality is weird
  • In evolutionary theory, to say a feature was
    adaptive means that, in the environment in which
    that feature evolved, that feature promoted its
    own reproduction
  • Adaptive does NOT mean
  • Beneficial in terms of well-being, health,
    happiness or other human values
  • Good for the species, group, or even individual
  • The feature is desirable or inevitable
  • Nature is indifferent, not cruel or benevolent

24
Test yourself
  • How do fruits and vegetables reproduce?
  • Fruit Vegetables
  • Edible?
  • Cook?
  • Sugar?
  • Toxins?
  • Colors?
  • Defenses?

Almost all A few None Most High Very low
Low High Bright Camouflaged Pesticide Pesti
cide, poison, thorns, bark
25
Natural Selection, Intelligent Design
Creationism
26
Caveat Why bother?
  • Reasons not to teach ID or Creationism
  • Can be offensive to the religious
  • You hear enough bashing of conservatism
  • Theres no real debate we dont teach
    astrology, e.g.
  • Reasons to teach the controversy
  • Expose the lack of actual controversy
  • Brings to light evidence you wouldnt otherwise
    see
  • Educate those who dont know the main arguments
  • They asked for it

27
Data in support of Natural Selection
  • comparative morphology (e.g. hands on whales)
  • fossil record of transitional forms
  • Carbon, Potassium-Argon dating of those forms
  • mDNA clocks dating of those forms
  • geological evidence supporting timing of those
    forms
  • comparative embryology
  • all life come from their own kind (unlike all
    tools)
  • all life shares same biochemical background
  • vestigial organs (e.g. man-nipples fingernails)
  • NO species designed for non-reciprocal aid of
    another
  • design flaws (e.g. backward retina)

28
Flawed Design examples in humans
29
Data in support of Natural Selection
  • 50/50 sex ratio
  • Inter-species conflict
  • Intra-species conflict
  • Intra-genomic conflict
  • visible mutations
  • visible inheritance

30
Data in support of Natural Selection
  • mathematical certainty of natural selection given
    mutations and inheritance
  • behavioral patterns in hundreds of species
    indicating design for reproduction
  • blurred lines between species, e.g. donkey/mule,
    wolf/pug
  • creation of different species through
    artificial selection, e.g. nuclear bacteria
  • watching natural selection take place (e.g.
    sickle cell anemia, resistant bacteria, lactose
    tolerance)
  • Etc.

31
Percentages of people with lactose intolerance
32
Intelligent Design advocates say
  • Irreducible complexity
  • By irreducibly complex I mean a single system
    composed of several well-matched, interacting
    parts that contribute to the basic function,
    wherein the removal of any one of the parts
    causes the system to effectively cease
    functioning. Michael Behe
  • How could natural selection design this?
  • E.g. a mousetrap, a single-cell organism?
  • If it requires all functional parts at once,
    natural selection cant design itright?
  • Therefore, some intelligent being designed it

33
Intelligent Design
  • Three kinds of ID
  • Creationism
  • Design of species
  • no whale transitional forms
  • First causes
  • ID happened billions of years ago

34
Magic Trick Fallacy
  • http//www.youtube.com/watch?vUYTmEVFL_NA
  • Intelligent Design works like magicians
  • Your theory fails to explain some stuff
  • Therefore, my theory is right
  • Problem?
  • Its not enough that we are wrong, YOU have to be
    right.

35
Data in support of Intelligent Design
  • None
  • ID doesnt make predictions.
  • Thesis of ID Someone did something somehow at
    some time that natural selection cant explain.
  • ID doesnt make predictions
  • Creationism does

36
Creationism
  • Two creationist accounts in Genesis
  • Genesis 124. And God said, "Let the land
    produce living creatures according to their
    kinds livestock, creatures that move along the
    ground, and wild animals, each according to its
    kind." And it was so. (125) God made the wild
    animals according to their kinds, the livestock
    according to their kinds, and all the creatures
    that move along the ground according to their
    kinds. And God saw that it was good. (126)Then
    God said, "Let us make man in our image, in our
    likeness, and let them rule over the fish of the
    sea and the birds of the air, over the livestock,
    over all the earth, and over all the creatures
    that move along the ground."

