Difference between vertebrates and invertebrates

What are vertebrates?

Vertebrates are animals with a spinal column and an elaborate skeletal structure.

Characteristic traits of vertebrate animals

Vertebrates have the following characteristics:

1. All vertebrates have muscles and skeletons that help them to move around easily and perform complex moves.
2. All vertebrates also have an endoskeleton, which consists of the bones that are inside a body which gives them their shape and allows them to stand erect.
3. All vertebrates have some or all of these systems : muscular system, skeletal system, excretory system, immune system and nervous system, and skin covered with scales, fur, hair, or feathers.

Classification of vertebrates

Vertebrates are further classified into five classes. They are:

1. Pisces – fishes

1. They are cold-blooded animals
2. They have streamlined body
3. They have gills to breathe and fins for movement
4. In most of the cases, the body is covered with scales which provide protection to the body

Example – Goldfish, Seahorse, Shark

2. Amphibia – frogs and salamanders

1. They are cold-blooded animals
2. They can live both on land and in water
3. They breathe through both lungs and moist skin
4. They reproduce only in water

Example – Toad, Frog, Salamander

3. Reptilia – lizards and snakes

1. They are cold -blooded animals
2. They live on land
3. They breathe with the help of lungs
4. They have dry and scaly skin
5. They lay eggs

Example – Snake, Turtle, Crocodile

4. Aves – birds

1. They are warm blooded animals
2. Their body is covered with feathers
3. Their forelimbs are modified into wings
4. They breathe through lungs
5. Their bones are hollow
6. They lay eggs

Example – Pigeons, Parrot, Peacock

5. Mammals – animals with mammary glands

1. They are warm blooded animals
2. They breathe through lungs
3. They give birth to babies
4. They have mammary glands to produce milk

Example – Human, Dog, Cat

What are invertebrates?

Invertebrates are animals without a spine. They have no vertebrae.

Characteristic traits of invertebrate animals

Invertebrates have the following characteristics:

1. They are multi-cellular and all the cells are assigned different tasks
2. They have no cell walls
3. They reproduce by two reproductive cells or gametes

Classification of invertebrates

1. Sponges – poriferans

1. They are known as sponges
2. They live in salt water fixed to some object
3. Their body is covered with pores through which their food enters

Example – Sycon, Spongilla

2. Cnidarians

1. They live in the marine habitat
2. The body is like a tube with one opening called mouth
3. Mouth is surrounded by tentacles that help in capturing prey
4. They have a radially symmetrical body

Example – Hydra, Jellyfish

3. Platyhelminthes – flatworms

1. They can be found in marine/fresh water
2. They have flat, ribbon shaped body
3. The body is bilaterally symmetrical
4. The body has a single opening
5. Most of them are parasites

Example – Tapeworms, Liverfluke

4. Nemathelminthes – roundworms

1. They are found in fresh/marine water or on land
2. They have a thread like, rounded body
3. They have an unsegmented body
4. Their body has two openings, mouth and anus
5. The body is bilaterally symmetrical
6. Most of them are parasites and reproduce sexually by laying eggs

Example – Pinworm, Ascaris

5. Annelids – segmented worms

1. They are found in marine and fresh water
2. They have segmented bilaterally symmetrical body
3. They have a body cavity
4. They have special organs of excretion known as Nephridia

Example – Earthworm, Leech

6. Arthropods – animals with jointed legs

1. They have a segmented, bilaterally symmetrical body
2. Their body is divided into three parts – Head, Thorax and Abdomen
3. It is covered by a tough outer covering called exoskeleton
4. They have jointed appendages

Example – Ants, Honeybee, Scorpion, Spider

7. Molluscs – soft bodied shelled animals

1. Animals have a soft unsegmented body with an external hard shell

Example – Squid, Snail, Octopus

8. Echinoderms – spiny-skinned animals

1. They live in the marine environment and have spines all over the body
2. The body is radially symmetrical
3. Their body has two openings, mouth and anus
4. They have tube like feet having suckers

Example – Starfish, Sea Urchins

5 Fun facts about vertebrates and invertebrates

1. Different types of vertebrates have different numbers of vertebrae. Humans have 33 vertebrae, an alligator has 66 vertebrae, and a snake has about 500 vertebrae!
2. Vertebrates have advanced nervous system, therefore, they are much more intelligent than invertebrates.
3. Invertebrates cannot make their own food, and therefore, they have to feed off other things to get their energy.
4. Mammals and birds are warm-blooded, which means that they can make their own body heat even when the temperature outside is low. The body temperatures of warm blooded animals usually stay the same.
5. The body temperature of the cold-blooded animals, like reptiles, fish and amphibians depends on the temperature outside. For example, when the sun sets at night, their bodies become cold and when the sun rises, their bodies become warmer.