Just a quick and dirty discussion of the insects, since this seems like an appropriate place to do it and you may find it useful.
Living things are described based on different traits they possess. Morphological, developmental, genetic, ecological and behavioral differences have all been used to describe, differentiate and sort living things into various categories to show relationships. These are the traditional kingdom, phylum, class, order, genus, species structure most of us learned about in school.
Insects are a class of animal in the phylum Arthropoda. Not to belabor or belittle what we all know, they have three body regions, six legs and are invertebrates. The class is represented by about 30 orders which are the groups we are most commonly familiar with. Springtails, firebrats/silverfish, bristle tails and a few other groups are more adaptively primitive and are sometimes grouped as a sister subclass to the the other orders. The orders we are often most familiar with by common name (with exceptions) are cockroaches, termites, grasshopper/crickets, mantids, walking sticks, mayflies, stoneflies, book lice, leaf hoppers/tree hoppers, true bugs, lice, beetles, flies, Neuroptera (scorpion flies, Dobson flies, hangingflies), caddisflies, butterflies/moths, flies, wasps/bees and fleas. There are a few other, smaller orders I have not mentioned, but those mentioned represent the bulk of the fauna. They are the most numerous (over 1,000,000 million descried species) known group of animals on the planet. Beetles are the most species rich group of living things and nearly 350,000 species are known. Roughly, every third animal you encounter will be a beetle. Like
@Sgt. Pepper the beetles are my favorite group. Though her favored version differs from mine.
Insects exploit every habitat we know of except the marine aquatic habitat that is the domain of other, sometimes related invertebrates. They are likely the first winged, flying thing to exist and probably the first noisy living things. They come in exotic shapes, colors and variations. Their morphology, biology and habits are endlessly fascinating and wonderous. I was bitten by a love of these animals as a child and have never recovered.