Transcript EVOLUTION (part 2)

EVOLUTION
(part 2)
CHAPTER 13 read 286-298
The Evidence of Evolution
Hutton observed Hadrian’s wall
 Built between Scotland and England in
122-127 A.D.
 Still standing with little evidence of
erosion.
 Observed extinct volcano on which
Edinburough castle was built.
 Add drawing to notes
 Hyperlink to Unitedstreaming Hadrian’s
Wall
WONDERED?
 "How could a volcano erode in
6,000 years when a wall seems
not to have changed in 1,500
years?”
 Estimated the Earth's age to be
in the millions of years
"Theory of the Earth"
published by Hutton
 "The surface of the earth appears as it
does because of gradual geologic
changes caused by natural processes"
 ex. volcanoes, earthquake, erosion,
deposition, glaciers, hurricanes
Charles Lyell- furthered these ideas in
“Principles of Geology”
Uniformitarianism _________"theory of uniformity"
geological processes of the past
and present are the same and
are the only processes that
influence the way we see the
world today.
Catastrophism
 ____________ substantial
environmental calamities have
occurred that have changed the
face of the earth. Extinction was
followed by repopulation
V. DARWIN and Natural
Selection
 (1809-1882) Feb 12 same birthday as
Lincoln
 Studied medicine ministry poor student
 5 yr. round the world trip as the ship's
Naturalist
 H.M.S. Beagle 1831- 1836
 married his cousin Emma Wedgewood
 very seasick weak the rest of his life
 collected specimens, fossils, journal and
read captain's dinner guest
 his grandfather Erasmus Darwin was
interested in evolution
 A KEEN EYE FOR OBSERVATION
WAS Darwin’s GREATEST ASSET
B. What Darwin knew......
 1. The earth was old and it had
changed, read Hutton and Lyell
 2. organisms lived in very special
environments
 3. saw anatomical relationships
 4. selective breeding , pigeons,
dogs, horses, crops traits could be
passed on
 5. animals always over populate b/c
he read economist Thomas Malthus
The Galapagos Islands were
of special interest to him
because of their unique life
forms found no where else
 huge turtles,
many finches,
swimming lizards
QUESTION
 Why were the animals on the islands
slightly different than the animals on
the mainland?
 If an animal migrated to the island from
the continent, what caused it to
change (evolve)?
ANSWER
 Different environmental pressures
benefited or hurt the animals with
particular features
 (adaptations= an inherited feature
that increases an organism's chance
of surviving in an particular
environment).
2 fundamental factors that
determine evolutionary
change:
 ANCESTRY
 and
 ENVIRONMENT
DARWIN'S EXPLANATION
 "Natural Selection" is the mechanism
that allows some forms to survive and
others to die out.
 not a conscious force, as there is a
struggle for resources some
organisms die while others live to
reproduce.
 1859 “On the Origin of species by
means of Natural Selection”
 sold out the first day
Evolution for DUMMIES




1. over population
2. constant struggle for resources
3. variation in the species
4. the best adapted to the environment
survive
 5. surviving organisms transmit
variation to offspring
 ALFRED RUSSEL
WALLACE (18231913) Malay
Archipelago had
the same idea as
Darwin in 1858
(equally credited
but Darwin gave
extensive evidence)
 The Darwin–
Wallace Medal was
issued by the
Linnean society on
the 50th anniversary
of the reading of
Darwin and
Wallace's papers on
natural selection.
 The HARDWARE or material of
evolution is variation, mutation and
overpopulation
 The MECHANISM for evolution is
Natural Selection
 Theories also have a predictive
component as shown in the slides at
the after the homework answer keys.
Test Topics: Friday
 Evolution vs. Creationism
 Literal vs Figurative Language (interpretation of
the Bible)
 Darwin – voyage, life, ideas, book, natural
selection
 Labs – peppered moths, fossil lab (evidence vs.
inference)
 Text 275-282, worksheet
 Bishop Usher, James Hutton, intro to evolution
Evidence of relatedness
 Example: Transitional forms in the fossil
record
Hypothesis: If terrestrial vertebrates (tetrapods)
evolved from lobe-finned fish (sarcopterygians), then
there should be transitional forms that possess traits
that are intermediate.
Previously identified
transitional forms
From Ahlberg and Clack, Nature 2006
General Methods
 Scientists looked
specifically for the
transitional form of
interest by sampling…
From
Daeschler
et al., 2006
 Appropriate habitats
(stream system)
 Appropriate geologic time
(early Late Devonian =
385-376mya)
http://tiktaalik.uchicago.edu/photos.html
They found
Tiktaalik
roseae!
http://tiktaalik.uchicago.edu/photos.html
From Ahlberg and Clack, Nature 2006
From Daeschler et al., Nature 2006
http://tiktaalik.uchicago.edu/photos.html
From Shubin et al.,
Nature 2006
Summary
 The study of and the evidence for
evolution clearly fits within the scientific
framework.
 We use current evolutionary theory to
make and test hypotheses
 There are many thousands of examples
of evidence for evolution
What data from whole
genome sequencing can tell
us about evolution of humans
Example: the
Evolutionary Hypothesis
of Common Ancestry
Chromosome Numbers in
the great apes:
human (Homo)
chimpanzee (Pan)
gorilla (Gorilla)
orangutan (Pogo)
46
48
48
48
Testable prediction:
If these organisms share a common
ancestor, that ancestor had either
48 chromosomes (24 pairs) or
46 (23 pairs).
Ancestral
Chromosomes
Chromosome Numbers in
the great apes
(Hominidae):
human (Homo)
chimpanzee (Pan)
gorilla (Gorilla)
orangutan (Pogo)
Fusion
Homo sapiens
Inactivated
centromere
46
48
48
48
Telomere
sequences
Centromere
Telomere
Testable prediction:
Common ancestor had 48 chromosomes (24 pairs) and
humans carry a fused chromosome; or ancestor had 23
pairs, and apes carry a split chromosome.
Human Chromosome #2 shows the exact
point at which this fusion took place
Homo sapiens
Inactivated
centromere
Telomere
sequences
Chr 2
“Chromosome 2 is unique to the human lineage of
evolution, having emerged as a result of head-tohead fusion of two acrocentric chromosomes that
remained separate in other primates. The precise
fusion site has been located in 2q13–2q14.1 (ref.
2; hg 16:114455823 – 114455838), where our
analysis confirmed the presence of multiple
subtelomeric duplications to chromosomes 1, 5, 8,
9, 10, 12, 19, 21 and 22 (Fig. 3; Supplementary
Fig. 3a, region A). During the formation of human
chromosome 2, one of the two centromeres
became inactivated (2q21, which corresponds to
the centromere from chimp chromosome 13) and
the centromeric structure quickly deterioriated
(42).”
Hillier et al (2005) “Generation and Annotation of the DNA
sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731.