1. 4/26 & 4/27- 7th Grade Agenda
Learning Objective: Learn to identify igneous, sedimentary & metamorphic rocks
Rock Cycle Lab
Text Book Reading: 282 – 284
HW: Reading & Reading & Notetaking p

2. Reflection
Prompt: Write descriptions of how igneous, metamorphic and sedimentary rocks should look like.

3. These rocks are some of the oldest fossils in the world
These rocks are some of the oldest fossils in the world. How old are they?
Stromatolites: Remains of ocean reefs created by bacteria more than 3 billion years ago.

4. What is Radioactive Decay?
Radioactive Decay: over time, unstable elements break down or decay by releasing particles and energy.

5. What is half-life?
The half-life of a radioactive element is the time it takes for half of the radioactive atoms to decay.

6. If Geologic time went by in a single day, when did humans first appear?
Humans first appear one second before midnight

7. Geological Time Scale Paleozoic: Paleo means ancient or early
Mesozoic: Meso means middle
Cenozoic: Ceno means recent

8. When was the earth created?
Earth was formed about 4.6 billion years ago

9. When did life began on earth?
Earliest forms of life began about 3.5 billion years ago. They were single celled organism similar to bacteria

10. Development of Atmosphere

11. What happened during Paleozoic Era 544 – 245 Million Years ago?
Cambrian Explosion: At the beginning of the Paleozoic Era, a great number of different kinds of organisms evolved.

12. Cambrian Period – Explosion of Life in the sea (544 Million Years ago)

13. Devonian Period – Animals invade the land (408 Million Years Ago)

14. Permian Period (286 Million Years Ago)

15. End of the Permian Period, there was a mass extinction – (245 Million years ago)
95% of life in the oceans disappeared
What do you think might have cause the mass extinction?