Lesson 3: The Cambrian Explosion

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?

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

The cambrian explosion

PHANEROZOIC EON

Trilobite

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.

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.

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

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

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.

Pangea

Homework