Transcript Evolution_2

HMS Beagle
• Born 12 Feb 1809
• Medicine (Edinburgh University),
Theology (Cambridge)
• 1859, publication of The Origin of Species
http://en.wikipedia.org/wiki/Evolution
http://www.picturehistory.com/product/id/15157
• The second voyage of HMS Beagle from 27 December
1831 to 2 October 1836 was the second survey expedition of
HMS Beagle
• Captain Robert FitzRoy accompanied by a student
clergyman Charles Darwin
• Darwin made his name as a naturalist and became a
renowned author with the publication of his journal which
became known as The Voyage of the Beagle.
• The Beagle sailed across the Atlantic Ocean then carried
out detailed hydrographic surveys around the coasts of the
southern part of South America, returning via Tahiti and
Australia having circumnavigated the Earth. While the
expedition was originally planned to last two years, it lasted
almost five.
The Galapagos Account
“The natural history of these islands is
eminently curious, and well deserves
attention. Most of the organic productions
are aboriginal creations, found nowhere
else; there is even a difference between the
inhabitants of the different islands; yet all
show a marked relationship with those of
America, though separated from that
continent by an open space of ocean,
between 500 and 600 miles in width. The
archipelago is a little world within itself, or
rather a satellite attached to America,
whence it has derived a few stray colonists,
and has received the general character of its
indigenous productions.”
“The Beagle sailed round Chatham Island, and anchored in several bays. One night I slept on
shore on a part of the island, where black truncated cones were extraordinarily numerous:
from one small eminence I counted sixty of them, all surmounted by craters more or less
perfect. The greater number consisted merely of a ring of red scoriae or slags, cemented
together: and their height above the plain of lava was not more than from fifty to a hundred
feet; none had been very lately active.”
Download The Voyage of The Beagle from Project Gutenberg http://www.gutenberg.org/wiki/Main_Page
We will now turn to the order of reptiles,
which gives the most striking character to the
zoology of these islands. The species are not
numerous, but the numbers of individuals
of each species are extraordinarily great.
Darwin’s Checklist
1. Frogs – none!
2. Toads – none!
3. Lizards
4. Tortoises
“I have not as yet noticed by far the most
remarkable feature in the natural history of this
archipelago; it is, that the different islands to a
considerable extent are inhabited by a different
set of beings. My attention was first called to
this fact by the Vice-Governor, Mr. Lawson,
declaring that the tortoises differed from the
different islands, and that he could with certainty
tell from which island any one was brought.”
http://www.honoluluzoo.org/galapagos_tortoise.htm
Nesting Activity
Diet Adaptation
“When on board H.M.S. Beagle, as naturalist, I was much struck
with certain facts in the distribution of the organic beings
inhabiting South America, and in the geological relations of the
present to the past inhabitants of that continent. These facts, as
will be seen in the latter chapters of this volume, seemed to throw
some light on the origin of species—that mystery of mysteries, as
it has been called by one of our greatest philosophers. On my
return home, it occurred to me, in 1837, that something might
perhaps be made out on this question by patiently accumulating
and reflecting on all sorts of facts which could possibly have
any bearing on it. After five years' work I allowed myself to
speculate on the subject, and drew up some short notes;”
Introduction, “The Origin of The Species”
http://en.wikipedia.org/wiki/The_Origin_of_Species
Natural Selection
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Predator-Prey
Survival of the Fittest
http://www.essexwt.org.uk/leaflets/bee_gardening.htm
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http://www.defenders.org/wildlife_and_habitat
/wildlife/wolf,_gray.php
Transmission of
Traits
We behold the face of nature bright with gladness, we often see superabundance
of food; we do not see or we forget that the birds which are idly singing
round us mostly live on insects or seeds, and are thus constantly
destroying life; or we forget how largely these songsters, or their eggs,
or their nestlings, are destroyed by birds and beasts of prey; we do not
always bear in mind, that, though food may be now superabundant, it is not
so at all seasons of each recurring year.”
Darwin, on discussing the struggle for existence in The Origin of Species
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lions and gazelles
birds and insects
pandas and eucalyptus trees
Venus fly traps and flies
To keep our model simple,
we will make some
assumptions that
would be unrealistic in
most of these predatorprey situations.
1. the predator species is
totally dependent on a
single prey species as
its only food supply,
2. the prey species has an
unlimited food supply,
and
3. there is no threat to the
prey other than the
specific predator.
http://www.math.duke.edu/education/ccp/materials/diffeq/predprey/pred1.html
Percentages of predators in the Fiume fish catch
1914 1915 1916 1917 1918 1919 1920 1921 1922 1923
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Vito Volterra (1860-1940) was a famous Italian mathematician
who retired from a distinguished career in pure mathematics in
the early 1920s. His son-in-law, Humberto D'Ancona, was a
biologist who studied the populations of various species of fish
in the Adriatic Sea. In 1926 D'Ancona completed a statistical
study of the numbers of each species sold on the fish markets
of three ports: Fiume, Trieste, and Venice. The percentages of
predator species (sharks, skates, rays, etc.) in the Fiume catch are
shown in the above table. Alfred J. Lotka (1880-1949) was an
American mathematical biologist (and later actuary) who
formulated many of the same models as Volterra, independently
and at about the same time. His primary example of a predatorprey system comprised a plant population and an herbivorous
animal dependent on that plant for food.
http://www.math.duke.edu/education/ccp/materials/diffeq/predprey/pred2.html
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http://www-groups.dcs.stand.ac.uk/~history/PictDisplay/Volterra.html
Prey Population = x(t)
No predators: dx/dt = a x
Predators exist: Predator Population = y(t)
Encounters jointly proportional to xy :
Thus  dx/dt = ax – bxy
Let’s consider the predators y(t).
No prey means: dy/dt = cy
But with food…
dy/dt = cy + pxy
dx/dt = ax – bxy
dy/dt = cy + pxy