Human sperm cells with flagella (under a microscope): Eukaryote flagella Not the old kind of flagella About two billion years ago, the first eukaryote cells evolved from the earlier prokaryote [...]
Bacterium with a flagellum (under a microscope) Cells drift in the current... The simplest cells, developing about four billion years ago, had no way to control their own movement. They [...]
Euglena have red eyespots (thanks to Sharon Mooney) When did cells learn to see? About two billion years ago, or maybe a little later, some eukaryote cells developed the ability [...]
