Invertebrate and vertebrate animals

In the animal kingdom, we can classify animals into two main categories based on the presence or absence of the spine. But that’s not all, there are many more differences between invertebrates and vertebrates and today we will teach them to you. In this article we will leave you a great amount of information where you can see and explore how these classes of organisms differ from each other.

What are invertebrates

We can simply identify invertebrates as animals that do not have a backbone . They can be found almost everywhere, even from the hottest deserts to the deepest sea beds, and also from the darkest caves to the highest mountains.

Therefore, invertebrates are animals without a skeletal system , that is, they do not have a rigid body structure (most of them) and, therefore, cannot grow very much. In terms of anatomy, most invertebrates have an open circulatory system where blood flows into the open cavity and they have a simple respiratory system .

To make up for this lack of an internal skeleton, most invertebrates have an external skeleton to protect their soft internal body. These materials are usually made from chitin, a derivative of glucose. Invertebrates make up more than 95 percent of all species on earth. Some main examples are annelids, arthropods, bivalves, coelenterates, echinoderms, squid, sponges, snails, and octopuses.

• Mollusks (snails, octopus, squid and clams).
• Arthropods (insects, spiders, crustaceans such as shrimp, crabs, lobsters).
• Echinoderms (starfish, sea urchins, sea cucumber).
• Annelids (earthworms, leeches).
• Protozoa (single-celled organisms that include amoebae and paramecia.

What are vertebrates

Vertebrates are the most advanced species in our animal kingdom. These animals possess a well-defined internal skeletal system that includes the spine. In humans, the spinal cord runs in the body between the caudal and cranial regions and thus connects nerve tissues.

Vertebrates have more complex and specialized organ systems when compared to invertebrates. Organ systems like the respiratory systems are very complex due to many additional functions. Even the sensory organs present in vertebrates are advanced, which helps them adapt to their respective environment.

On average, the total count of vertebrates that exist on planet earth is around 57,000 to 58,000 . Some main examples are mammals, birds, fish, reptiles and amphibians, etc.

• Fish (Goldfish, Wels catfish, Barramundi, Atlantic Cod, etc.).
• Amphibians (frog, salamander, caecilian, amphibian, etc.).
• Reptiles (snakes, turtles, lizards, chameleons, crocodiles, etc.).
• Birds (Parrot, Pigeons, Owl, Swallow, Finches, Sparrow, Penguin, etc.).
• Mammals (rodents, cetaceans, bats, primates, bears, deer, humans, lions, cows, bison, etc.).

After seeing the corresponding definitions and the comparison chart between invertebrates and vertebrates, here are some more specific differences:

Differences based on habitat

Both types of animals live in many types of habitats. But, vertebrates can essentially adapt easily to any type of habitat . This is possible due to the nervous system and the internal skeletons of the same.

Differences based on classification

Vertebrates are classified into fish, amphibians, reptiles, birds, and mammals. On the other hand, invertebrates include sponges, coelenterates, true jellyfish, sea anemones, sea feathers, etc. Some more are echinoderms, worms, and arthropods, etc.

Differences according to size

Size is one of the notable differences between invertebrates and vertebrates. Invertebrates such as worms, shellfish, insects, etc. They are small and slow moving due to the lack of solid support. Vertebrates have a versatile support system, so they have the ability to develop larger and faster bodies than invertebrates.

Frequently asked questions about vertebrates and invertebrates

Q.1: Explain some characteristics of invertebrates.

Answer: One of the main characteristics is the absence of a spinal cord, which is why they lack a hard and bony internal skeleton. In some individuals, a tough outer structure called the exoskeleton is present. This also provides structural strength and protection against predators and the environment. They are mostly mobile, but there are exceptions such as the marine sponge.

Q.2: Explain some characteristics of vertebrates.

Answer: Vertebrates are more complex organisms compared to invertebrates. The main difference between these two is that the former have a solid backbone and internal skeleton. Also, some vertebrates have bones replaced by cartilage, as in sharks. A more defining characteristic of vertebrates is that they reproduce sexually.

Classification of vertebrates

Vertebrates are classified into five classes. They are:

1. Fish

• They are cold-blooded animals
• They have a streamlined body
• They have gills to breathe and fins to move.
• In most cases, the body is covered in scales that provide protection to the body.
• Examples: goldfish, seahorse, shark

2. Amphibians: frogs and salamanders

• They are cold-blooded animals
• They can live both on land and in water.
• They breathe through the lungs and moist skin.
• They reproduce only in water.
• Examples: toad, frog, salamander

3. Reptilia: lizards and snakes

• They are cold-blooded animals
• They live on earth
• They breathe with the help of their lungs.
• Have dry, flaky skin
• They lay eggs
• Examples: snake, turtle, crocodile

4. Birds – birds

• They are warm-blooded animals
• His body is covered with feathers.
• Its forelimbs are modified into wings.
• They breathe through the lungs
• Your bones are hollow
• They lay eggs
• Examples: pigeons, parrots, peacocks

5. Mammals: animals with mammary glands

• They are warm-blooded animals
• They breathe through the lungs
• Give birth to babies
• They have mammary glands to make milk.
• Examples: human, dog, cat

Classification of invertebrates

1. Sponges – poriferans

• They are known as sponges
• They live in salt water attached to some object
• Your body is covered in pores through which food enters.
• Examples: Sycon, Spongilla

2. Cnidarios

• They live in the marine habitat.
• The body is like a tube with an opening called the mouth.
• The mouth is surrounded by tentacles that help capture prey.
• They have a radially symmetrical body
• Examples: hydra, jellyfish

3. Flatworms – flatworms

• They can be found in marine / fresh water.
• They have a flat body in the shape of a ribbon.
• The body is bilaterally symmetrical.
• The body has only one opening.
• Most of them are parasites.
• Examples: tapeworms, liverwort

4. Nemathelminthes – roundworms

• They are found in fresh / marine water or on land.
• They have a rounded body like a thread
• They have an unsegmented body
• Its body has two openings, mouth and anus.
• The body is bilaterally symmetrical.
• Most of them are parasites and reproduce sexually by laying eggs.
• Examples: pinworms, roundworms

5. Annelids: segmented worms

• They are found in fresh and marine water.
• They have a bilaterally symmetrical segmented body.
• Have a body cavity
• They have special organs of excretion known as Nephridia.
• Examples: earthworm, leech

6. Arthropods: animals with jointed legs

• They have a segmented body, bilaterally symmetrical.
• Your body is divided into three parts: head, thorax, and abdomen.
• It’s covered in a tough outer shell called an exoskeleton.
• They have jointed appendages
• Examples: ants, bees, scorpions, spiders

7. Mollusks: soft-bodied animals with shells

• Animals have an unsegmented soft body with a hard outer shell
• Examples: squid, snail, octopus

8. Echinoderms: spiny-skinned animals

• They live in the marine environment and have spines all over their bodies.
• The body is radially symmetrical
• Its body has two openings, mouth and anus.
• They have feet like tubes with suction cups
• Examples: starfish, sea urchins

We have reached the end of the article, we hope you have been able to understand the differences between vertebrates and invertebrates and visit us again.

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