Chapter 18, Problem 1Q

Summary Introduction

To explain: All present day cells have arisen by an uninterrupted series of cell divisions extending back in time to the first cell division. Strictly true or false.

Introduction: The origin of life is explained with several concepts. One such concept is that an ancestral cell gave rise to all types of organisms irrespective of prokaryotes and eukaryotes.

Answer to Problem 1Q

Correct answer: The given statement is true.

Explanation of Solution

Several evidences indicate that all organisms came from a common ancestor. It is unlikely that the first cell that was formed became the founder cell for all the cells that are living currently. Evolution is a highly indirect process with focused development. So, there is a higher chance that several unsuccessful trials occurred and the cells replicated simultaneously. The ones that adapted to environmental conditions and competition survived and the others perished. Therefore, it can be hypothesized that one ancestral cell got fortunate enough that it got relatively adapted to the environment and stabilized itself. It is known that all cells arise from pre-existing cells. The first cell division is the division of the cell that got fortunate enough to escape the selection pressure. The cells that came thereafter went on with uninterrupted division. Some may have perished, but some continue with the cell division process. Hence, the statement is true.