evidencesofevolution-120207073412-phpapp02.pdf

Refer

1. EVIDENCES OF
EVOLUTION
Fossil Record
Biochemical
Comparative Anatomy
Observable Events

2. EVOLUTION IS
Genetic change in a
population through time.

3. Charles Darwin
On his journey around the world,
Darwin found evidence of
gradual change (evolution).
Darwin cited
evidences he
found in fossil
records,
geographic
distribution and
homologous
structures.

4. Evidences of
Evolution
Today most evidences for
evolution are grouped into
four main categories:
Biochemical
Fossil Record
Comparative Anatomy
Observable Events

5. 1 - FOSSIL RECORD
Paleontology – study of fossils
Fossil – remains or traces of an
organism that lived long ago
Remains: ex. bone,
tooth, or shell
Traces: ex. burrow,
footprint, or
imprint

6. 1 - FOSSIL RECORD
Most fossils are found in layered
sedimentary rock
Oldest fossils
are on the
lowest layer

7. 1 - FOSSIL RECORD
Comparing fossils from different
layers shows:
Life on Earth
has changed
Increased
number of
life forms

8. 2 - BIOCHEMICAL
THE GENETIC CODE
Triplets of DNA nitrogen-base
sequences that code for specific
amino acids
The amino
acid triplet
is the
same in
almost all
organisms.

9. 2 - BIOCHEMICAL
The similarity of triplet DNA
codes making-up amino acids
shows:
A probable
common
ancestor for
all life on
Earth

10. 2 - BIOCHEMICAL
“Universal” GENETIC CODE
Similar genes
Over the ages, the genetic code
has passed
unchanged (or
nearly so) from
parent to
offspring.

11. 2 - BIOCHEMICAL
AMINO ACID SEQUENCING
The amino acid
sequence in a
particular
protein is
compared
between
organisms. Number of differences from
human hemoglobin
45
167
8
27
1 2 5

12. 2 - BIOCHEMICAL
Comparing amino acid sequence
shows:
Closeness of
relationship
A probable
common
ancestor
Species Difference
Gorilla 1
Rhesus Monkey
8
Mouse 27
Chicken 45
Frog 67
Lamprey 125
Amino Acid Difference in
Hemoglobin Compared
with Human
Human hemoglobin
has 146 amino acids
Amino Acid
Sequencing is
probably the
STRONGEST
evidence for
relationships
among
organisms.

13. What organism
belongs at each
branch?
2 - BIOCHEMICAL
CLADOGRAM: diagram that
shows the evolutionary
relationship among a
group of organisms.
SpeciesDifference
Gorilla 1
Monkey 8
Mouse 27
Chicken 45
Frog 67
Lamprey 125
Amino Acid Difference
in Hemoglobin
Compared with Human
Number of Amino Acid Differences
150
100
50
0
40
20
30
10
G
F
E
DC
B
A
Common
ancestor
Where would the
common ancestor
be?

14. 3 COMPARATIVE ANATOMY
HOMOLOGOUS STRUCTURES
structures with similar structure
but different function
ex: limbs of vertebrates (turtle,
alligator, bird, mammal)
Turtle
Alligator
Bird
Mammal

15. 3 COMPARATIVE ANATOMY
Homologous structures show
Similar genes
Descent from a common ancestor
Turtle
Alligator
Bird
Mammal
Ancient lobe-finned fish

16. 3 COMPARATIVE ANATOMY
VESTIGIAL STRUCTURES
organs so reduced in
size that they are
nonfunctioning
remnants of similar
organs in other species
ex: human tailbone,
appendix, whale pelvis

17. 3 COMPARATIVE ANATOMY
Vestigial structures show:
an organism’s
evolutionary past
a common ancestor
with species that have
similar structures that
are still functioning

18. 3 COMPARATIVE ANATOMY
EMBRYOLOGY
Embryos of different species
may appear similar in early
stages of development
ex: vertebrate
development

19. 3 COMPARATIVE ANATOMY
Comparison of
similarities in
embryos can
show:
Relationship
to a common
ancestor

20. 4 - OBSERVABLE EVENTS
Some changes in species have
been observed and studied:
Peter & Rosemary
Grant’s Study of
Beak Size Shift in
Darwin’s Finches
H. Kettlewell’s Study
of Peppered Moth
Color Shifts

21. 4 - OBSERVABLE EVENTS
 Observable events show that
evolution is an ongoing process
Peter & Rosemary
Grant’s Study of
Beak Size Shift in
Darwin’s Finches
H. Kettlewell’s Study
of Peppered Moth
Color Shifts

22. Works Cited
“Geographic Distribution of Organisms” photo:
Miller, Kenneth and Levine, Joseph. (2004).
Biology. Prentice Hall.