2/24 & 2/25- 7th Grade Agenda Learning Objective: Learn about other students’ Science Fair Projects Collect HW: Reading & Reading & Notetaking p. 143 -145 Science Fair Presentations Text Book Reading: 284 – 297 HW: Reading & Notetaking p. 146 - 148

Reflection Prompt: What is radioactive dating? How can it accurately tell scientist how old a piece of rock or fossil is?

Reflection Prompt: Write 5 facts that you learned during the Science Fair Presentations

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

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

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

What happened during Precambrian Time? Earth was formed about 4.6 billion years ago Earliest forms of life began about 3.5 billion years ago. They were single celled organism similar to bacteria About 2.5 billion years ago, organisms started to use the process of photosynthesis. This increased the amount of oxygen in the atmosphere.

Development of Atmosphere

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

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.

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

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

Permian Period (286 Million Years Ago)

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?

Mesozoic Era – Triassic, Jurassic Cretaceous Period (245 – 66 Million Years ago)

End of Cretaceous Period, there was another mass extinction (66 Million years ago) Where did the asteroid hit? Asteroid hit near southeastern Mexico (Yucatan Peninsula) When the asteroid hit Earth, the impart threw huge amount of dust and water vapor into the atmosphere

Which animal is the closest living relative of Dinosaurs? Birds are considered to be closest relatives of dinosaurs