5General Characteristics Bilateral SymmetryProtostomesCoelomatesJointed appendagesExoskeleton of ChitinAll must “molt”All exhibit a form ofMetamorphosisBilaterally symmetrical
6All have three main body sections… a Head, a Thorax and an Abdomen
7HEAD antennae compound eyes head mouthparts The first body region is the head. Insect heads can behighly variable, but most possess eyes, antennae and mouthparts.headmouthparts
8Antennae are used by insects as major sensory beetlebutterflyflyanttermiteJune beetleAntennae are used by insects as major sensorydevices, especially for smell, and can be adaptive for the insect in many ways.
9Insect mouthparts are also highly modified for the Two Examples of Mouthpartschewingpiercing/suckingInsect mouthparts are also highly modified for theinsect. Chewing, biting, or sucking, are a few examples. Mouthparts of an immature insect may differ from those of the same insect in its adult stage.
10Thorax Picture of bodyparts The middle body region is called the thorax and is composed of three fused segments. All legs and wings are located on the thorax.Thorax
11The last body region is called the abdomen The last body region is called the abdomen. It is composed of many segments connected by flexible sections allowing it great movement.Abdomen
12Classification Class Insecta - Insects (6 legs) Class Arachnida – Spiders (8 legs)Class Crustacea – Crabs, etc..Members are distinguished for having… ^
13Reproduction Most are separate sexes. Fertilization is internal. Generally sexual, although some can reproduce parthenogenically.(reproduction without fertilization)Sex determination can be altered by a number of things.Some Arthropods develop through incomplete metamorphosis, some through complete metamorphosis.Sex determination can be altered by things such as:Environmentage of femalephotoperiodsize of host for parasitic arthropodsnumber of matings
14Incomplete Metamorphosis (immature forms are often called nymphs) Nymphs resemble the adult in form except for being smaller and lacking fully developed wings and sexual organs. Life Cycle: Egg --> nymph --> adult
15Complete metamorphosis Immature forms are called larvae (larva, singular). The pupal stage is a transition stage, when the larva is transformed to the adult. Pupa molts to the adult form. Life Cycle: Egg --> larva --> pupa --> adult
16Circulation Open Circulatory System Simple, one-chambered heart pumps blood through vessels into sinuses (chambers) and into the tissues…..blood returns to the heart through valved openings
17Open Blood SystemThe circulatory system is not composed of a central heart, veins and arteries which circulate blood cells and transport oxygen. The insect circulatory system is a simple tube (heart) down the back which is open at both ends and slowly pulses body fluids and nutrients from the rear of the insect to the head.
18Digestive System of an Insect intestineThe digestive system is a tube that opens at the mouth and empties at the tail end of the insect. It is divided into three parts called the foregut, midgut, and hind gut. In some insects such as the honey bee, the foregut acts as a crop to carry or hold liquids which can be regurgitated later.
19Digestive System Mouth – opening to the digestive system Pharynx – common duct for air and foodEsophagus – connects mouth to cropCrop – stores foodGizzard – grinds foodGastric Caeca – releases digestive enzymesVentriculus – stores foodPyloric Valve – regulates flow of foodIntestine – absorbs food into blood systemRectum – stores feces before dischargeAnus – opening out of the digestive system
20RespirationSome arthropods exchange gases through their “Body Surface”.Some arthropods exchange gases through Trachea “air ducts”.Some arthropods exchange gases through “Book Lungs”.Some arthropods exchange gases through “Book Gills”.
21The respiratory system is composed of air sacs and tubes called tracheae. Air enters the tubes through a series of openings called spiracles found along the sides of the body. The largest spiracles are usually found on the thorax where greater musculature from wings and legs require more oxygen. There are no spiracles on the head.
22Excretion in Insects Nitrogenous wastes are expelled as Uric Acid Crystals Mineral salts and Uric acid accumulates in the Malphigian Tubules and then transported to the intestines to be expelled through the anus
23Nervous System two lobed brain nerve bundles (ganglia) Insects have a less centralized nervous system than humans. The nerve chord runs along the ventral or bottom of an insect. The brain is divided into two main parts. The largest lobes control important areas such as the eyes, antennae, and mouthparts. Other major concentrations of nerve bundles called ganglia occur along the nerve chord and usually control those body functions closest to it.two lobed brainnerve bundles (ganglia)
24Complex Muscular System LocomotionJointed AppendagesComplex Muscular System
25Locomotion: Well Developed Muscle System with an Exoskeleton of Chitin