Back


This Knowledge Base, provided by Marine Themes, is not intended to be an authority on taxonomic order. It is intended to provide a basic knowledge of some of the more "obvious", though not necessarily common, animal species found in our database.

The Tree Of Life


All life on earth is classified according to a taxonomic order or hierarchy. From minute drifting planktonic plants to giant Sequoia trees, from single cell organisms to the mighty Blue Whale. This order is constantly being adjusted, changed, revised and "tweaked" as we gather more knowledge about life on our unique planet. Here, the Tree Of Life refers to the illustration of a tree with a base or stump (living organisms as opposed to non-living things such as minerals) branching up and out into a diverse array of living creatures and terminating in a single animal. (See the example below.)

Since there are so many living things, the order in which we place them becomes very complicated. However, it is possible for anyone to keep track of the structure, especially if we stick to the main "branches" on the Tree Of Life.

Animal life is initially divided into at least 20 or more main groups called Phylum. Examples of some phylum are Mollusca, Porifera, Arthropoda, Echinodermata, and Chordata. Mollusca is the group containing molluscs such as octopus, squid, snails, shells, etc. The Porifera phylum contain all the sponges. Chordata include fish, mammals (including humans), reptiles, etc.

For our purposes, we will group the various phylum into two divisions: Vertebrates and Invertebrates, animals with or without a spinal chord. Even this division is blurred as some animals, such as tunicates and salps, are regarded as vertebrates although in adult form they do not have a spinal chord.

The phylum Chordata can be split into two groups called Subphylum: Vertebrata or vertebrates and Tunicata. Tunicata includes those taxonomically pesky animals Tunicates, Salps, Lancelets and Larvaceans which we will quietly set aside for the moment. Vertebrates can be divided up into Classes and Orders. The Vertebrate Classes are Fish, Amphibians, Reptiles, Birds and Mammals. The Blue Whale has this taxonomic hierarchy or rank (including a number of additional specific divisions such as sub classes and sub orders):

Domain: Eukarya (Organism made of cells with a membrane containing a nucleus)
Kingdom: Animalia (Multi-cellular organisms, capable of locomotion, responsive to their environment & feed by consuming other organisms)
Phylum: Chordata (Having, at some stage of life, a notochord or a hollow dorsal nerve cord)
Subphylum: Vertebrata (Having vertebrae or backbone)
Class: Mammalia (Mammals having mammary glands, hair or fur, and endothermic or "warm-blooded" bodies)
Subclass: Theria (Giving birth to live young without a shelled egg)
Infraclass: Eutheria (Having a placental connection to the foetus)
Order: Cetacea (Whales, Dolphins & Porpoises)
Sub Order: Mysticeti (Whales with bristle-like baleen, not teeth)
Family: Balaenopteridae (The Rorqual whales with single blow hole and a dorsal fin)
Genus: Balaenoptera
Species: Musculus

This structure helps us to see how this animal fits into the overall hearty of living creatures or, as referred to here, the Tree Of Life. The taxonomic name for the Blue Whale, and any other animal for that matter, comes from the Genus and Species names. Therefore, the Blue Whale is known taxonomically as Balaenoptera musculus. In the Marine Themes database an animal is identified by the common name followed by the taxonomic name in brackets. i.e. Blue Whale ( Balaenoptera musculus). This is a syntax used by all reputable scientific publications.
Just to confuse matters a little more, biologists assign sub species names to the one species. This is often in response to genetic studies that show that a particular group of the one species is geographically isolated from another. Often, external differences are either invisible to the untrained eye (or the trained one for that matter) or minor (i.e. a constant shift in colour or size between groups, like the difference between a Kalahari Bushman hunter and a tall Swedish basketball player). However, the "publish or perish" mind set (also known as the "tall poppy gets the government grant" syndrome) sometimes backed up with compelling physical and/or genetic differences between animals has given rise to sub species. Again the Blue Whale example above has these sub species taxonomic names:

Subspecies 1: Balaenoptera musculus brevicauda (Pygmy Blue Whale in the Indian Ocean & South Pacific)
Subspecies 2: Balaenoptera musculus indica (Indian Ocean species)
Subspecies 3: Balaenoptera musculus intermedia (Southern Ocean species)
Subspecies 4: Balaenoptera musculus musculus (North Atlantic & North Pacific. The largest sub species)

Including the taxonomic name is important for one simple reason. Common names are not an accurate way to identify an animal. Take the Blue Whale as an example. In French it is called Rorqual Bleu, in Spanish it's Ballena azul. OK, they do translate back into English as Blue Whale. However, the taxonomic name is the same in all languages, irrespective of the alphabet used, even asian Kanji or European Cyrillic script. Also, in English the Blue Whale has many different common names such as Sulphur-bottom, Sibbald's Rorqual, the Great Blue Whale and the Great Northern Rorqual.

 

 

Home
Site Map
Contact Details