1.4Classification and characteristics of animals.
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characteristics of animals. |
i. Invertebrates
ii.Vertebrates
ii. Invertebrates
Animals that do not have backbones are called Invertebrates. Examples of invertebrates are earthworm, spider, crab, scorpion, cockroach, butterfly, snail, and starfish etc.
il. Vertebrates
Animals that have vertebral coloumn or backbone are called vertebrates. Vertebrates has a system inside bones called an endoskeleton. The vertebral coloumn and other bones provide firm support and protect internal organs. Many muscles are attached to the skeleton and make movement possible.
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1.5 Classification of vertebrates
The vertebrates are further classified into five groups.
1. Fish
2. Amphibians
4. Birds (Aves)
5. Mammals
1:-Fish
Fish is the largest group of vertebrates.All fishes live in freshwater and slat water.They are called aquatic animals. Following are the characteristics of fish.
1:-Fish have fins and tail which help them to swim.
2:- Bodies of most fish are covered by scales.
Exemples of fish are, shark fish, solomon fish, and trout fish, etc.
2. Amphibians
It is an animal that can survive on both water and land. They lay eggs in the water. In fact, the term amphibian is derived from the Greek word amphibious, meaning 'double life'. The characteristics of amphibians are as follows:
1:- They have soft and moist skin.
2:-They have four legs.
3:- They have gills for respiration during early stage of their life. But when they mature, the gills are replaced by lungs.
4:- They lay eggs in water or on moist places.
Examples of amphibians are frog, toad, and salamander etc.
3. Reptiles
The reptiles are called reptiles.Reptiles are found in different shapes, sizes and colours. Most of the reptiles live on land some can live in water. Following are the characteristics of reptiles.
1:- They move by crawling.
2:- They have lungs.
4:- They lay eggs on land.
5:- They have thick, dry and scaly skin.
Examples of reptiles are snakes, turtles, lizards and crocodiles etc.
4. Birds (Aves)
The vertebrates which have feathers and wings are classified as birds. Most of the birds can fly but some birds such as kiwi, penguin, and ostrich can not fly. Most of birds live on land. Some birds can swim in water like penguin.
Following are the characteristics of birds.
i.Their bodies are covered with feathers.
ii. They have a pair of pro and legs.
iii. They have strong beaks but no teeth.
iv. They have hollow light bones which enable them to fly.
v. They lay eggs.
Examples of birds are crow, pigeon, kite, kiwi, penguin, and parrot etc.
5. Mammals
Mammals is the most advance group of animals. Most mammals live on land. However, some live in water, such as dolphins and whales. The mammalian body system is designed to support activities such as running, swimming, climbing, hopping and flying.
Following are the characteristics of mammals.
i. Their bodies are covered with hair.
ii. They give birth to young ones.
iii. Except humans, nearly all mammals have tails.
iv. They have external ears.
Examples of mammals are human being, cow, elephant, whale, dolphins,bat and deer etc.
1.6 Difference between Vertebrates and Invertebrates
The differences between vertebrates and invertebrates are listed below:
Vertebrates
They have vertebral column their bodies.
They have bones in their bodies. They have
Their eyes are simple.
They have well developed nervous system.
Cows, snakes, elephants, dogs, and humans, etc. are the examples of vertebrates.
Invertebrates
They have not vertebral column in their bodies.
They usually do not have bones in their bodies.
Their eyes are either simple or compound.
They have not well developed nervous system.
Worms, snail, insects, and starfish, etc. are the examples of invertebrates.
1.7 Worms and Insects
Invertebrates are divided into many groups. Among them there are two important groups i.e worms and insects.
Worms
Their bodies are divided into many segments. They have flat, soft cylindrical bodies. They have no legs and wings. They have hooks, bristles or other sucker organs which help them to attach with the bodies of other animals.
Examples of worms are liver fluke, leech, roundworms and tapeworms
etc.
Insects
(They have three pairs of jointed legs, one pair of compound eye, two pairs of wings and one pair of antennae, Their bodies are divided into three main parts; head, thorax and abdomen. Their bodies are covered with durable shell called exoskeleton.
Examples of insects are housefly, ants, termites, and cockroach etc.
1.8 Classification and characteristics of plants
Biologists have divided the plant kingdom into two groups on that whether they produce flowers or not. These groups are called plants and non-flowering plants.
i. Flowering plants
Plants that produce flowers are called flowering plants.They produce fruits.Their seeds are enclosed in their fruits. Most of the common plants around us are flowering plants. Examples are apple, guava, pea, radish, carrot, chili, onion, mustard, sunflower and rose etc.
II. Non-flowering plants
Plants which never flowers are called as non-flowering plants, They do not produce flowers and fruits. Their seeds are produced in special structures called cones. Mosses, ferns, fir and pinus (chir) are examples of non-flowering plants.
