Lecture 6 - Evolution
- Have humans evolved from vastly simpler
organisms?
- Have other animals and plants evolved
from vastly simpler organisms?
- Does a belief in evolution lead to
dire theological, moral and social consequences?
- Can a Christian believe in evolution
and still be a "good Christian"?
- Does it matter whether we regard
evolution as a "fact" or merely a "theory"?
EVOLUTION
Big bang -> galaxies -> solar
system -> earth -> chemical
reactions in early atmosphere
->
amino acids -> proteins-> DNA -> single cell -> more
complex ->humans
organisms organisms
God acts at certain points??
There is evidence for life about 4 Gy
ago (Pilbara, WA) - so time for chemical reactions short!
To synthesise protein, need chain of
amino acids in specific order in DNA. - 3 DNA 'letters' for each
amino acid. So protein with 100 amino acids needs 300 letters-long
DNA.
One chance in 10130 for this to occur
randomly. Completely unlikely in 500My.
- assemble in some ordered way?
Michael Denton - "A theory in crisis"
Major discontinuities hard to explain
- e.g.
- primitive terrestrial mammal ->
whale
- primitive terrestrial reptile ->
Ichthyosaur
Need long lineages for very different
creatures.
Theory of Evolution (Selkirk and Burrows):
"The origin of life from prebiotic substances
and the subsequent differentiation through time of all species from
pre-existing species, this ongoing process being the result of changes
produced by natural selection and/or mutation in the genetic makeup
of populations".
5 concepts:
- Overproduction of young. Smaller
organisms overproduce more. viruses (millions) -> elephants
(10).
- Variation and its heritability. No
offspring identical and differences inherited.
- Natural selection. Some variations
compete more successfully.
- Change through time. Mutations ->
random changes - "genetic drift".
- Speciation. Isolated groups develop
separately until they are unable to interbreed.
Evidences
Micro-evolution - whipbirds, peppered
moth in industrial England,.
Hawaiian fruit flies.
Nucleotide sequences in mammals.
Fossil strata.
Punctuated equilibrium theory - speciation
occurs over thousands to tens thousands years. Then follows millions
of years of no change - stasis.
There are different details in
evolutionary theories.
Archaeopteryx - link between reptiles
and birds - reptile-like body + feathers.
No significant fossil hominids found
till 1893 - 'Java Man'
1924 discovery of Australopithecus "Lucy"
- link to Homo.
Religious belief (burial) in Neanderthals
- 70 000 y bp.
Chimpanzees have biochemical similarity
to humans - differ only in 0.8% of 40 blood proteins studied - common
ancestor about 6My ago.
Alfred Russel Wallace: "How did man
get his brain?" - theological answer.
South seas natives - large brain, intelligence
- more than required.
Frontal cortex
- 3.5% of cortex in rats
- 17% in chimpanzees
- 29% in humans.
Governs essential feature of human-ness,
godliness? Expanded/evolved most recently.
Chimpanzee - human DNA similar but brain,
stooping different. Neoteny - maturation slowdown. Not detectable
in DNA - inbuilt algorithm.
Human brain doubles in size in 1st yr,
+25% in 2nd yr, +15% in 3rd yr.
Eiseley's description of discovery in
French cave near La Chapelle-aux-Saints in 1908.
Sufi Islam: Doctrine of gradation of
beings. - metaphysical principle.
Hierarchy:
lowest material form -> man ->
God
Polkinghorne - "fruitfulness" of creation.
Theistic evolution
- just laws of physics?
- God guides evolution?
Falconer: dolphins on same evolutionary
track as us?
Some Evolution Article Links
Further
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