Animal Kingdom Classification

The scientific classification of animals is a very detailed, Latin laden subject of study. If you are interested in the animal kingdom classification, you have come to the right place. The information in this article will surely help you make a chart for your little child about the classification of various animal species on earth. That should help him/her learn to identify the various animals that roam the Earth.

Animal kingdom classification is not a job for the faint-hearted, for it is a really long list of classes and sub classes, all of which are named in Latin. Makes me wonder why all the great scientists, biologists and physicians only catered to the Latin masses. Oh well, doesn't matter, what's done is done! This classification of the animal kingdom is segregated into phylum or classes which are in turn bifurcated into sub classes or subphylum. Let us begin our animal classification journey that attempts to classify all animals ranging from single-celled microorganisms to highly complex multi-celled organisms. It will definitely not be easy to capture 3.5 billion years of evolution in one small article, but let's give it a shot. My attempt at this categorization should help you with the basics, that you wish your child to know. Try not to baffle him/her with too much Latin, just get him/her to recognize all the animals and that's enough to make you proud.

Please note that this 'classification of animals' article will only explain the main phyla and not the class, order, family, genus and species. We will leave those for another article. The phyla are the segregation of all animals into smaller recognizable groups based on some unique characteristics that are found in them. Once you are familiar with the phylum you should automatically be able to gauge which animals fall into which one.

Phylum Protozoa - Primitive Animals


This phylum consists of unicellular, usually microscopic, water creatures like amoebae. The common points between all creatures listed under this phylum are:
All protozoans move with the help of false feet, known as pseudopodia.
Small hairlike structures called cilia help in free water locomotion.
Most protozoans have tails, which are again used for movement.
Protozoans reproduce by the mechanism of binary fission, also known as mitosis.

Phylum Porifera - Sponges


This phylum consists of simple multicellular animals that are mostly found in aquatic habitats. Their unique characteristic is that their cells are held together so loosely that they do not form tissues. Most sponges have pores known as ostia found all over the body and have a large opening on the tops, called an osculum. They have a canal that supports the intake of food and oxygen, and have a support system made up of tiny needle like formations of silica, spongin fibers and calcium. Amazingly, the reproduction in this segment of the animal kingdom may be sexual, asexual or even budding. Some examples of porifera are: sycon, spongilla and euplectella.

Phylum Coelenterata - Cnidaria


Mostly found in marine habitats, the animals in this phylum have a two-layered body that is symmetrical. The outer body layer has stinging tentacles that can release venom into the victim's body. The inner body consists of a gastro vasular cavity. This group usually consists of two types of animals (zooids), namely the polyps (fixed, solitary or colonial life) and medusae (free-swimming). Reproduction is by budding (asexual) in the polyps and is sexual with the medusae. All types of sea anemones are a part of this classification. This group also includes corals, that have an exoskeleton of lime.

Phylum Platyhelminthes - Aschelminthes


This is a phylum that includes all the animals once included in the Aschelminthes phylum, that has now been declared obsolete. Therefore, this phylum includes all animals like the flatworms and the threadworms. The animals in this phylum can be segregated into three groups:
The free-living class named Turbellaria.
The parasitic flukes that fall in the class Trematoda.
The parasitic tapeworms that consist of the class Cestoda.
The animals in this phylum are triploblastic organisms, that are mostly parasitic in nature and show bilateral symmetry. Most animals in this phylum have only one body cavity, that serves as both the mouth and the anus. Both males and the females have both male and female organs on them. Planaria, liver fluke and tapeworms also come under this segmentation of animals.

Phylum Nematoda - Ascaris


There are numerous species that fall under this phylum and they consist of most roundworms and eelworms. The thousands of eggs that they lay, form cysts and await ingestion. Some of the most important species that fall under this phylum are:
Lungworms that cause Hoose.
Hookworms, which are usually the worms that affect school children.
Potato eelworms and other stomach worms.
Phylum Annelida - Segmented Worms


This group consists of all the segmented worms, like earthworms, and leeches. Most segmented worms have bristles known as Chaetae, on each segment, that help them move. Segmented worms are mostly found in moist soil, though they can also inhabit freshwater and the sea. These worms have soft bodies that are triploblastic and follow a bilateral symmetry. While reproduction is usually sexual, they have another unique way of reproduction - asexual reproduction through rejuvenation. By regrowing broken segments, these worms can effectively reproduce. Other examples of annelid worms are sandworms and aphrodites (sea mouse).

