The main difference between Insect and Animal is that the Insect is a class of invertebrates and Animal is a kingdom of multicellular eukaryotic organisms.
Insects or Insecta (from Latin insectum) are hexapod invertebrates and the largest group within the arthropod phylum. Definitions and circumscriptions vary; usually, insects comprise a class within the Arthropoda. As used here, the term Insecta is synonymous with Ectognatha. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. Insects are the most diverse group of animals; they include more than a million described species and represent more than half of all known living organisms. The total number of extant species is estimated at between six and ten million; potentially over 90% of the animal life forms on Earth are insects. Insects may be found in nearly all environments, although only a small number of species reside in the oceans, which are dominated by another arthropod group, crustaceans.
Nearly all insects hatch from eggs. Insect growth is constrained by the inelastic exoskeleton and development involves a series of molts. The immature stages often differ from the adults in structure, habit and habitat, and can include a passive pupal stage in those groups that undergo four-stage metamorphosis. Insects that undergo three-stage metamorphosis lack a pupal stage and adults develop through a series of nymphal stages. The higher level relationship of the insects is unclear. Fossilized insects of enormous size have been found from the Paleozoic Era, including giant dragonflies with wingspans of 55 to 70 cm (22 to 28 in). The most diverse insect groups appear to have coevolved with flowering plants.
Adult insects typically move about by walking, flying, or sometimes swimming. As it allows for rapid yet stable movement, many insects adopt a tripedal gait in which they walk with their legs touching the ground in alternating triangles, composed of the front & rear on one side with the middle on the other side. Insects are the only invertebrates to have evolved flight, and all flying insects derive from one common ancestor. Many insects spend at least part of their lives under water, with larval adaptations that include gills, and some adult insects are aquatic and have adaptations for swimming. Some species, such as water striders, are capable of walking on the surface of water. Insects are mostly solitary, but some, such as certain bees, ants and termites, are social and live in large, well-organized colonies. Some insects, such as earwigs, show maternal care, guarding their eggs and young. Insects can communicate with each other in a variety of ways. Male moths can sense the pheromones of female moths over great distances. Other species communicate with sounds: crickets stridulate, or rub their wings together, to attract a mate and repel other males. Lampyrid beetles communicate with light.
Humans regard certain insects as pests, and attempt to control them using insecticides, and a host of other techniques. Some insects damage crops by feeding on sap, leaves, fruits, or wood. Some species are parasitic, and may vector diseases. Some insects perform complex ecological roles; blow-flies, for example, help consume carrion but also spread diseases. Insect pollinators are essential to the life cycle of many flowering plant species on which most organisms, including humans, are at least partly dependent; without them, the terrestrial portion of the biosphere would be devastated. Many insects are considered ecologically beneficial as predators and a few provide direct economic benefit. Silkworms produce silk and honey bees produce honey and both have been domesticated by humans. Insects are consumed as food in 80% of the world’s nations, by people in roughly 3000 ethnic groups. Human activities also have effects on insect biodiversity.
Animals are multicellular eukaryotic organisms that form the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 millionths of a metre to 33.6 metres (110 ft) and have complex interactions with each other and their environments, forming intricate food webs. The category includes humans, but in colloquial use the term animal often refers only to non-human animals. The study of non-human animals is known as zoology.
Most living animal species are in the Bilateria, a clade whose members have a bilaterally symmetric body plan. The Bilateria include the protostomes—in which many groups of invertebrates are found, such as nematodes, arthropods, and molluscs—and the deuterostomes, containing the echinoderms and chordates (including the vertebrates). Life forms interpreted as early animals were present in the Ediacaran biota of the late Precambrian. Many modern animal phyla became clearly established in the fossil record as marine species during the Cambrian explosion which began around 542 million years ago. 6,331 groups of genes common to all living animals have been identified; these may have arisen from a single common ancestor that lived 650 million years ago.
Aristotle divided animals into those with blood and those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa (now synonymous with Animalia) and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between animal taxa.
Humans make use of many other animal species for food, including meat, milk, and eggs; for materials, such as leather and wool; as pets; and as working animals for power and transport. Dogs have been used in hunting, while many terrestrial and aquatic animals are hunted for sport. Non-human animals have appeared in art from the earliest times and are featured in mythology and religion.
An arthropod in the class Insecta, characterized by six legs, up to four wings, and a chitinous exoskeleton.
“Our shed has several insect infestions, including ants, yellowjackets, and wasps.”
Any small arthropod similar to an insect including spiders, centipedes, millipedes, etc
“The swamp is swarming with every sort of insect.”
A contemptible or powerless person.
“The manager’s assistant was the worst sort of insect.”
In scientific usage, a multicellular organism that is usually mobile, whose cells are not encased in a rigid cell wall (distinguishing it from plants and fungi) and which derives energy solely from the consumption of other organisms (distinguishing it from plants).
“A cat is an animal, not a plant. Humans are also animals, under the scientific definition, as we are not plants.”
In non-scientific usage, any member of the kingdom Animalia other than a human.
In non-scientific usage, any land-living vertebrate (i.e. not fishes, insects, etc.).
A person who behaves wildly; a bestial, brutal, brutish, cruel, or inhuman person.
“My students are animals.”
A person of a particular type.
“He’s a political animal.”
“a whole different animal”
Of or relating to animals.
Raw, base, unhindered by social codes.
Pertaining to the spirit or soul; relating to sensation or innervation.
a small arthropod animal that has six legs and generally one or two pairs of wings
any small invertebrate animal such as a spider or tick.
a living organism that feeds on organic matter, typically having specialized sense organs and nervous system and able to respond rapidly to stimuli
“wild animals adapt badly to a caged life”
“humans are the only animals who weep”
an animal as opposed to a human being
“are humans superior to animals, or just different?”
a mammal, as opposed to a bird, reptile, fish, or insect
“the snowfall seemed to have chased all birds, animals, and men indoors”
a person without human attributes or civilizing influences, especially someone who is very cruel, violent, or repulsive
“those men have to be animals—what they did to that boy was savage”
a particular type of person or thing
“property development was a different animal altogether”
“I am a political animal”
relating to or characteristic of animals
“the evolution of animal life”
of animals as distinct from plants
“tissues of animal and vegetable protein”
characteristic of the physical and instinctive needs of animals; of the flesh rather than the spirit or intellect
“a crude surrender to animal lust”
relating to or denoting the pole or extremity of an embryo that contains the more active cytoplasm in the early stages of development.