Do you know what makes a butterfly different from a cockroach? Do you know whether or not they are related to each other and have shared characteristics? Well, Zoology is an area of biological science that deals with different animals. There are different types of animals with common traits as well as with the very different set of characteristics. In order for scientists to understand the characteristics of these animals, a classification of animal kingdom is necessary. It is mainly through this system of classification that you will be able to understand the relationship between different animals.
The standard classification system of the animal kingdom
There is a standardised classification system of the animal kingdom which is accepted across the world. This classification follows a certain pattern based on which the classifications are made. This science of the classification of animals in order to form a standardised and universally accepted structure is known as taxonomy. Let us take a look at them:
- The first step of standardised classification involves broadly grouping living organisms into kingdoms- like plants, animals, fungi etc.
- In the next step, the different animals of the animal kingdom are divided into phylum. There is a total of 40 phylum in case of the animal kingdom. This classification is done based on one very important feature of those animals, for example dividing animals into phylum based on whether or not they have a vertebrae.
- The next stage in the classification of animal kingdom delves deeper into details. In this case the phylum gets divided into classes based on certain characteristics of the animals, for example, under the phylum vertebrate, some are of the class mammal, some of the class amphibian, etc.
- Then comes the classification of the class into order like mammals like herbivores, omnivores etc based on finer shared characteristics.
- Order is then classified into families like within carnivores, canidae(family of dogs), Felidae(family of cats) etc. This grouping is done based on further similar characteristics.
- Then comes breaking down the families into groups called genus, for example, the Felidae or cat family is divided into Panthera, Puma etc.
- Then finally it is broken down into species.
Fun fact: You can tell the genus and species of an animal based on its scientific name. A scientific name generally contains two words- the first word indicates the genus and the second word the species. For example, take the scientific name of the animal tiger- Panthera Tigris. This means that the animal tiger belongs to the genus Panthera and to the species Tigris.
Detailed understanding of the classification of animal kingdom
Let us take a look at the following flowchart to understand the classification of animal kingdom:
Image Credits: Exploring Nature
The main division of the animal kingdom takes place based on the presence or absence of the notochord, nerve chord, pharyngeal gill slit, and the ventral placing of the heart. Those animals which have all these elements present are known as chordates and those in which these features are absent are known as non chordates.
It is important to remember here that chordates can be invertebrates as well because just the presence of the notochord at any stage of the development of the animal makes it a chordate whereas, it might not have a vertebral column.
Let us take a look at this chart to understand the standardised classification of animal kingdom:
This table takes a look at the three main sub phylum of the animal kingdom.
|Urochordata (also known as Tunicata)||1. Typically marine animals
2. Body is covered with a leather like covering.
3. Free swimming larvae
4. Presence of notochord in the larval stage of development in the tail
5. Typically hermaphrodites
6. Turns into sessile or immobile adults
Examples: Doliolum, Ascidians, Thaliacea etc.
|Cephalochordata||1. Large pharynx
2. Gill slits are present
3. Presence of notochord throughout the entire length of the body
4. Separate sexes
5. fish like in appearance
6. Marine animals
7. Generally lance shaped and hence known as lancelets
Examples: Epigonichthys, Branchiostoma
|Vertebrate||1. Presence of a developed vertebral column
2. Head is developed
3. Bony or cartilaginous endoskeleton
4. Cranium protects the brain
5. May be with or without jaws. The ones with jaws are known as Ganathostomata and those without, Agnatha
Now let us take a look at the main classes of the classification of animal kingdom:
|Cyclostomata||1. Jaws absent
2. Soft skin
3. No scales
4. Have mouths for sucking
5. No paired appendages
6. Mostly ectoparasites, i.e. a parasite that does not reside inside the body of the host
7. Endoskeleton is cartilaginous
2. Spindle shaped body, well suited to swimming
3. Presence of fins and scales(exoskeleton)
4. Cold blooded
5. Respiration takes place with the help of the gills
6. Bony or cartilaginous endoskeleton
7. Absence of eyelids
Eg: Rohu, Katla etc.
|Amphibia||1. Cold blooded
2. Both terrestrial and can live in freshwater
3. Two pair of limbs
4. Has digits but no claws
5. No exoskeleton is present
6. Protruding eyes with eyelids
7. Respiration takes place through moist skin
8. No exoskeleton
9. Ear drums are present
Eg. Frogs, salamanders etc
|Reptilia||1. Crawls on the ground
2. Cold blooded
3. Bony plates or scales are present on their dry skin
4. Digits with claws
5. No external ears
6. Neck is present
Eg. Snakes, lizards etc.
|Aves||1. Forelimbs are modified to form wings
2. The body is streamlined so that it can fly with minimum resistance
3. Warm blooded
4. Beak and neck present
5. Digits have claws
6. Feathers form the exoskeleton
Eg. Pigeon, crows etc.
|Mammalia||1. Warm blooded
2. Presence of mammary glands
3. Body divided into distinct, head, neck, trunk and tail
4. No external ear
5. Exoskeleton is formed with fur or hair
6. Digits might have nails or claws or hooves
Eg. Bats, humans etc.
This concise classification of animal kingdom will help you to understand the basic characteristics of the various animals that you see around yourself and be able to gauge their similarities and differences. Keep following TopprBytes for more!