Phylum Arthropoda - Jointed Legs


With nearly a million species (almost 80% of the animal kingdom) that are a part of this phylum, this can be said to be the largest one. All arthropods have jointed legs and a visible exoskeletons that shed periodically. Examples of arthropods are: scorpions, spiders, shellfish and crustaceans, insects, woodlice, centipedes and millipedes. Arthropods have a bilaterally symmetrical body shape, that is segmented into parts like the head, thorax and abdomen. All arthropods possess jointed legs that enable easy walking, swimming, feeding and feeling. They have a small blood filled body cavity; and respiration takes place with the help of lungs, book lungs and tracheae. Even prawn and bees fall under this phylum.

Phylum Mollusca - Molluscs and Snails


Molluscs include: slugs, snails, squids, mussels, clams and even octopuses. These generally have one foot (I said generally so you can excuse the squids and the octopuses) that excretes a slimy mucus. They possess a rasping tongue that can rip off materials much stronger than them. Though they are mostly found in aquatic habitats, they can also be found on land. Those living in water breathe through gills, while those living on land have fully developed lungs. Mollusks have distinct sexes.

Phylum Echinodermata - Star Fish


The echinodermata phylum consists of animals like the asterias (star fish), echinus (sea urchin), holothuria (sea cucumber) and antedon (feather star). Most of these animals are sea creatures with a symmetrical body that is either star-shaped, spherical or elongated. Most of them have a spiny exoskeleton and most have no proper head. Locomotion is achieved with the help of tubed feet and both the sexes are separate.

Phylum Chordata - The Most Known Phylum

This phylum basically belongs to the animals that can be called vertebrates or those that are closely related to vertebrates, namely the hemichordates. Chordates are divided in many subphylums, namely: amphibians, reptiles, mammals, marsupials, birds, fish, etc. Let us look at a few of these to understand more on chordates.

Class Mammalia - Mammals


These have hair or fur, are capable of regulating body temperature, give birth to fully formed babies and produce milk to feed their young. Examples of mammals are: monkeys, dogs, elephants, hippopotamuses, kangaroos marine mammals like whales, dolphins, squirrels and other rodents, such as rats, and marsupials like koalas, and even humans.

Class Amphibia - Amphibians


Amphibians lay eggs, usually in water and breathe through a combination of lungs, gills and skin. They cannot regulate their body temperatures and can live both, on land and in water. The amphibians are divided into three types like: 1) Caecilians, 2) Frogs and Toads, and 3)Salamanders.

Class Reptilia - Reptiles


Reptiles have roamed the earth since before the age of the dinosaurs and adapt well to changes in the environment. Dinosaurs were actually a group of reptiles known as dinosauria. Examples of reptiles are alligators, crocodiles, lizards, snakes, tortoises, etc. Though these are air-breathing animals, they can also live in water, but for very short durations (they need to come up above the water level in order to breathe). Reptiles cannot regulate body temperature and they lay eggs.

Class Aves - Birds


There are over 8000 different species of birds and some examples of them include parrots, sparrows, pigeons, geese, and sea gulls. The characteristics that are only unique to birds are that they have feathered wings, which enable them to fly, have beaks rather than teeth and light bones that make them light enough to fly. They can breathe even at high altitudes and lay eggs to give birth to their young.

Fish


Water is a home to more than 20,000 different fishes, some that are not even known yet. They have gills and they lay eggs. Fish used to be classified under the class Pisces, but that convention is not used anymore.

Some examples of fish are sharks, goldfish and herring.

There are many more divisions and subdivisions of animals, but I will stop my article on classification of animal kingdom here. Hope the article has helped you with learning all the animal kingdom classifications that you were yet unaware of.