KEY CONCEPT Multicellular life evolved in distinct phases.

​

​

​Lesson 5 Radiation of multicellular life

​

The first three eons were: Hadean, Archean, and Proterozoic. They are better known as Precambrian time.​

​

Read this chart carefully. What do you notice about the mass extinction and the borderline of the period?​

​

​1. When

2. Which group of organisms dominates the era? Age of ......​

3. Which group of organisms appears​ in the Era?

4.Extinction that marks the end of the Era​

​Paleo: old

Meso: middle

Ceno: new​

• 544 mya - 248 mya

• Cambrian explosion: huge diversity in marine animals such as sponges, corals, snails, trilobites, fish, and sharks.

• ​Multicellular organisms first appeared

• ​Life moved onto land in the middle of the Paleozoic era. Reptiles appeared

​

​Some text here about the topic of discussion.

​Paleozoic era

​

​

• When: The Permian Period of the Paleozoic Era (about 250 million years ago)

• Size of the Extinction: An estimated 96% of all living species eliminated

• Suspected Cause or Causes: Unknown—possibly asteroid strikes, volcanic activity, climate change, and microbes

​

​Mesozoic era​

• ​248 mya -65mya

• The Mesozoic era is known as the Age of Reptiles.

• ​Dinosaurs, birds, flowering plants, and first mammals appeared.

• At the end of Mesozoic era, nearly 75% of all living species is eliminated due to extreme asteroid or meteor impact

• ​65mya-

• "The age of mammals". Placental mammals and monotremes evolved and diversified.

• Modern humans appeared late in the era​

​

​Some text here about the topic of discussion.

Cenozoic era

​