Dear fellow eukaryotes,

You know that you are all vertebrates. But have you ever thought about your identity as a eukaryote? Not yet? Then let’s catch up here.

Living organisms are divided into two groups. The prokaryotes (bacteria) and the eukaryotes. All living organisms that are not bacteria are eukaryotes. The world is as simple as that. All multicellular organisms – including us – are eukaryotes, because there are no bacterial multicellular organisms. And the unicellular organisms? That’s where it gets interesting, because there are also many unicellular eukaryotes, such as the paramecium. What makes eukaryotes so different from bacteria?

Single-celled eukaryotes differ from bacteria like cruise ships differ from boats with outboard motors. Everything inside eukaryotes is much more complicated, more effective but also more vulnerable than in simple, robust bacteria.

Bacteria have a simple DNA ring for the genetic information. Eukaryotes need an extra cell nucleus with lots of chromosomes in it.

Eukaryotes have all kinds of high-tech devices inside them that are unthinkable in bacteria. Eukaryotic cells contain such wonderful-sounding things as an endoplasmic reticulum for protein synthesis, vesicle vesicles for storing and transporting substances and the Golgi apparatus for producing various substances.

Particularly noteworthy in eukaryotes are the mitochondria, the power plants of the cell. The structure of the mitochondria provided the key to understanding the development of eukaryotes.

Did eukaryotes evolve from bacteria? Yes, but in a very unusual way. Eukaryotes are not derived from one type of bacteria, but from several types of bacteria. How is that supposed to work?

Eukaryotes are the result of the fusion of two different bacteria. One bacterium absorbed another bacterium. Both bacteria lived in symbiosis until they eventually became inseparable and formed a new living organism. Eukaryotes are therefore UNITED SPECIES.

A special group of eukaryotes, the plants, then took up another type of bacteria, which became the green chloroplasts in them.

In the chapter: „On genes and sex – the origin of the sexes“, it is described how the mitochondria were involved in the formation of „female“ and „male“.