1. ACTIVITY 100: DNA: THE EVIDENCE WITHIN CHALLENGE  HOW DOES DNA PROVIDE EVIDENCE ABOUT HOW ANIMALS ARE RELATED? VOCABULARY: DNA CLASSIFICATION

2. Classification: the process of grouping similar organisms based on similarities in form and structure, physiology, and genetic information. DNA: Deoxyribonucleic Acid  The genetic material, located inside the nucleus of cells, that contains the information for cell growth, cell division, and cell function.

3. GETTING STARTED  Read the Intro on Page F-51  Read the Scenario “The Common Thread” on Page F- 52  Copy the Chart into your Science Journal on F-52.

4. NUMBER OF DIFFERENCES BETWEEN DNA SEQUENCES Mammal # 1 (Dog) Mammal # 2 (Whale) Mammal # 3 (Horse) Reptile Fish Mammal # 1 X Mammal # 2 XX Mammal # 3 XXX

5. PART B Does every species within a class display every common characteristic for that class? Review Act. 76 “People. Bats and Birds”

6. NUMBER OF DIFFERENCES BETWEEN DNA SEQUENCES Fish Mammal # 1 Mammal # 2 Mammal # 3 Reptile Kiwi Platypus Armadillo Fruit Bat

7. ANALYSIS #1 DNA molecules contain the informational blue print for the organism, which is inherited through generations of evolution. Two species with very similar DNA sequences are more closely related than two species with less similar DNA Therefore, DNA comparisons provide a major line of evidence for how closely related any two species are!!

8. ANALYSIS #2 Because the seahorse is a fish, the DNA of a seahorse is much more likely to resemble that of a trout, which is also a fish, than that of a horse, which is a mammal. In this activity, we found sequences from different mammal species are much more similar to one another than they are to sequences from other species of fish, reptiles, or birds.

9. ANALYSIS #4 Although humans and lizards share a common ancestor, humans did not evolve from lizards. The commonly shared ancestor of both humans and lizards has been extinct for hundreds of millions of years. It was an early reptile, and it may have been lizard-like, but in the millions of years since it became extinct both the mammalian and reptilian lineages have undergone tremendous amounts of diversification. In fact, no mammalian species alive today, evolved from another mammalian species alive today, much less from a reptile species alive today!