Question

Differentiate between vertebrates and invertebrates.

Answer 1

Hint: Invertebrates include arthropods (insects, arachnids, crustaceans, and myriapods), annelid (earthworms and leeches), and cnidarians (hydras, jellyfishes, sea anemones, and corals) etc. The majority of animal species are invertebrates. Many invertebrate taxa have a greater number and form of species than the whole subphylum of Vertebrata.

Complete answer:
 In order to answer this question we need to know about vertebrates and invertebrates in detail.
All the animals on earth are classified into invertebrates or vertebrates. However, vertebrates have developed themselves with advanced organization of bodily structure and are more adjustable to all or any reasonable environment. Invertebrates are animals that neither possess nor develop a skeletal structure, derived from the notochord. This includes all animals except the Vertebrata.
Classification:
Invertebrates is classified into several main categories:
• Sponges (Porifera) • Comb jellies (Ctenophora) • Hydras, jellyfishes, sea anemones, and corals (Cnidaria) • Starfishes, sea urchins, sea cucumbers (Echinodermata) • Flatworms (Platyhelminthes) • Round or threadworms (Nematoda) • Earthworms and leeches (Annelida) • Insects, arachnids, crustaceans, and myriapods (Arthropoda) • Chitons, snails, bivalves, squids, and octopuses (Mollusca)
Vertebrates comprise all species of animals within the phylum (chordates with backbones). Vertebrates represent the overwhelming majority of:
Phylum- Chordata; Class: Sauropsida (reptiles and birds)
jawless fishes
jawed vertebrates, which include the cartilaginous fishes (sharks, rays, and ratfish)
tetrapods, which include amphibians, reptiles, birds and mammals
bony fishes
Subphylum Vertebrata
Palaeospondylus
Superclass Agnatha or Cephalaspidomorphi (lampreys and other jawless fishes)
•Infraphylum Gnathostomata (vertebrates with jaws)
Class Placodermi (extinct armoured fishes)
Class Chondrichthyes (cartilaginous fishes)
Class Acanthodii (extinct spiny "sharks")
Superclass Osteichthyes (bony vertebrates)
Class Actinopterygii (ray-finned bony fishes)
Class Sarcopterygii (lobe-finned fishes, including the tetrapods)
Superclass Tetrapoda (four-limbed vertebrates)
Class Amphibia (amphibians, some ancestral to the amniotes)—now a paraphyletic group
Class Synapsida (mammals and the extinct mammal-like reptiles)
Class Sauropsida (reptiles and birds)

Invertebrates lack the developed organs and skeleton system because of which they don’t have a rigid structure of a body. One of the main factors is that invertebrates remain small in size because of lack of network, loosely organized systems, and fewer growing muscles, which also make their motion slow. Annelids, Arthropods, Coelenterate are few samples of Invertebrates. However, Insects and Molluscs have an outer skeleton system. Other systems of a body like circulatory systems are open in many organisms and the heart is dorsally placed, sometimes there's one opening for feeding and defections, a systema respiratorium is diverse and may be as simple because of the diffusion process. They vary in their body symmetry like may be the radial or bilateral style of organization. The mode of feeding will be Parasitic or Heterotrophic.
First and foremost, vertebrates have the foremost advanced system of their body, which makes them suitable to survive in a very different environment. Vertebrates have a well defined internal skeleton system consisting of diverse bones and are meant to function differently. This skeletons system may be bony or cartilaginous. Vertebrates produce other organs like systems (gills and lungs), sensory organs and advanced systema nervosum too. One of the main factors is that invertebrates remain small in size thanks to lack of network, loosely organized systems, and fewer growing muscles, which also make their motion slow. Annelids, Arthropods, Coelenterate are few samples of Invertebrates. However, Insects and Molluscs have an outer skeleton system. Other systems of a body like circulatory systems are open in many organisms and the heart is dorsally placed, sometimes there's one opening for feeding and defections, a systema respiratorium is diverse and may be as simple because of the diffusion process. They vary in their body symmetry like are often the radial or bilateral kind of organization. The mode of feeding will be Parasitic or Heterotrophic. They have a systematic system which incorporates parts from mouth to rectum; the cardiovascular system could be a closed one with heart located ventrally.
Differences between vertebrates and invertebrates:

BASIS FOR COMPARISON	INVERTEBRATES	VERTEBRATES
Characteristics	No backbone.No cell walls.Reproduce sexually.No backbone. Heterotrophic (which depends on others for food) or Parasitic.	Presence of backbone.Cell walls present.Advanced nervous system.Well-developed internal skeleton.The outer covering of protective skin.
Size	Small and slow moving.	Vary in size from big too small.
Body Symmetry	Radial or bilateral	Bilateral
Body structure	Simple and unorganised nervous system.	Complex and highly specified organs and their functions.
Layers of skin	They have only one layer of skin.	Two layers of skin
Type of Eyes	Compound eyes are present and which are not outgrowth of the brain.	No compound eyes found and eyes are the outgrowth of the brain.
Presence	98% of animal species are invertebrates.	2% of the animal species are vertebrates
Examples	Insects, roundworms, tapeworms, Sponges, Annelids.	Humans, elephants, birds, snakes, etc.

 Note:
> The most remarkable difference between Invertebrates and Vertebrates is the presence of backbone, skull (outer covering of a brain) which is completely absent in Invertebrates and is well developed and proper functional in Vertebrates.
> Other features like the Nervous system, Respiratory system, Digestive system, Gastrointestinal tract and the Circulatory system is not so well developed and organized in Invertebrates as compared to Vertebrates.
> The body structure of Invertebrates is simple, with symmetry like radial or bilateral; Vertebrates have complex and organized body structure with only bilateral body symmetry.
Both types of animals are necessary for nature as they are directly or indirectly dependent on each other for their survival.