37
Creationism
  • Genesis 218. And the LORD God said, It is not
    good that man should be alone I will make him a
    helper comparable to him. 219 Out of the ground
    the LORD God formed every beast of the field and
    every bird of the air, and brought them to Adam
    to see what he would call them. And whatever Adam
    called each living creature, that was its name.
    220 So Adam gave names to all cattle, to the
    birds of the air, and to every beast of the
    field. But for Adam there was not found a helper
    comparable to him.
  • 221 And the LORD God caused a deep sleep to fall
    on Adam, and he slept and He took one of his
    ribs, and closed up the flesh in its place. 222
    Then the rib which the LORD God had taken from
    man He made into a woman, and He brought her to
    the man.

38
Creationist account of animals
  • Account 1 suggests that animals should be
    designed for humans to lord over.
  • Account 2 suggests that animals should be
    designed for male companionship.

39
Data contradicting Creationism
  • Universe infinitely larger than necessary to
    house humans
  • Earth not designed for us
  • Worst possible shape for surface dwelling
    creature
  • More water on surface than land
  • Much of the land not hospitable
  • Earth has existed for billions of years, humans
    for 100,000
  • Immune system AND diseases?
  • Life appears to fight itself, which is
    inconsistent with single creator
  • Oxygen and breathing?
  • Physics structured in ways that introduce
    problems, then massive design to solve it.
    Whoever designed physics didnt do it for humans.

40
Data contradicting Creationism
  • Animals run away? Resist being eaten? Fight
    back?
  • If they are helpers or servants they shouldnt do
    that
  • Genesis 9 changes this, but reaffirms that
    Every creature that is alive shall be yours to
    eat.
  • Natural plants are high in useless toxins
  • Most plants are inedible because of toxins
    manufactured for that purpose
  • Most animals are highly inedible without great
    preparation
  • Only fruit seems well designed for consumption
  • and then only when the fruit can reproduce
  • Animals exist at the bottom of the ocean
  • Microscopic life?

41
Data contradicting Creationism
  • comparative morphology (e.g. hands on whales)
  • fossil record of transitional forms
  • Carbon, Potassium-Argon dating of those forms
  • mDNA clocks dating of those forms
  • geological evidence supporting timing of those
    forms
  • vestigial organs (e.g. man-nipples fingernails)
  • design flaws (e.g. backward retina)

42
What controversy?
  • The data is such that there is no debate between
    evolution and creationism among anthropologists,
    archaeologists, geologists, astrophysicists, or
    any other group of scientists.

43
Explaining Irreducible Complexity
  • Irreducibility can evolve after addition of new
    features.
  • Example of an irreducibly complex object

44
Explaining Irreducible Complexity
  • Bridge
  • Add better part
  • Remove useless part

45
Data contradicting Natural Selection
  • None.
  • After 150 years of the most vehement attacks any
    scientific theory has ever had there is not a
    single reliable data set contradicting natural
    selection
  • This doesnt mean we understand everything.
  • E.g. car manufacturing and the laws of physics

46
Nonsense about Natural Selection
  • An ant is less evolved than a monkey
  • It means less human like but thats silly
  • Survival of the species
  • Animals have instinct which has evolved and
    reason which hasnt
  • Evolution doesnt apply to humans because we
    learn.
  • learning is something natural selection
    designed animals to do
  • other animals learn

47
Conclusions
  • Natural selection created and designed life on
    earth into self-replicating machines.
  • Next time
  • Evolutionary Psychology how can an understanding
    of natural selection help us understand the
    workings of the human brain?

48
  • Readings for this week
  • Buss Ch. 1 2
  • No Section on first week
  • See me for add codes
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