1. Molecular Homologies
All living things have DNA. The more closely related two species are, the more similar their DNA sequences are.

2. Molecular Homologies Some proteins are common to many species.
Organism
Partial Amino Acid Sequence for Cytochrome C
Horse
Gly-Leu-Phe-Gly-Arg-Lys-Thu-Gly-Glu-Ala-Pro
Kangaroo
Gly-Ile-Phe-Gly-Arg-Lys-Thu-Gly-Glu-Ala-Pro
Human
Gly-Leu-Phe-Gly-Arg-Lys-Thr-Gly-Glu-Ala-Pro
Chicken
Gly-Leu-Phe-Gly-Arg-Lys-Thr-Gly-Glu-Ala-Glu
Tuna
Gly-Leu-Phe-Gly-Arg-Lys-Thr-Gly-Glu-Ala-Gly
Moth
Gly-Phe-Gly-Arg-His-Thr-Gly-Glu-Ala-Pro-Gly
Yeast
Gly-Ile-Phe-Gly-Arg-His-Ser-Gly-Glu-Ala-Pro
If 2 species are closely related, the DNA sequences that code for a common protein should be very similar.
If they are only distantly related, there should be more differences in the DNA sequence.
What similarities do you see?

3. % Difference of a Protein (Cytochrome C) Between Different Organisms
Molecular Homologies
% Difference of a Protein (Cytochrome C) Between Different Organisms
Who is the eel most like?
Carp
Who is the turtle most like?
Pigeon
Eel (Lamprey)
Organism
% Difference
Horse 15
Pigeon 18
Turtle
Carp 12
Carp (fish)
Organism
% Difference
Horse 13
Pigeon 14
Turtle
Lamprey 12
Pigeon (bird)
Organism
% Difference
Horse 11
Carp 14
Turtle 8
Lamprey 18
Horse (mammal)
Organism
% Difference
Pigeon 11
Turtle
Carp 13
Lamprey 15

4. Molecular Homologies Cyt-C Compared to Humans
Who is least like a human based on the differences in DNA?
A bacterium
What should a bacterium be most similar to?
Yeast
Cyt-C Compared to Humans
Organism
Cyt C % Diff
Rhesus Monkey 1
Rabbit 9
Horse 12
Tuna 20
Worm 25
Wheat 38
Yeast 41
Bacterium 65
Cyt-C Compared to a Bacterium
Organism
Cyt C % Diff
Horse 64
Pigeon
Tuna 65
Silkworm Moth
Wheat 66
Yeast 69
Does the data show this?
Not on this table
One explanation for this may be that bacteria are believed to be one of the earliest forms of life so everything else is very removed from it

5. Developmental Homologies
Cat
bat
dogfish
salmon
hellbender
chicken
possum
human
lamprey
gar
lungfish
snake
early
Inter-mediate
late
All vertebrates develop a similar body plan and look similar during early development.
Evolutionary scientists believe this similar development indicates a common ancestor for all vertebrates.