Study the graph below which shows the major extinction events and answer the questions that follow.

Question

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Here are the answers to the questions based on the provided graph:

QUESTION 3

3.3.1 When did the Cenozoic era begin?
The Cenozoic era began approximately $\boxed{\text{65 million years ago}}$ .

3.3.2 Which mass extinction took place towards the end of the Palaeozoic era?
The mass extinction that took place towards the end of the Palaeozoic era was the $\boxed{\text{Permian extinction}}$ .

3.3.3 Approximately how many families of species died out at the end of the Palaeozoic era? Show ALL working.

Identify the number of families before the Permian extinction (end of Palaeozoic era).
Before the Permian extinction (around 250 million years ago), the number of families was approximately 400.
Identify the number of families at the lowest point after the Permian extinction.
After the Permian extinction, the number of families dropped to approximately 100.
Calculate the difference.
$\text{Families died out} = \text{Families before extinction} - \text{Families after extinction}$ $\text{Families died out} = 400 - 100$ $\text{Families died out} = 300$
Approximately $\boxed{\text{300 families}}$ of species died out at the end of the Palaeozoic era.

3.3.4 Explain why the number of families of organisms rapidly increased after each mass extinction.
After each mass extinction, there are many vacant ecological niches and a significant reduction in competition for resources. This allows the surviving species to undergo adaptive radiation, rapidly diversifying and evolving into new forms to fill these available niches, leading to a quick increase in the number of families.

Study the graph below which shows the major extinction events and answer the questions that follow.

Step-by-step solution

QUESTION 3

Identify the number of families before the Permian extinction (end of Palaeozoic era).

Identify the number of families at the lowest point after the Permian extinction.

Calculate the difference.

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