Chapter 21.17, Problem 1MC

Summary Introduction

To determine:

The approaches that are used by the researchers to draw the conclusion about the events that occurred hundreds of millions of year ago by investigating the DNA of living sponges.

Concept introduction:

Animals are likely to be originated in Precambrian times in the oceans. The major group of animals appeared after an eventful millions of year interval of the Cambrian period. The evolution process occurred so quickly during this period and results in the evolution of animals from sponges to early chordates.