Download Chapter 10 Section 2

OTHER OBSERVATIONS
Chapter 22.3
Overwhelming Evidence
1.
2.
3.
4.
5.
Fossil Record
Biogeography
Direct Observation
Homology
Molecular Analysis
1. Fossils

Show evidence of the history of life on Earth and
links extinct to extant species
1. Fossils
1. Fossils
2. Biogeography

Closely related species are commonly found in same
geographic region
2. Biogeography

Closely related species explain continental drift
2. Biogeography

Distant regions of similar habitats contain similar
appearing organisms
3. Direct Observation

Male guppies have variable colors
 Colors
attract mates
 Colors attract predators

After many years of study:
with many predators produce drab ♂
 Ponds with few predators produce colorful ♂
 Ponds
3. Direct Observation

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Staphylococcus aureus
Streptococcus pyogenes
Enterococcus faecalis
Pseudomonas aeruginosa
Escherichia coli
Salmonella
Clostridium difficile, etc…
3. Direct Observation

Ensatina Salamanders
4. Homology

Compare body structures of different organisms to
determine evolutionary relationships.
4A. Homologous Structures
4B.Vestigial Structures

Vestigial Structures:
 Structures
with NO known functions
 Show remnants of evolutionary past
4B.Vestigial Structures

Homo sapiens
 Appendix:
previous stomach
 Coccyx: previous tail
 Wisdom teeth: previous herbivore
 Ear muscles: previous limited head mobility
 Plica semiluneris: previous nictitating eyelid
 Goosebumps: (hair standing up to scare off predators)
 Palmer grasp reflex: (infants grasp mother after birth)
4C. Developmental Structures

Embryonic development shows relationships
5. Molecular Analysis

We can also compare similarities in DNA & amino
acid sequences between organisms
5. Molecular Analysis


Humans and Chimpanzees have ~98% of the same
genes and therefore have a common ancestor
~7million years ago