Download More Than An EyeWitness

More Than An EyeWitness
Evidence for Evolution
Sources of Evidence
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From the fossil record
From studies of anatomy
From studies of embryology
From studies of DNA/biochemistry
From observation
Transitional Organisms
• If evolution has
occurred in the past
there should be
evidence of
transitional organisms
in the fossil record.
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.
Identify how each organism uses
its forelimb
Frog
Lizard Bat
Human Cow
Whale bird
balance
Walking
Multiple
uses
swimming
flying
walking
flying
Anatomical Studies show
• Homologous parts –
similar in structure but
not necessarily
function – evidence of
evolution from
common ancestor
Anatomical studies show...
• Name two other
organisms that have
the ability to fly but
have wings very
different than those of
the bird or the bat?
Analogous structures
• Butterflies or insects have
wings but they are very
different from the birds.
These organisms do not
have a common ancestor
but have adapted to a
similar environment.
Again evolution explains
the similarities.
Anatomical studies show
• Vestigial parts – why
does a whale have a
pelvis and femur
bones if it has no hind
limbs?
Vestigial structures
• Why does this
salamander have eyes
if it never sees the
light of day?
Vestigial structures
Human vestigial structures
Ear muscles
Wisdom teeth
Appendix
Why do these structures occur?
• May be homologous to useful structures in
other organisms and thus suggest evolution
from an ancestor in which they do have a
use.
Modification of anatomy
• The stinger of the
wasp is not an entirely
different structure but
a modified ovipositor.
Anatomical Studies
• Anatomical studies of
cells show a
commonality in
structure of the cell
membrane among
almost all living
things. Does this
suggest a common
ancestor for all life?
Embryology Studies
• Even though it may
not be apparent at
this stage these
three organisms are
very different when
born. Why do they
look so similar
now?
Embryology Studies
• The organisms are:
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Fish
Bird
Human
Why would these
three, so different
looking organisms
at birth, look so
similar before birth?
Studies of Biochemistry/DNA
Species
Sequence of Amino Acids
in the Same part of the
Hemoglobin Molecule
Human
Lys-Glu-His-Iso
Horse
Arg-Lys-His-Lys
Gorilla
Lys-Glu-His-Lys
Chimpanzee
Lys—Glu-His-Iso
Zebra
Arg-Lys-His-Arg
Which organisms appear to be
more closely related to each
other?
Human and chimpanzee have no
differences in their amino acid sequence
suggesting their close evolutionary
relationship, they have a more recent
common ancestor. Their DNA would be
similar because DNA determines the
sequence of amino acids in proteins.
Observations of Evolution in
modern organisms
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Mosquitoes resistance to insecticides
Bacteria resistance to antibiotics
New strains of influenza viruses (?)
New strains of malaria causing Plasmodium
New strains of TB (tuberculosis)
Peppered moth
Darwin finches
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.)