How can endosymbiosis complicate our attempts to reconstruct the evolutionary history of the eukaryotes?

Expert Answers

An illustration of the letter 'A' in a speech bubbles

Endosymbiosis is a condition of existence where one organism literally lives within another organism.  This condition has been used to explain the existence and production of lots of structures, from mitochondria and chloroplasts to flagella and cilia.  When trying to trace the evolutionary history of a specific eukaryotic cell, the existence of two cells, one living inside the other, can create some gray area of indecision.  How did this come to be?  Did on cell ingest the other and simply fail to digest it?  Or was it a simple fusion, a merger between two different types of cells?  Instead of answering the initial question of where the cell came from, we create new questions with the presence of the anomaly.  Evolution itself is dependent upon tracing the lineage of eukaryotic cells as they add or delete traits in a slow, gradual progression.  Endosymbiosis interrupts this slow progression by quickly interjecting something structurally that should not be there.

Approved by eNotes Editorial Team