Cambrian Explosion and Evolution

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What is the primary reason for the development of internal skeletons and shells in early marine animals?

To increase mobility and navigation in the marine environment

To support the development of complex body plans

As a response to predation and the need for defence (correct)

To facilitate the development of food webs

What is the term used to describe the spectacular increase in marine biodiversity during the Ordovician period?

The Ediacaran Radiation

The Darwin's Dilemma

The Great Ordovician Biodiversification Event (correct)

The Cambrian Explosion

Which of the following groups of organisms is thought to have split from all other animals around 780 million years ago?

Cnidaria

Sponges (correct)

Echinoderms

Chordates

What is the estimated percentage of marine invertebrate genera that went extinct at the end of the Ordovician period?

60% Signup and view all the answers

What is the primary cause of the mass extinctions at the end of the Ordovician period?

The formation of massive glaciers and sea-level drop Signup and view all the answers

Which of the following groups of organisms is characterized by the presence of internal skeletons and shells?

Sponges, Echinoderms, and squids Signup and view all the answers

What is the term used to describe the phenomenon where the fossil record does not represent the origins of animal groups?

Darwin's Dilemma Signup and view all the answers

What is the estimated time period when the crown Cnidaria is thought to have emerged?

680 million years ago Signup and view all the answers

During which geological period did the Earth system undergo significant changes, leading to the diversification of marine taxa?

Cambrian Signup and view all the answers

What is the primary driver of the development of complex body plans in early marine animals?

Predation pressure and the need for defence Signup and view all the answers

What is the term used to describe the phenomenon where the fossil record does not fully capture the origins of animal groups?

Darwin's dilemma Signup and view all the answers

Which of the following events is thought to have triggered the mass extinctions at the end of the Ordovician period?

Glaciation and sea level changes Signup and view all the answers

What is the estimated time period when the sponges are thought to have diverged from all other animals?

780 million years ago Signup and view all the answers

During which geological period did the greatest diversification of marine invertebrates occur?

Ordovician Signup and view all the answers

What is the estimated percentage of all families that went extinct at the end of the Ordovician period?

25% Signup and view all the answers

Which of the following groups of organisms is characterized by the presence of internal skeletons and shells, and includes Echinoderms and squids?

Echinoderms and squids Signup and view all the answers

Cambrian Explosion and Evolution

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