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Activity 38

The document discusses mass extinctions, highlighting that over 90% of all organisms have become extinct since life began on Earth. It explains that extinction can occur naturally due to environmental changes and mentions hypotheses for past mass extinctions, such as meteorite impacts and volcanism. The activity includes questions for students to explore these concepts further.

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Zamokuhle Ngwenyeni
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71 views2 pages

Activity 38

The document discusses mass extinctions, highlighting that over 90% of all organisms have become extinct since life began on Earth. It explains that extinction can occur naturally due to environmental changes and mentions hypotheses for past mass extinctions, such as meteorite impacts and volcanism. The activity includes questions for students to explore these concepts further.

Uploaded by

Zamokuhle Ngwenyeni
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Grade

10
Life Science Activity 38

Topic Hypotheses for extinction DATE

1. Study the data and answer the questions

Mass extinctions occur when a large number of species die out. More than 90
percent of all organisms that have ever lived on Earth are extinct. When the last
animal of a species dies, the species becomes extinct. Since life began on Earth, the
normal rate of extinction has ben about two to five families of invertebrates and
vertebrates every million years. Extinction can be a natural process – small changes
in climate and habitat will result in a species being less suited to the new
environmental conditions and the species will die out. Mass extinction is when large
number of plant and animal species, over a large area, die out at the same time.
Various hypotheses have been proposed for the extinction, 65 million years ago,
such as the meteorite impact theory and volcanism theory.
Study the given data and answer the questions that follow:
1.1. In which Era of time did the biggest extinction occurred? (1)

1.2. There are different theories regarding mass extinction. One of these (6)
theories involves the collision of the earth with a meteorite. Explain why
this event may have caused mass extinction on earth.

1.3. Name one other theory that may have caused mass extinctions on earth. (1)

1.4 Discuss this theory named in 1.3 (9)

(17)

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