Q28.1-2CC - Campbell Biology

Question

Summarize the role of endosymbiosis in eukaryotic evolution.

Step-by-Step Solution

Answer

The term endosymbiosis indicates the process in which symbiotic organisms live inside the body of a host for a symbiotic relationship. It plays an important role in eukaryotic evolution. 

Evidence shows that algae evolved from a cyanobacterium. When heterotrophic eukaryotes engulfed cyanobacterium, red and green algae appeared. 

Some other protists, such as Euglenoids, and Chlorarachniophytes also formed by secondary endosymbiosis. These are formed when red and green algae are engulfed by other eukaryotes. 

Step 1: Meaning of evolution

The term evolution indicates the process by which changes appear in an organism after many generations. It takes millions of years to occur. It allows organisms to survive in nature better than their ancestors. 

Step 2: Endosymbiosis

Endosymbiosis is a type of symbiosis in which an organism such as cyanobacterium lives inside the host body, such as eukaryotic cells, to give a survival advantage to each other. 

It is of two types: primary endosymbiosis (when eukaryotic cells engulf prokaryotic cells) and secondary endosymbiosis (when a eukaryotic cell engulf another eukaryotic cell). 

Step 3: Functions of endosymbiosis in eukaryotic evolution

Endosymbiosis helps in the process of evolution. For example, when the host cell takes up the organelle mitochondria, the energy formed in the host cell increases, which helps the particular eukaryotic cell to survive faster than neighbor cells.