What are insects? What are the main characteristics of insects?

Insects are a type of invertebrates. They constitute the largest group in the biological world. There are currently more than one million known species of insects, making them the most diverse organisms after the plant kingdom. The following are the main characteristics of insects:

Exoskeleton:

The body of an insect is made up of an exoskeleton, a hard-shell exoskeleton called a shell, which provides body support, protects internal organs, and provides attachment points for appendage muscles.

Segments and appendages:

The body of an insect is usually divided into three parts: head, thorax and abdomen, with obvious segmentation. Their appendages usually appear as six legs on the thorax and abdomen, and the head often carries antennae and compound eyes.

Compound eyes and single eyes:

Most insects have compound eyes on their heads, which are organs that focus external light into images. In addition, some insects have one or more pairs of single eyes that can also perceive light.

wing:

Most insects have wings, which enable them to fly through the air. But not all insects can fly. Some types of insects do not have wings, or only some types of adults have wings.

Valve system:

Insects breathe through a system of valves on their body surface, which allows air to enter directly into the insect's body without passing through the lungs or other internal organs.

Oviparous:

Most insects are laid as eggs and, after the eggs hatch, go through the life cycle stages of nymph, larva, pupa and adult.

change:

Most insects have a complete metamorphosis life cycle, including the four stages of egg, larvae, pupa and adult, which is considered to be an important feature that distinguishes insects from other invertebrates.

animal tags：