History of Life on Earth

Which of the fossils have been found in Namibia?

• Mammal-like reptiles

• Early mammals

• Soft-bodied animals

• Glassopteris leaves

A problem in the accuracy of radiocarbon dating is that:

• scientists are not sure that radioactive decay actually occurs

• the decay rate of minerals can change without warning

• the rocks that contain the fossils can't be dated

• the half-life of carbon-14 is relatively short, and most fossils are millions of years old

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

When did the Cenozoic era begin?

• Around 65 mya, after the last major extinction.

• 260 mya

• 100 mya

Which mass extinction took place towards the end of the Paleozoic era?

• dragons

• The Permian extinction.

• rhinos

Explain why the number of genera of organisms increased rapidly after each mass extinction. (give full answer)

• The number of genera increased rapidly after each extinction event, because many genera were wiped out completely during the extinction, so their niches were left open. These niches were rapidly taken over by other genera, who diversified and formed new genera by natural selection.

• because These niches were rapidly taken over by other genera, who diversified and formed new genera by natural selection.

What evidence do scientists use to show that dinosaurs once existed on Earth?

• True: Fossils that were formed when the dinosaurs died, also animals like sharks, birds and crocodiles, that are closely related to dinosaurs.

• false: Fossils that were formed when the dinosaurs died, also animals like sharks, birds and crocodiles, that are not closely related to dinosaurs.

How long ago did the dinosaurs become extinct?

• a century ago

• 60 mya

• Dinosaurs became extinct 65 mya.

is this statement TRUE OR FALSE:

"The Earth was struck by an asteroid from outer space (at the Yucatan Peninsula off Mexico). This caused massive fires, earthquakes and tsunamis, as well as dust clouds that blocked the sun, so photosynthesis was severely reduced and global climate changed. Few animals survived, and these diversified to fill the vacant niches and multiplied to repopulate the earth. The mammals and flowering plants became the dominant life forms after the last mass extinction. "

• TRUE

• FALSE

HOW OLD IS THE EARTH WE LIVE IN?

• 4,6 billion years old

• 2000 YEARS OLD

• 5 BILLION YEARS OLD

what are Prokaryotes which have evolved, with photosynthesising bacteria called.

• cyanobacteria

• kynobacteria