1. Lesson 3: The Cambrian Explosion

2. Essential questions
How were Phanerozoic life-forms different from earlier life-forms?
How did asteroid impacts affect Earth’s environment?
What natural processes change Earth’s surface?

3. Vocabulary Extinct Adaptation Phanerozoic eon Thermal Energy
Environmental changes
The Cambrian Explosion

4. The cambrian explosion

5. PHANEROZOIC EON

6. Trilobite

7. Phanerozoic Eon and The Cambrian Explosion
 It covers roughly 542 million years (until nowadays)
Phanerozoic = ¨Visible Life¨
Phanerozoic rocks contain fossils that are large enough to see without using any device
Abundant animal life has existed
Organisms developed hard parts such as shells
Shells and bones are more easily fossilized than soft bodies
The change in life on earth is known as Cambrian Explosion
Environmental changes means rapid evolution of new organisms.

8. Adaptation Extinction
Environmental changes means rapid evolution of new organisms, there are other that adapt to new conditions or die
Adaptation
Extinction
Characteristics that species develop over time that help them to survive in a particular environment
When species are unable to adapt to new environmental conditions and all the members die.

9. The impact of Asteroids
What kind of environment al changes can cause a mass extinction?
The impact of Asteroids

10. The Impact of Asteroids
Large impact throw crushed rock and dust into the athosphere blocking out sunlight
Without sunlight there is a global cooling and the climate changes
These changes are drastic and rapid
Don’t allow species to adapt to the new environment
Some species (marine, reptiles, flying reptiles…) became extinct

11. Earth’s Changing Surface
Evolving since it’s formation
Continents changed its position throughout the Phanerozoic eon
Thermal energy escaps from Earth’s interior, which mean that continents don’t stop moving
Volcanic activity
Mountain building
Changes continue
Volcanism, plate tectonic motion, weathering, and erosion continously change Earth surface.

12. Pangea

13. Homework