Transcript Evidences of Evolution PPT

Evidences of
Evolution
 EQ:
Which evidence of evolution
is considered the strongest
evidence and why?
EVOLUTION IS
Genetic change in a
population over time.
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.
5 Evidences of Evolution
Today most evidences for
evolution are grouped into five
main categories:
 Fossil
Record
 Biochemical
 Comparative Anatomy
 Biogeography
1 - FOSSIL RECORD
 Paleontology
– study of fossils
Examples of fossils:
 Remains: bone, tooth,
or shell
 Traces: burrow,
footprint, or imprint
1 - FOSSIL RECORD
 Most
fossils are found in layered
sedimentary rock
 Oldest
fossils are
on the lowest layer
The fossil record shows:
 Life on Earth has
changed
 Increased number of
life forms
2 - BIOCHEMICAL
“Universal” GENETIC CODE
All living organisms contain DNA.
 Comparing the DNA of two organisms
can tell you how related they are.
 One way of doing this is called amino
acid sequencing.

2 - BIOCHEMICAL

AMINO ACID SEQUENCING

Proteins are
made of amino
acids.
By comparing the
amino acid
sequence of a
protein found in
two organisms
you can
determine how
related they are.

45
27
67
1
Number of differences
from human hemoglobin
2 - BIOCHEMICAL
 Comparing
amino acid sequence
shows:
Amino
Acid of

Closeness
Sequencing
is
relationship
probably the
 A probable
STRONGEST
common
evidence
for
ancestor
relationships
among
Human hemoglobin
organisms.
has 146 amino acids
Amino Acid Difference in
Hemoglobin Compared
with Human
Species
Difference
Gorilla
1
Rhesus Monkey
8
Mouse
Chicken
Frog
Lamprey
27
45
67
125
2 - BIOCHEMICAL

CLADOGRAM: diagram that
shows the evolutionary
relationship among a
group of organisms.
B
A
Where
would the
What organism
common
belongs
at each
ancestor
be?
branch?
Common
ancestor
150
C
D
Species Difference
Gorilla
1
Monkey
8
Mouse
27
Chicken
45
Frog
67
Lamprey
125
E
F
G
10 0
20
30
50 40
100
Number of Amino Acid Differences
3 COMPARATIVE
ANATOMY
 HOMOLOGOUS
STRUCTURES
 Similar
structures with different
functions
 ex: limbs of vertebrates (turtle,
alligator, bird, mammal)
Turtle
Alligator
Bird
Mammal
3 COMPARATIVE
ANATOMY
 ANALAGOUS
STRUCTURES
Different structures with similar
function
ex: wings of an insect, wings of a
bird
3 COMPARATIVE ANATOMY
 VESTIGIAL
STRUCTURES
Nonfunctional organs
that are reduced in size
but can be seen in other
related organisms
 ex: human tailbone,
appendix, whale pelvis

3 COMPARATIVE ANATOMY
 EMBRYOLOGY
 Embryos
of different species
may appear similar early in
development
 ex:
vertebrate
development
4 - BIOGEOGRAPHY
 Similar
organisms can
be found in many
different places
 organisms living
widely apart (even on
different continents)
have similar
appearance and
characteristics
4 - BIOGEOGRAPHY
 Biogeography shows that
geographically separated
species may have descended
from a common ancestor
Common ancestor