Biol 11
Ch 13 Notes
Evolution: Evidence of Change
Evolution: The process by which
have descended from
.
First published his
book “
by Means
of Natural Selection” in 1859. In this book, he
explained that if you look back far enough in
time, you would see that all species common
. He called this the principle of
Common
.
He also explained that because of the
that naturally occurs
within species, some individuals will have more
to survive than others. Those
individuals will have a better chance of
, and passing on the advantageous
.
He called this process
1
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Evidence that Evolution has Occurred:
1. Evidence in
a.
: Geologists have discovered
fossils of organisms that no longer
,
but have very similar
to
present-day species. Many of these fossils could
be compared and placed in a plausible
of change from
organism to the
present day. This isn’t proof, but it is a piece of
____________________.
Fossils are formed along with
rock. Sometimes, parts of organism’s bodies are
___________________. Other times, rock forms
around the
parts of the dead
organisms, (the
)
and it creates a bit of a
. The
__________________ material from the bodies
will eventually be
by
harder, longer lasting
compounds inside those “molds”. They call this
process
. Fossilization is
a tricky process, requiring
, and so the fossil record has
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to be put together like a
has many broken and lost pieces!
3
that
b. Sedimentary Rocks and Geology
Using the
geologists can find the
date of fossils. The law states that the
layers of ____________________ rock are
than the upper layers. Fossils
found in the layers of rock are the same
as the rock itself.
Through
geologists are able to tell the
age of some preserved bones that have been
uncovered, or determine the absolute age of
some of the
that are found
in the
rocks surrounding
the fossils.
Using
,
geologist have calculated that the Earth is about
years old.
The fossil record shows us that change happened
first on the
, and then change in
the organisms
.
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2. Evidence in Comparative Embryology
When you compare
of several
species in an
of
their development, they are very
in
. Later, the
look vastly
.
Why?
The theory of
explains
these different animals had a
that passed down the
sequence of developmental
. As the
animals evolved, they added steps to the
developmental sequence.
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3. Evidence in Comparative Anatomy
Many species have
structures – body parts that have very similar
__________________ structure but they have
different
. Examples
include: human arm and
human arm and
There are also many
structures – body parts present that are similar to
those of other organisms, but are
.
Examples include:
**do not confuse HOMOLOGOUS structures
with
structures –
structures have a similar
___________________ but have very different
________________ structure.
Examples: Bird wing and
Whale fin and
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4. Evidence in Comparative Biochemistry
Almost all living organisms use the same basic
biochemical
,
including
___________,
and many
enzymes. In fact, molecules such as
have been used to
determine how distantly related some
species are. The
the number
of differences in the molecule, the more
related the organisms are.
Biochemistry-Protein
Sequences
Living organisms use the same 20 amino acids to make their proteins. In addition, all life
uses the same DNA triplet codes. All life uses ATP as its usable form of energy. This
supports the idea that all life has descended from a common ancestor. During the long
history of life on earth, the protein sequences of various molecules have slowly changed.
Organisms that are very closely related will have few or no changes in their protein
sequences.
The protein that makes up cytochrome C in the mitochondria is composed of over 100
amino acids. Some of the amino acids in this protein change over long periods of time.
We find that comparing these sequences in living organisms today will reveal
evolutionary relationships. For example, two living species who shared a common
ancestor 500 million years ago will have more differences in their amino acids sequences
than two species who shared a common ancestor 10 million years ago.
Use the table below to answer the following:
1. Which organism below is the most distantly related to humans?
2. Which organism below is the most closely related to humans?
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3. Which evolved first, a tuna fish or a turkey?
4. Give evidence to support your answer to question 3.
Organism
Number of Differences in Amino Acids for Cytochrome C
Compared to Humans
Yeast
56
Tuna Fish 21
Turtle
19
Turkey
13
Rabbit
9
Monkey
1
Chimpanzee 0
Biochemistry-DNA
DNA comparisons show the same evolutionary pattern as protein
sequences, the fossil record, comparative anatomy and embryology.
Use the table below to answer the following:
1. Which organism below is most closely related to humans?
2. Which organism below is most distantly related to humans?
Organism
DNA Differences Compared to Humans
Chimpanzee
Gorilla
Orangutan
Gibbon
Old World Monkey
New World Monkey
Lemur
1.8%
2.3%
3.7%
5.1%
9%
15.8%
42%
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Mutation and Selective Breeding:
Belgian Blue cattle are a heavily-bred breed, producing
extraordinary amounts of meat. The sculpted, heavily
muscled appearance is known as "doubled muscled", and
is a trait shared by the Piedmontese breed. Critics
call Belgian blues "monster cows" and some countries
have advocated eliminating the strain [1]. They are
often unable to give birth without caesarean section.
Belgian blue has a natural mutation of the gene that
codes for myostatin, a protein that counteracts muscle
growth. The truncated myostatin is unable to function
in this capacity. This mutation also interferes with
fat deposition, resulting in very lean meat.
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