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

2. Genetic change in a population through time.
EVOLUTION IS
Genetic change in a population through 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. Evidences of Evolution
Today most evidences for evolution are grouped into five main categories:
Biochemical
Fossil Record
Comparative Anatomy
Biogeography
Observable Events
Artificial selection

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
Photos by cbray

6. 1 - FOSSIL RECORD Most fossils are found in layered sedimentary rock
Oldest fossils are in the deeper layers
Life on Earth has changed
Increased number of life forms
Layers diagram by cbray

7. Fossil Record
The fossil record is the history of life recorded by remains from the past. Most fossils are at least 10,000 years old.
Body Fossils
Trace Fossils

8. 2 - BIOCHEMICAL THE GENETIC CODE
Triplets of DNA nitrogen-base sequences that code for specific amino acids
The sequences of bases that code for amino acids are the same in almost all organisms.
Genetic code table by cbray

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. Number of differences from human hemoglobin
2 - BIOCHEMICAL
AMINO ACID SEQUENCING
The amino acid sequence in a particular protein is compared between organisms. 8
125 45 27
Amino acid differences designed by cbray (with PPT clip art) 67 1
Number of differences from human hemoglobin

12. Amino Acid Difference in Hemoglobin Compared with Human
2 - BIOCHEMICAL
Comparing amino acid sequence shows:
Closeness of relationship
A probable common ancestor
Amino Acid Sequencing is probably the STRONGEST evidence for relationships among organisms.
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

13. 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

14. 3 - COMPARATIVE ANATOMY HOMOLOGOUS STRUCTURES
structures with different mature forms but develop from the same embryonic tissue
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. Homology
Homology: a similarity between species that is the result from the inheritance of traits from a common ancestor
The features of every creature reflect history as well as adaptation
3 types of homologies
- structural
- developmental
- genetic

17. Homology vs. Analogy
Natural selection appears to have favored similar adaptations in unrelated organisms in similar environments--> these structures are analogous
Whereas homologous structures
share structural similarity, but not function, analogous structures share function but not structural similarity since they evolved independently

18. Genetic Homologies All living organisms share the same genetic code
Chromosome and gene similarities between
species match evolutionary similarities
This is true for both coding regions and
“junk DNA”

19. 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
an organism’s evolutionary past
a common ancestor with species that have similar structures that are still functioning
Whale pelvis diagram by cbray

20. Vestigial Structures in Humans
Tailbone
Wisdom Teeth
Appendix

21. 3 COMPARATIVE ANATOMY EMBRYOLOGY
Embryos of different species may appear similar in early stages of development
Embryo drawings by cbray
ex: vertebrate development

22. 3 COMPARATIVE ANATOMY Comparison of similarities in embryos can show:
Relationship to a common ancestor
Embryo drawings by cbray

23. 4 - BIOGEOGRAPHY GEOGRAPHIC DISTRIBUTION OF ORGANISMS
organisms living widely apart (even different continents) may be similar because they share a common ancestor
Beaver
Muskrat
Beaver and Muskrat
Coypu
Capybara
Coypu and Capybara
Shows common ancestor

24. 5 - OBSERVABLE EVENTS
Some changes in species have been observed and studied
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

25. 6. Artificial Selection
Process by which plants and animals used by humans in agriculture, horticulture, and companionship have been derived from wild organisms
Humans use the best or more useful traits provided by nature and pass on to future generations

26. 6. Artificial Selection

27. 6. Artificial Selection
Picture depicting how farmers have cultivated wild mustard and selected the desirable traits
Nature provides the variations and humans select those variations that they find most useful

28. Works Cited
“Geographic Distribution of Organisms” photo: Miller, Kenneth and Levine, Joseph. (2004). Biology. Prentice Hall.
McGraw-Hill