Chapter 18, Problem 1AQ

Explain why the process of endosymbiosis can be viewed as both an ancient event and a more recent event. What advantages could endosymbiosis give to both the endosymbiont and the host?

Summary Introduction

To explain:

The ancient and recent views of endosymbiosis process and its advantages to both the endosymbiont and the host.

Concept introduction:

Endosymbiosis is a process in which two types of organisms co-exist symbiotically. Both the partners get mutual benefit from each other. Endosymbiosis hypothesis explains about the origin of mitochondria and chloroplast and also explains the evolution of eukaryotic cell from prokaryotes.

Explanation of Solution

Process of endosymbiosis can be viewed as an ancient and recent event. The origin and evolution of organelles like mitochondria and chloroplast account for the ancient view of endosymbiosis process. The process of primary endosymbiosis is responsible for development of chloroplast and mitochondria during the early time of eukaryotic evolution.

Recent scientific studies have also shown that many organisms like protists (nonphototrophic) engulf other protists which are phototrophic in nature. These engulfed photosynthetic protists carry out the process of photosynthesis in nonphototrophic members for a long time period. These studies account for recent view of endosymbiosis and show that endosymbiosis is an ongoing and recent event. Hence, endosymbiosis is a process which can be viewed as both an ancient and an advance recent event.

In the process of endosymbiosis, both partners get benefits from each other. This process is advantageous to both endosymbiont and host because nonphototrophic host acquire the ability to produce organic food after its association with phototrophic endosymbiont. In turn, phototrophic endosymbiont is benefitted by acquiring extra protection from the host. Hence, endosymbiosis is a process which is advantageous for both the partners.