The six kingdoms of living things are divided into two major groups, Prokaryotes and Eukaryotes. There are two prokaryote kingdoms and four eukaryote kingdoms.
There are huge fundamental differences between the ways these two groups go about living. Here is just the briefest of distinctions.
Eukaryotes have a separate membrane bound nucleus, numerous mitochondria and other organelles such as the Golgi Body within each of their cells. These areas are separated off from the main mass of the cell's cytoplasm by their own membrane in order to allow them to be more specialised. The nucleus contains all the Eukaryote cell DNA for instance and the Mitochondria are where energy is generated. The exception to this rule are red blood cells which have no nucleus and do not live very long.
|Prokaryotes do not have a nucleus, mitochondria or any other membrane bound organelles. In other words neither their DNA nor any other of their metabolic functions are collected together in a discrete membrane enclosed area. Instead everything is openly accessible within the cell, though some bacteria have internal membranes as sites of metabolic activity these membranes do not enclose a separate area of the cytoplasm. See Cells the Basis of Life|
There are many other differences between Prokaryotes and Eukaryotes which you can find out about by reading the sections on the two groups that make up the Prokaryotes. See below.
The next level down of classification is into Kingdoms, older books will teach that there are 2 Kingdoms, Plants and Animals but a more modern understanding is to use 6 Kingdoms
Unfortunately Botanists, Mycologists and Zoologists, who study the three kingdoms you will be most concerned with, do not always use the same terminology below kingdom level, though much of it is the same. Here you will find a brief description of each Kingdom which will link, in time, to more information, including more terminology.
|Bacteria||3 to 4 billion years ago||Unicellular||Sometimes|
|Archaea||3 to 4 billion years ago||Unicellular||No|
|Protista||1.5 billion years ago||Unicellular||Sometimes|
|Fungi||1 billion years ago||Unicellular or Multicellular||No|
|Animalia||700 million years ago||Multicellular||No|
|Plantae||500 million years ago||Multicellular||Yes|