Maharashtra Board Class 10 Science Part 2 Chapter 6 Animal Classification PDF Download

Animal Classification

Which criteria are used for classification of organisms?

You have studied the classification of living organisms in earlier classes. The living organisms present around us are mainly plants and animals. We have studied the criteria of their classification. With the help of that, complete the following chart.

Living organisms are divided into five kingdoms: Monera, Protista, Fungi, Plantae, and Animalia. Some are unicellular organisms and some are multicellular organisms.

How The Plants Are Classified?

We have studied the plants classification in last year. It helped us to understand the diversity of plants around us.

You must be looking varieties of animals around you. Some animals are too small whereas some are too big. Some animals are terrestrial whereas some are aquatic. Some animals crawl on land, some swim in water whereas some fly in air. Some animals have scales on skin whereas some have feathers or hairs. In this way, there is huge diversity among the animals too. According to recent studies, estimated number of animal species on earth is approximately 7 millions. It is impossible to study each and every species. However, if groups and sub-groups of animals are formed depending upon the similarities and differences, it will make it very easy to study such vast variety of animals.

Teacher's Note

Animal classification helps us understand the huge diversity of animals in nature. Just like we organize our school students by classes and sections, scientists organize animals into different groups.

Exam Trick

Remember: Diversity = Different groups. Think of your school - we have Class 1, Class 2, Class 3. Similarly, animals are divided into different phyla and classes. Just learn the main groups and their special features.

Points to Remember

There are about 7 million animal species on Earth.
Animals are grouped based on similarities and differences.
Classification makes it easy to study so many animals.
Each group has special characteristics.
Scientists divide animals into Kingdom, Phylum, Class and other levels.

Classification Of Living Organisms

History Of Animal Classification

Formation of groups and sub-groups of animals depending upon similarities and differences among animals is called as animal classification.

Benefits Of Animal Classification

Study of animals becomes convenient.

Study of few animals from a group helps to understand about that entire animal group.

It gives idea about animal evolution.

Animals can be easily identified with great accuracy.

It helps to understand the relationship of animals with other living organisms.

It helps to understand the habitat of each animal and its exact role in the nature.

It helps to understand various adaptations shown by animals.

Time to time, different scientists have tried to classify the animals. Greek philosopher Aristotle was the first to perform the animal classification. Aristotle classified the animals according to the criteria like body size, habits and habitats. Further, as per the new developments in sciences, references were changed and thereby the criteria of animal classification too. Classification proposed by Aristotle is known as 'Artificial method'. Besides Aristotle, artificial method of classification was followed by Theophrastus, Pliny, John Ray, Linnaeus, etc. Later on, 'Natural system of classification' was followed. Natural system of classification was based on various criteria like body organization, types of cells, chromosomes, bio-chemical properties, etc. By the time, system of classification based on evolution was also brought into practice. It was used by Dobzhansky and Meyer. Recently, Carl Woese has also proposed the animal classification.

Teacher's Note

Aristotle was the first person to classify animals. His method was simple - he looked at size, habits and where animals lived. Today, scientists use more advanced methods with many more details.

Exam Trick

Remember: Aristotle = First classifier. Artificial method = old way (size, habits, habitat). Natural method = new way (cells, evolution). Just know these names and their differences.

Points to Remember

Aristotle was the first to classify animals.
Artificial method used body size and habits.
Natural method used cells and chromosomes.
Evolution-based classification came later.
Scientists keep improving classification methods.

Traditional Method Of Animal Classification

Traditionally, depending upon presence or absence of the notochord, the animal kingdom has been divided into two groups - Non-chordates and Chordates.

A. Non-Chordates: Characters Of Non-Chordate Animals

Body is not supported by rod-like notochord.

Pharyngeal gill-slits are absent.

Nerve cord; if present, it is on ventral side. It is solid and paired.

Heart, if present, it is on dorsal side.

Non-chordates are classified and divided into ten phyla. Those phyla are: Protozoa, Porifera, Coelentarata (Cnidaria), Platyhelminthes, Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata and Hemichordata.

Teacher's Note

Notochord is a special rod in the body. Animals without it are non-chordates. Most common animals like insects and worms are non-chordates. Only fish, frogs, birds and mammals have notochord or backbone.

Exam Trick

Remember: No notochord = Non-chordate. Notochord = support rod. Insects, worms, sponges have no notochord. Fish, frogs, birds, humans have notochord or backbone.

Points to Remember

Non-chordates do not have a notochord.
They have no pharyngeal gill-slits in most cases.
Their nerve cord is on the ventral (bottom) side.
There are ten phyla of non-chordates.
Most animals on Earth are non-chordates.

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