Transcript Darwin_Ecology_and_Evolution

Darwin, Ecology, and
Evolution
Big “Rocks” of
science
• The origin of the
universe
• The origin of life
• The incredible
biological diversity of
today. Link
• The origin of human
consciousness.
Concepts in this Course
• An appreciation of the biological diversity, and
how vastly different organisms are related to
each other.
• The ability to read and write phylogenetic trees
to describe evolutionary relationship
• Understanding The Population Concept:
– populations and species evolve, individuals
do not
More Concepts in this Course
• The scientific nature of
evolutionary biology;
• The role of chance and
probability in evolution.
• How speciation by natural
selection works
– How natural selection works and
how to calculate evolutionary
change under several different
situations.
• Where does man fit it? Does
evolution affect man today?
Points to ponder from your reading
• Before Darwin,
biology was an
offshoot of theology
like most science
before 1800
Link
• Darwin supplied two important ideas that create a
pervasive undercurnt that affects all of biology
• Evolutionary descent with modification
• Direction of evolution by natural selection
“Darwin has obsessed, impressed and
Frustrated people for some time”
• Starting in the 19th
century, Darwinism had
a great deal of impact
on political and social
discussions Link
• Social Darwinism was
an Anglo-American
movement that argued
for the elimination of
the unfit from human
society link
Darwin was a liberal who hated
slavery and was concerned with
the suffering of the unfortunate
He was neither a communist or a
social Darwinist
The Myth and the Man
• Darwin was mostly a gentleman student
during his years in Cambridge. Video Link
– His father sent him to a boarding school and
paid for a first rate upper class education
– A Cambridge Darwin was very much a
“gentleman student”
– (he was a natural intellectual)
The voyage of the Beagle
• Darwin sailed around the world with the crew
of the Beagle from 1831 to 1836, sending
specimens back to London throughout the
journey
• He filled several warehouses with biological
specimens from this trip, for himself a
reputation as an extraordinary naturalist)
• The detailed study of his collections gave rise
to Darwin's’ On the Origin of Species
• Video link
Origin on the web
The Voyage
The Galapagos
• Ornithologist (John Gould)
sent Darwin a note arguing
that the mockingbirds of the
Galapagos were distinct
species.
• The finches and
mockingbirds appeared to
have “transmuted” from
species living on the
mainland of South America,
not far from the Galapagos
Direction of
evolution by
natural
selection
Was Evolution “new”?
• How did his thoughts vary from that of
Jean-Baptiste Lamark?
• Inheritance of
acquired characters
Lamarck on
Evolution
• Animals pass physiological
changes on to their offspring
• As the longer-legged birds
waded deeper, it would be the
habit of spreading the toes in
order not to sink into the
offshore mud, stretching the
skin in-between, that would
eventually give rise to webbed
feet.
– Reference link
Conversely, the disuse of an organ would cause it to wither and
disappear, which explained how snakes lost their legs
Darwin the intellectual
• Charles Lyell: Principles of
Geology
– use the cumulative effects of well
known processes rather than the
invocation of catastrophes and
miracles
• Malthus: On the principle of
population (1798); supplied a
semi quantitative ecological
modal
– reference
An “imperfect” Fossil record: One
should predict and describe general
features of the record in relation to
evolution
The missing
link
• How are
attributes
transmitted
from one
generation to
the next?
Darwin's problem • Where was Mendel when you needed
him?
• In an obscure monastery, with little
exposure for his findings
What is the Scientific Method in a
Darwin world?
If you are a naturalist, working with
preserved specimens. How do you do
experiments?
A study of the literature on breeding plants
and animals permitted the study of
massive amounts of “experimental” data
Modern Ecology
• In the early part of the 20th
century, ecology was largely
a descriptive science
• Lotka and Volterra became
interested in ecology.
These theoretical
mathematicians
– The preditor prey
mathematical relationship
model was developed
independently by Lotka, and
by Voterrra – hense the name.
• Did you know regressions
originated in modern
ecology?
Gause work in competition
Competitive exclusion & the start of
experimental ecology
• Gause studied population
shifts in fruit flies and
protozoan's.
• Natural selection is more
than just predator
pressure
Much more to come in
chapter 12
•
Gause work in competition
Density Dependent and density
independent regulation
Abiotic factors –
temperature and
rainfall were used to
predict numbers of
thrips
Competitive
interactions were not
very iportant in
population regulation
All about Thrips
From philosophy to science
• The move toward materialism:
– observations are to be explained in relations
to observable process – not spiritual forces
• In geology, this was the move away from
“catastrophists, and toward gradualists.
• Darwin extended the geologists “gradualist
beliefs to the realm of biology
Natural selection provides the “direction”
What is the directional force?
Evolution is “messy”
1. Natural selection is
neither efficient or
swift.
2. It is inconsistent and
unfocused, and only
over a very long
period do we see
sustained change in a
species
• The appendix in humans can cause death
when it ruptures
• Air-breathing aquatic mammals .
Biology and Geology are not separate
Central Concept : All live is related
Tree of life project
Horse
evolution
• Far from the idea of an
unchanging world; Darwin
proposed a world where
change is inevitable, and
constant.
• Horse evolution
Thoughts to ponder
6. What views did Darwin share with the
geologist Charles Lyell?
9 How did Darwin explain the evolution of
complex structures like the vertebrate
eye?
10 Why were materialism and gradualism
important to the development of
Darwin’s theory of evolution by natural
selection?