1. 2/14 - 7th Grade Agenda Collect HW: Homologous Structures
Late Science Fair Procedure Data table & Graphs Presentations
Text Book Reading: 244 – 246
HW: Reading & Notetaking p. 123 – 124
Reminder: Science Fair Project Due 2/22 & 2/23 (50 Points)

2. Reflection
Prompt: Why is it better to describe evolution as a tree instead of a ladder?

3. Can evolution be described as a tree or a ladder?

4. Fossils in which minerals replace all or part of an organism is called…
Petrified Fossils

5. Most Common Fossils are Molds and Casts. What are they?
Mold: Hollow in shape and are formed when an organism buried in sediment dissolves
Cast: Copy of an organism’s shape formed when minerals seep into a mold
Dinosaur Foot Print

6. What is a carbon film fossil?
Carbon film is an extremely thin coating of carbon on rock.

7. What are Trace Fossils?
Trace Fossils provide evidence of the activities of ancient organisms. Such as Dinosaur foot prints
Megalosaurus footprint A meat eating predator from the Jurassic

8. What are some of the ways that extinct animals can be preserved with little or no change?
Amber
Freezing

9. The preserve remains or traces of an organism that lived in the past is called…
Fossil
Most fossils form when organism that die become buried in sediments
Remains of most animals never becomes fossil

10. How do fossils form?

11. Gradualism vs Punctuated Equilibria
Gradualism: The theory that evolution occurs slowly by steadily
Punctuated Equilibria:Evolution occurs during short periods of rapid change separated by long periods of little or no change

12. What are homologous structures?
Similar structures that related species have inherited from a common ancestor

13. Similarities in Early Development

14. Human Embryos have tails and gill slits

15. Similarities in DNA – Is an Elephant and this Shrew closely related?
Scientists can determine how closely related the species are by comparing the DNA of different species
DNA comparison has revealed that the tiny elephant shrew is closely related to the elephant

16. Branching Tree shows how closely related species are