1. Evidences of Evolution
EQ: Which evidence of evolution is considered the strongest evidence and why?

2. Genetic change in a population over time.
EVOLUTION IS
Genetic change in a population over time.
Population Dynamics
POPULATIONS IN ECOSYSTEMS

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

5. 1 - FOSSIL RECORD Paleontology – study of fossils
Fossils come in many forms: bones, teeth, footprints, imprints
Most fossils are found in layered sedimentary rock
Oldest fossils are on the lowest layer
Photos by cbray

6. 1 - FOSSIL RECORD The fossil record shows: Life on Earth has changed
Increased number of life forms
Layers diagram by cbray

7. 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.

8. Number of differences from human hemoglobin
2 - BIOCHEMICAL
AMINO ACID SEQUENCING
Proteins are composed of amino acids.
By comparing the amino acid sequence of a protein found in two organisms you can determine how related they are. 8
125 45 27
Amino acid differences designed by cbray (with PPT clip art) 67 1
Number of differences from human hemoglobin

9. Amino Acid Difference in Hemoglobin Compared with Human
2 - BIOCHEMICAL
Comparing amino acid sequence shows:
Closeness of relationship
A probable common ancestor
Amino Acid Difference in Hemoglobin Compared with Human
Species
Difference
Gorilla 1
Rhesus Monkey 8
Mouse 27
Chicken 45
Frog 67
Lamprey
125
Amino acid differences chart by lpriddy
Human hemoglobin has 146 amino acids

10. Amino Acid Sequencing is probably the STRONGEST evidence for relationships among organisms.

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

12. 3 COMPARATIVE ANATOMY HOMOLOGOUS STRUCTURES
Similar structures with different functions
ex: limbs of vertebrates (turtle, alligator, bird, mammal)
Turtle
Alligator
Bird
Mammal

13. 3 COMPARATIVE ANATOMY ANALAGOUS STRUCTURES
Different structures with similar function
ex: wings of an insect, wings of a bird 13

14. 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
Whale pelvis diagram by cbray

15. 3 COMPARATIVE ANATOMY EMBRYOLOGY
Embryos of different species may appear similar early in development
Embryo drawings by cbray
ex: vertebrate development

17. 4 - BIOGEOGRAPHY
Similar organisms can be found in many different places
Organisms living widely apart (even on different continents) have similar appearance and characteristics.

18. 4 - BIOGEOGRAPHY
Biogeography shows that geographically separated species may have descended from a common ancestor
Common ancestor