AP BIOLOGY

Detailed explanation-1: -Eukaryotic cells may have evolved when multiple cells joined together into one. They began to live in what we call symbiotic relationships. The theory that explains how this could have happened is called endosymbiotic theory. An endosymbiont is one organism that lives inside of another one.

Detailed explanation-2: -According to the endosymbiotic theory, the first eukaryotic cells evolved from a symbiotic relationship between two or more prokaryotic cells. Smaller prokaryotic cells were engulfed by (or invaded) larger prokaryotic cells.

Detailed explanation-3: -Their evolution is explained by endosymbiotic theory. Mitochondria and chloroplasts evolved from prokaryotic organisms. Eukaryotic cells would go on to evolve into the diversity of eukaryotes we know today.

Detailed explanation-4: -The endosymbiosis theory states that eukaryotic cells evolved from free-living prokaryotic cells. Specifically, this theory states that eukaryotic cells evolved when prokaryotic cells were engulfed by other cells, and eventually developed a symbiotic relationship between them.