Invertebrates are animals without a backbone.They play a vital role in Earth's ecosystem. They are classified as: 1-Insects:Insects can be found just about everywhere:in our gardens and homes.Insects are invertebrates.They have three body parts-the head,the thorax and the abdomen-with three pairs of jointed legs,compound eyes and one pair of antenna.Examples are houseflies,cockroaches,ants,butterflies etc. 2-Worms:Worms have segmented bodies that have water inside to hold them up.Examples are earthworm and tapeworms.Flatworms and roundworms don't have segmented bodies.Invertebrates make up almost 97% of all known animal species on Earth.Some of them are insects and some are worms but some are neither insects or worms.
Natural classification of animals mention 2 types of animals according to their phylum. Vertebrates and Invertebrates are those 2 main types of animals. Vertebrates are the animals who do have a vertebral column and invertebrates are the animals who don’t have a vertebral column. We have discussed about vertebrates and its 5 types on Smart Science Pro.
Therefore, we’re going to concentrate on Invertebrates in this post.
A natural classification has few characteristics and all the classifications of this system are following those. So here are the features of this type of animals.
Characteristics of Invertebrates
Since now you realize who are invertebrates, it’s good to learn their other characteristics too. May be your science exam would ask these or you may want to clarify some animal’s type.
Made up of animal cells.
Don’t have a vertebral column or spinal cord or backbone.
Usually these are little and slowly moving animals.
Presence of no lungs to respire since they do it through the skin.
Invertebrates are heterotrophic since they can’t produce their own food.
Reproduction is through fission of gametes.
Some posses a hard exoskeleton.
Multicellular organisms live on many environments.
Invertebrates includes every animal that doesn’t belong to vertebrates group. There are 4 main types of invertebrates as mentioned below by Phylum.
Phylum Arthropods
Phylum Mollusca
Phylum Annelida
Phylum Coelenterata
Each group have their own characteristics and unique adaptations. I’ll explain each of them below.