Animals are multi cellular, eukaryotic living beings. They have some distinct features like ability to move, make sounds, collect food materials and other activities.
They are the dominant living beings on the earth. These include small animals like insects to intelligent large animals like human beings.
They differ from plants in their ability to move from place to place and dependent on others for their food. Most of them are dependent on plants while few are dependent on other animals.
They have brain which evolves further and they can make decisions.
They can be classified into different types based on their food requirements, habitats, size, reproduction, body anatomy etc.
Types of animals by evolution
- Sponges
- Coelenterates
- Worms
- Mollucs
- Arthopods
- Echinoderms
- Fishes
- Amphibians
- Reptiles
- Birds and
- Mammals (includes humans)
Sponges: These are multi cellular organisms mostly found in marine waters. The cells do not form a tissue so they have no organs.
Each cell in the body survives on its own but all the cells are intact. They have column shaped body.
Coelenterates: These animals are more evolved than sponges. They have tube like bodies and a mouth.
They even have tentacles (appendages) to swim. They move from one place to another in search of food and shelter.
Ex: Hydra which lives in fresh water.
Worms: These are biggest category of organisms. They exist as normal living organisms and also as parasites in other higher animals.
They have thread like or tape like body. They are slender and very long. They are of different types ex: Earth worms.
Arthopods (insects): These are animals which have joint legs. They are commonly called as insects. They are herbivorous and some of them are carnivorous. They are also parasites causing diseases to other animals.
They also act as parasites (lice). They are one the biggest category of animals available. They include house fly, mosquitoes, spiders, butter fly etc.
Echinoderms: This is a class of animals including starfish.
They live in sea and oceans.
Till echinoderms we come across invertebrate animals. From there on we see evolution of vertebrate animals.
Fishes: These are the animals well know to man. They are present in both fresh water and marine waters.
They breath will gills and swim with fins. They lay eggs and give birth.
Amphibians: These animals as the name indicates are able to live on both land and in water.
This group of animals include especially the frogs. They are carnivores and also herbivorous.
Reptiles: These animals are poisonous snakes, lizards and ferocious crocodiles. See the characteristics of reptiles.
They are mostly carnivores except tortoise. They live either on water or on land. Not on both.
Birds: These are the animals which have a special ability to fly. They can fly miles together due their strong fore limbs. From these animals and mammals we get the concept of warm blooded animals. They have constant body temperature irrespective of external climate conditions.
They are carnivores but can eat even plant material. They lay eggs and give birth to young ones.
Mammals: These animals are highly evolved of all. They give direct birth to young ones.
They feed the babies with milk from their mammary glands.
Types of animals based on anatomy.
- Based on vertebral column
a. Vertebrates. Have vertebral column, spine connecting brain
b. Invertebrates. No vertebral column
2. Based on body temperature.
a. Poikilotherms (changing temperature)
b. Isoltherms (constant body temperature)
3. Reproduction
a. Hermophrodites.
b. Male or female animals.
4. Respiratory system
a. Lungs
b. Gills.
c. Tracheae.
5. Progeny
a. From eggs
b. Direct birth.