Transcript More Than An EyeWitness

More Than An EyeWitness
Evidence for Evolution
1
Sources of Evidence
From studies of
embryology
Biochemistry
From observation
From the fossil record
From studies of
From studies of DNA
anatomy
2
From Geographic Distribution
Fossil Structure
3
3
Archeopteryx
• Archeopteryx shows
evidence of the
evolution of birds
from reptiles….there
is evidence of
feathers, a
characteristic of birds,
and claws, a
characteristic of
reptiles.
4
5
5
is called….
D
C
E
A
B
F
G
6
6
Homologous Structures
•
These organisms have body parts with anatomical similarities but
functional differences which suggests their evolution from a common
ancestor but the organisms have adapted to different environments. These
homologous parts – similar in structure but not necessarily function - are
evidence of evolution from a common ancestor; this can be seen in the fossil
record.
7
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
7
Anatomical studies show...
• What are other
organisms that have
the ability to fly but
have wings very
different than those of
the bird?
• Structures like the
wings of birds and
insects are called…..
8
Analogous structures
• Butterflies or insects have wings but they are very different from
the birds. These organisms do not have a recent common
ancestor but have evolved to have similar adaptations for a
similar environment. They show analogous structures: parts
similar in function but not anatomical structure. So again
evolution explains the similarities.
9
Copyright © The McGraw Hill Companies. Permission required for reproduction or display
9
Do these organisms, a bird, mammals and a fish, show
analogous structures or homologous structures?
•
Convergent evolution as seen in the penguin, sea lion,
shark and whale, results in analogous structures. If
you were to look at the bone structure of the front
fin/wing, you would find very different bone
structures. These organisms have adapted to similar
environments.
10
Do these organisms show analogous or homologous structures?
Many different species evolving from a recent common ancestor
would be an example of divergent evolution/adaptive
radiation, with the organisms showing homologous structures.
Over 70 lemur species evolved from a
species that colonized Madagascar less
than 60 million years ago.
11
Why would this “bird” have wings if it
doesn’t fly?
• Structures that are so reduced in size that
they are vestiges or traces of homologous
organs in other species are called vestigial
structures.
12
Anatomical studies show
• Vestigial parts – why does a whale have a pelvis and
femur bones if it has no hind limbs?
• Vestigial parts – why does a rubber boa have a
remnant hind limb (spur)?
13
Vestigial structures
• Why does this
salamander
have eyes if it
never sees the
light of day?
Mexican Tetra
fish (Astyanax
mexicanus)
14
Vestigial structures
Human vestigial structures
Ear muscles
Wisdom teeth
Appendix
15
15
Why do these structures occur?
• These structures may be homologous to
ones that had a function in the ancestors of
these organisms thus suggesting their
evolution from this common ancestor.
16
Embryology Studies
• Even though it may not be apparent during the first stage of
development, these five organisms are very different at later
stages of embryonic development and at birth. (1) Why do
they look so similar during early development? (2) What do
you think each organism is?
A
B
C
D
Copyright © The McGraw Hill Companies. Permission required for reproduction or display
E
17
Embryology Studies
• The organisms are:
–
–
–
–
–
Fish
Salamander
Chicken
Rabbit
Human
18
Organisms having
more similarities
during later stages
of development are
thought to have a
more recent
common ancestor.
Once again this
demonstrates
evidence that
evolution has
occurred.
19
Studies of Biochemistry
Species
Sequence of amino acids in the same part of the hemoglobin
protein for four different species
Human
V-H-T-A-T-A-A-S-D-L-A-T-D-K-R-C-H-E-Y-A
Chimp
V-H-T-A-T-A-A-S-D-L-A-T-D-K-R-C-H-E-Y-A
Gorilla
V-H-T-A-T-A-A-S-D-L-A-T-D-K-K-C-H-E-Y-A
Horse
V-Q-S-A-L-A-S-G-E-V-H-A-D-K-R-V-R-D-Y-A
20
Conclusion?
Humans and chimpanzees have
no differences in this amino acid
sequence suggesting their close
evolutionary relationship; they
have a more recent common ancestor than
any other two species shown.
21
Which organisms appear to be
more closely related to each
other?
Species
Percent of Amino Acids That Are
Identical to the Amino Acids in a
Human Hemoglobin Polypeptide
100%
Human
Rhesus monkey
95%
Mouse
87%
Chicken
69%
Frog
Lamprey
54%
14%
22
DNA
• The sequence of the
nucleotides making up
the DNA (DNA makes
up genes) would also
be similar because
DNA determines the
sequence of amino
acids in proteins.
23
Species
DNA sequence from a gene in the immune system
that recognizes diseases invading the body
Human
TTTCTTGGAGTACTCTACGTCTGAGTGTCATTTCTTC
Chimp
TTTCTTGGAGCAGGCTAAGTCTGAGTGTCATTTCTTC
Goat
TTTCCTGAGGTATTGTAAGAGAGAGTGTCATTTCTCC
Deer
TTTCTTGGAGTATCATAAGAGCGAGTGTCATTTCTTC
Duck
CTTCCATGAGATGCTGGCGTTTGAGTGTCACTACCTC
Chicken
CTTCCAGTGGACTTTTAAAGCAGAGTGCCACTACCTG
The underlined parts are those that are identical to the human
sequence.
24
DNA sequences are used to make “family trees” so that
we can see how closely related different species are.
Goat
Deer
Human
Chimpanzee
Duck
Chicken
25
What’s this
diagram
showing you?
What could be a
possible
explanation for
this?
26
Penicillin Patch
Penicillin patches were
placed in a bacteria
culture that had only
Streptococcus
pneumoniae (Bacteria
strain that causes
Pneumonia). One patch
showed growth of
bacterial colonies while
another one did not.
What happened?
Bacteria Colony Grows
27
27
Present
EVIDENCE
FROM
GEOGRAPHIC
DISTRIBUTION
How could marsupials have gotten from
their place of origin to locations half a
world away? (The distribution of living
things on the globe provides information
about the past histories of both living
things and the surface of the Earth )
Past
28
Summary of Evidence for Evolution
From studies of
embryology
Biochemistry
From observation
From the fossil record
From studies of
From studies of DNA
anatomy
29
From Geographic Distribution
Has and Does Evolution Occur?
• Scientists do not dispute that evolution does occur.
Evolution is a FACT.
• How evolution occurs is not completely understood.
• Charles Darwin explained how evolution occurred
through natural selection. Natural selection is a well
documented THEORY uniting all of biology.
• Modern evolutionary theory uses ideas of genetics,
particularly mutations, to help explain how evolution
may occur. (Darwin didn’t know about mutations.)
30
30