Transcript Darwin and Evolution

Darwin and Evolution
Charles Darwin 1809-1882
Young Darwin
H.M.S. Beagle
Captain Fitzroy, commander of the Beagle.
Very conscious of the stressful loneliness of
command and of the suicide both of Captain
Stokes and of his uncle Viscount Castlereagh,
who had cut his own throat in 1822 while in
government office, he approached Beaufort in
August 1831 and asked him to find a suitable
gentleman companion for the voyage. Such a
companion should share his scientific tastes,
make good use of the expedition's opportunities
for naturalism research, dine with him as an
equal, and provide a semblance of normal human
friendship.[1] While those Beaufort first
approached turned the opportunity down, FitzRoy
eventually approved Charles Darwin for the
position. Before they left England FitzRoy gave
Darwin a copy of the first volume of Charles Lyell's
Principles of Geology, a book the captain had
read that explained terrestrial features as the
outcome of a gradual process taking place over
extremely long periods.
- The crew of the Beagle hailed by Fuegians of
Jemmy Button's tribe. Orundellico, known as
"Jemmy Button", (c.1815-1864) was a native
Fuegian of the Yaghan (or Yamana) tribe from
islands around Tierra del Fuego, in modern
Chile and Argentina. He was brought to
England by Captain FitzRoy on the HMS
Beagle and became a celebrity for a period.
In 1830, Captain Robert FitzRoy, at the command of the first expedition of the famous
Beagle, took a group of hostages from the Fuegian indigenous people after one of his boats
was stolen. Jemmy Button was paid for with a mother of pearl button, hence his name. It is
not clear whether his family willingly accepted the sale or he was simply abducted. FitzRoy
decided to take four of the young Fuegian hostages all the way to England "to become
useful as interpreters, and be the means of establishing a friendly disposition towards
Englishmen on the part of their countrymen."[1] He seems to have shown great concern for
the four, feeding them before his own officers and crew and intending them to be educated
and Christianised so that they could improve the conditions of their kin.
One year later, the Beagle returned the three surviving Fuegians home, still captained by
FitzRoy and at great expense to himself. He took with him a young naturalist, Charles
Darwin, in what was the second voyage of HMS Beagle.
After initial difficulty recalling his language and customs, Jemmy was soon out of his
European clothes and habits. A few months after his arrival, he was seen emaciated, naked
save for a loincloth and long-haired. Nevertheless, he declined the offer to return to England,
which Darwin conjectured was due to the presence of his "young and nice looking wife",
Lassaweea. It appears that he and the others had taught their families some English
FitzRoy's account includes a section of Remarks with reference to the Deluge in
which he admits that having read works "by geologists who contradict, by
implication, if not in plain terms, the authenticity of the Scriptures" and "while led
away by sceptical ideas" he had remarked to a friend that the vast plain of
sedimentary material they were crossing "could never have been effected by a forty
days' flood" indicating that in his "turn of mind and ignorance of scripture" he was
willing to disbelieve the Biblical account. Concerned that such ideas might "reach
the eyes of young sailors" he earnestly explains in great detail his renewed
commitment to a literal reading of the Bible, with arguments that rock layers high in
the mountains containing sea shells are actually proof of Noah's Flood and that the
six days of creation could not have extended over aeons because the grass, herbs
and trees would have died out during the long nights.[5]
When The Origin of Species was published FitzRoy was dismayed and
apparently felt guilty for his part in the theory's development. He was in Oxford on
30 June 1860 to present a paper on storms and attended the meeting of the
British Association for the Advancement of Science at which Samuel Wilberforce
attacked Darwin's theory. During the debate FitzRoy, seen as "a grey haired
Roman nosed elderly gentleman", stood in the centre of the audience and "lifting
an immense Bible first with both and afterwards with one hand over his head,
solemnly implored the audience to believe God rather than man". As he admitted
that The Origin of Species had given him "acutest pain", the crowd shouted him
down
Voyage of the Beagle. 1831-1836
Thomas Malthus, 1766 - 1834
Alfred Wallace was a famous biologist and
zoogeographer. He is known as the father
of biogeography. Alfred Wallace was born
in England 1823, and died in 1913. In
1848, he went on an expedition with Henry
Walter Bates to the Amazon. Between
1854 and 1862 he conducted research on
the Malay archipelago. During the
expedition, he noticed striking zoological
differences between animal species of Asia
and Australia. He created an imaginary
line called Wallace's Line to explain these
differences. In a striking coincidence, in
1858 Wallace wrote to another British
biologist named Charles Robert Darwin
about his ideas of evolution. Darwin had
come up with the same theory of evolution.
In 1858 Wallace’s contribution was entitled
“On the tendency of varieties to depart
indefinitely from the original type”. His work
describes the theory of natural selection.
Darwin’s Theory
Species Over-reproduce
High mortality
Survival of most fit
+
+
+
population sizes remain constant
universal variation
environmental change
change through time = Evolution
Problems
How to reconstitute variation??
answer, comes after 1900 with discovery of genetics – see next lecture
Response to Darwin
Fact of Evolution vs Theory of Evolution
Theory = what was the mechanism?
Fact = did evolution occur? Accepted by most soon after publication
Fact accepted because it explained a lot of observations
fossil record
Neanderthals
embryology
transitional forms.
Theodosius Dobzhansky: “Nothing makes sense except in the light of
Evolution
Horse evolution,
Western U.S.
Neanderthal
Human embryo; gill clefts, notochord,
tail,
The Theory: not proven due to lack of understanding of variation.
But: accepted anyway
1. Religious acceptance, the two revelations; the world and the book
2. Political acceptance; the “white man’s burden”, favored races
3. Social acceptance: Herbert Spencer and charity
Karl Marx and class struggle
4. Economic acceptance: capitalism
Backlash: cooperation vs competition = struggle for existence vs cooperation
Note: what does survival of the fittest mean??
a) Nature red of tooth and claw = struggle?
b) Differential reproduction – having more offspring.
college professors vs “lower educational levels”
Los Angeles – Hispanic vs other Caucasians
- Israelis vs Palestinians
Is this good or bad?? Depends on the causes of differences
between the groups
Are they different due to genes, or economics, or opportunities?
Scientific response to Darwin
1. Fact accepted quickly (except for a few)
2. Theory – With the discovery of Genetics (1900) = impressed by mutation
Hopeful monsters = new species or group in one generation without
selection!!
Problems:
a. Monsters don’t mate
b. Monsters don’t function very well
Due to extra segment = hox gene duplication; can’ t fly =
non functional
Early paleontologists questions: 1. rate appears to be constant
2. how can a small change be selected for?
Early Paleontology -
Paleontology - rate of change
through time appears constant
a. – finalism
b. Vitalism
Incorporates the idea that evolution has a goal
towards which it is progressing (guess what that
goal is!)
The Synthesis - 1945 – genetics and paleontology come together.
a. Genetics provides the variation – even small variation can be selected for
b. Selection (the environment) determines what survives.
Note: environmental change irregular
And: no goal or direction to evolution other than adaptation.
New concepts
Punctuated equilibrium = differences in rate. Fast and slow.