Eukaryota

Keywords

Eukaryote, Eukaryota, multi-celled organism, nucleus, common ancestor, chimeric protobacterium.

Introduction

Eukaryota are multi-celled organisms. Anything that is a living organism that is more than one cell in size is considered a eukaryote. So this means that a plant is a eukaryote. A sheep is a eukaryote. A fish is a eukaryote. You are a eukaryote.

What's the Difference?

The eukaryote has a different makeup to the likes of bacteria and archaea, in the fact that each cell in the organism has a nucleus in them. So, your DNA has a nucleus which holds your genetic information. This is because you are a eukaryote. That being said, bacteria and archaea both hold DNA, but do it in a different way.

All eukaryotes carry a common ancestor. If you track far enough back in time - we're talking thousands of years ago - then you'll find that you all share a similar ancestor.

Interesting fact: the human genome shares 50% genetic information with a banana. It is mainly the proteins, rather than the DNA though.

How Eukaryotes Reproduce

Typically, a eukaryote can replicate the same as a bacteria or archaea does. But it is usually by a different process. For example, the cells in our body replicate by a process called mitosis. This is where there is a single that duplicates everything within it, and through a process called cytokinesis then splits in half with the organelles inside. Other processes include meiosis, which happens sometimes in eukaryotes, but only for a few specific cell types. This is mainly how bacteria reproduce, as it clones the cell.

Origin Story

No, this isn't like the origin story for Wolverine or anything like it, but eukaryotes do originate from a source of chimeric protobacterium. So in essence, although eukaryotes have multiple cells, and carry organelles within them, they were first bacterium.

The first known sign of eukaryotic organisms happened around 2 billion years ago. So, while the dinosaurs were around 65 million years ago, these fossils show that it was about 1.5 billion years ago that they existed.