Insects+and+Relatives

 Insects and their Relatives

Insects are like arthropods because they have a segmented body, an exoskeleton, and jointed appendages. They have a body divided into three parts: the head, Thorax, and abdomen. Three pairs of legs are attached to the thorax. Insects, centipedes, and millipedes are all Uniramians which is a group that contain more species than all other groups of animals alive today. Uniramians have jaws, one pair of antennae, and unbranched appendages. Despite having unbranched appendages they have a widely varying forms and life styles. Centipedes and millipedes have long worm like structures composed of mainly leg bearing segments. Centipedes have form a few to more than 100 pairs of legs, depending on the species. They are carnivores whose mouths include a pair of v enomous claws. Centipedes usually live beneath rocks or in the soil, theses centipedes loose water fast because of their spiracles cannot close, therefore they cannot live in most humid areas. Millipedes also have a highly segmented body but each millipede can bear two legs instead of one. These legs develop from the fusion of two segments in the millipede embryo. They live near dead logs and under rocks because they feed on dead plants. They are very timid and if threatened they will roll up to a ball to protect their softer undersides. Some of them can release toxic chemicals when they feel in danger. Insects use a multitude of sense organs to respond to stimuli. They have compound eyes that are made up of many lenses to detect change in movement and changes of color. They see less detailed than us but they detect movement really fast therefore its hard to swat a fly. The insects also have chemical receptors for taste and smell on their mouth parts. They also have it on their antenna and legs so if they step on water it knows if it is made up of salt or if it contains sugar. They also have sensory hairs that detect movement when they fly or in water. Also they have very developed ears to hear sounds far above the human range. Insects have three pairs of appendages that are used as mouthparts, including a pair of mandibles. They help the insect feed on stuff, by producing silva helping them breakdown food. These chemicals can help bees turn nectar into honey. Insects have three pairs of legs which depending on its species can be used to help for walking, jumping or capturing its prey. They have hooks that are used for grasping and defense. Also many insects can fly, they have two pairs of wings that are made up Chitin which is the same substance that makes up its exoskeleton. These insects fly depending on their species cause some fly slow like butterflies or fast like flies or bees that can change their position and speed really fast. A dragonfly can also reach speeds as fast as 50 kilometers an hour! These insects grow and developed through a cycle called metamorphosis. It can change its shape and form these insects either go through incomplete or complete metamorphosis. An example of incomplete metamorphosis is when nymphs lack functional sexual organs and wings. They can eventually acquire adult form through time. Complete metamorphosis insects hatch nothing like their parents and feed completely different ways than adult insects. The larva forms into a pupa where the body is completely different and when it emerges it looks like another animal. These animals can interact by releasing chemical that are called Pheromones which are specific chemical messengers that effect behavior or the development of other individuals of the same species.