WHAT ARE INVERTEBRATES?

Invertebrates Classification

Some invertebrate phyla are:

Phylum Protozoa

Phylum Porifera (Sponges)

Phylum Cnidaria (Coelentrata) 

Phylum Ctenophora :

Phylum Platyhelminthes

Phylum Aschelminthes (Nematoda)

Phylum Annelida (Segmented worms)

Phylum Arthropoda

Phylum Mollusca

Phylum Echinodermata

Phylum Protozoa

• Members of this phylum are commonly known as sponges.
• Habitat - They are mostly marine, few are found in fresh water. 
• Body symmetry - mostly are assymetrical animals, no definite shape to the body.
• Level of organization - These are primitive animals, multicellular with cellular grade of organization. 
• Digestion - Digestion is intracellular.
• Reproduction-  Reproduction of both means sexually as well as asexual.
• Asexually by mean of binary fission,by budding etc.
• Sexually by mean of conjugation.
• Examples- Paramecium,Amoeba,plasmodium etc.

WHAT ARE INVERTEBRATES?

List of Invertebrates

Invertebrates are the most diverse organisms present on earth. Almost 95% of the animal populations are of the invertebrates. Based on the International Union regarding Conservation of Nature at the time of 2009 more than 1.3 million invertebrates were identified. Invertebrates make up around 75% of the recognized species on Planet. 

The actual number of invertebrates is unknown, there are several predictions that there may be tens of millions of invertebrates, majority being the insects. New species of invertebrates are being discovered regularly, another worrying fact is that there is insufficient information about these organisms, the invertebrates might be going extinct and the scientists would never know that they even existed. 

Below are a list of invertebrates - 

Crustaceans, Centipedes, Ants, Wasps, Spiders, Locusts, Honey bees, Termites, Cockroach, Grasshoppers, Crickets, Stick insect, Mantis, Crabs, Sponges, Starfish, Unio, Leeches, Earthworms, etc.

WHAT ARE INVERTEBRATES?

Characteristics of Invertebrates

:-
General characteristics of invertebrates are as follows:

• The main characteristic that separates invertebrates from other organisms is the absence of the spinal column and backbone.
• They are multicelluar organisms, they completely lack cell walls.
• They are devoid hard bony endoskeleton. 
• Due to the lack of complex skeletal systems, some invertebrates tend to be slow and small in nature. 
• Due to the lack of the backbone and complex nervous system the invertebrates cannot occupy mulitple environments, though they are found in the harshest of the environments. 
• Invertebrates live all over the world in various habitats.
• Body is divided into three parts - head, thorax and the abdomen.
• They do not have lungs for respiration.
• Respiration is through skin.
• Some invertebrate groups possess a hard, chitinous exoskeleton. 
• Most of them have tissues, that are specific organization of cells.
• Most of them reproduce sexually by the fusion of the male and female gametes. 
• Few invertebrates like the sponges are sedentary, but most of the organisms are motile. 
• Most invertebrates are organized with symmetric body organization.
• They can not make their own food, are heterotrophs.

INVERTEBRATES

What are Invertebrates?

Invertebrates are the animals that do not have a backbone or the vertebral column.Animals without the notochord are invertebrates. Most of the animals are invertebrates. The term invertebrates is a prefixed form of a Latin derived word 'Vertebra'. 'Vertebra' means joint in general, specifically it means 'the joint of the spinal column of the vertebrate'. It id coupled with the prefix "in" meaning not or without, which conveys the meaning 'those that lack veterbrae'.

Invertebrates are the most diverse group having about 12 million live species. Most of the animals on earth are invertebrates. They are cold-blooded animals; their body temperature depends on the temperature of the atmosphere.

WHAT ARE INVERTEBRATES?

Invertebrates:-

Invertebrates are the most abundant organisms on earth. They occupy almost all habitats, they can be found crawling, flying, swimming or floating. Invertebrates are the animals without backbone. These animals do not have internal skeleton made of bone. They play a vital role in the earth's ecosystem.

About 99 per cent of the known organisms are invertebrates. Out of the planets estimated 15-30 million species about 90% of the animals are invertebrates. These come in may shapes and sizes and provide services that are vital for our survival.

The most common vertebrates include sponges, annelids, echinoderms, molluscs and arthropods. Arthropods includes insects, crustaceans and arachnids.