The 7 Kingdoms of Life Explained: Which Are Eukaryotic & Prokaryotic?

The seven kingdoms of living things are divided into two major groups: Prokaryotes and Eukaryotes.

There are two prokaryotic kingdoms and five eukaryotic kingdoms.

There are huge fundamental differences between the ways these two groups go about living.

Here is just the briefest of distinctions.

Eukaryotes

Eukaryotes have a separate membrane-bound nucleus, numerous mitochondria and organelles.

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 specialized in their activity.

Organelles include things such as Golgi Apparatus (Body), Mitochondria, Ribosomes, Lysosome and Vesicles and of course the Nucleus.

cell from the eukaroytic kingdom
Eukaroyte cell, with clear nucleus (red) and ovoid shaped organelles

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

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 a prokaryotic cell.

cell from the prokaryotic kingdom
Prokaryote cell with no nucleus or organelles

Though some bacteria have internal membranes as sites of metabolic activity, these membranes do not enclose a separate area of the cytoplasm.

There are also many other differences between prokaryotic and eukaryotic cells.

Eukaryotic Kingdoms and Prokaryotic Kingdoms

The next level down of classification is into Kingdoms.

Older books will teach that there are two Kingdoms, Plants and Animals.

Books produced towards the end of the last century will generally list six Kingdoms.

As of 2015, and the Publication of “A Higher Level Classification of All Living Organisms” by Ruggiero et al. seven kingdoms are now recognized.

The changes have resulted from better information collected from SEM imaging and DNA analysis.  However even this pattern of organisation is is not finished and there may well be changes in the future.

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 the seven kingdoms of life.

This will hopefully link, in time, to more information, including more terminology:

The Seven Kingdoms of Life

KingdomWhen EvolvedStructurePhotosynthesis
Prokaryotic:
Bacteria3 to 4 billion years agoUnicellularSometimes
Archaea3 to 4 billion years agoUnicellularNo
Eukaryotic:
Protozoa1.5 billion years agoUnicelularNo
Chromista1.2 billion years agoUnicellularOriginally, but sometimes lost; Chlorophyll c
Fungi1 billion years agoUnicellular or MulticellularNo
Animalia700 million years agoMulticellularNo
Plantae500 million years agoMulticellularYes; Chlorophyll a, b, and c

The Chromista and three multicellular eukaryote kingdoms all evolved, as best we understand, from the the protozoa. The two kingdoms of unicellular eukaryote organisms are considered to be polyphyletic. Meaning that they do not necessarily represent a single coherent clade taxonomically.

While the three multicellular kingdoms are all quite distinct, they share some characteristic and not others. Overall most scientists these days consider the fungi to be more closely related to animals than plants. The table below highlights the major differences between the three kingdoms, but does not mention characteristics that are shared by all three to some extent, such as having some members that can reproduce asexually.

The Three Multicellular Kingdoms.

CharacteristicKingdom PlantaeKingdom AnimaliaKingdom Fungi
Cell WallCelluloseAbsentChitin
ReproductionGametes or SporesGametesSpores
MitosisOpenOpenOpen or closed
Cellular differentiationIn whole organismIn whole organismOnly for fruiting bodies
Haploid cells vs Diploid cellsMost body cells diploidMost body cells diploidMost body cells haploid
Food AcquisitionAutotrophicHeterotrophicHeterotrophic
ChlorophyllPresentAbsentAbsent
Food StorageStarchGlycogenGlycogen
Motile (the whole organism can move itself)NoMostly yesNo

 

What Next?

You’re probably thirsty for more information, right? Maybe you’d like to learn more about Taxonomy.

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Gordon Ramel

Gordon is an ecologist with two degrees from Exeter University. He's also a teacher, a poet and the owner of 1,152 books. Oh - and he wrote this website.

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