1. Phylum Arthropoda

2. Honey bees - good or bad?
Are honey bees good or bad? They are good when
they pollinate and produce honey, but bad when they sting.

3. Termites - good or bad?
© Troy Bartlett
They are bad when they eat the wood in your house, but good when they break down dead and fallen trees.

4. Termites - good or bad?
© Troy Bartlett
They are bad when they eat the wood in your house, but good when they break down dead and fallen trees.

5. General Characteristics
Bilateral Symmetry
Protostomes
Coelomates
Jointed appendages
Exoskeleton of Chitin
All must “molt”
All exhibit a form of
Metamorphosis
Bilaterally symmetrical

6. All have three main body sections… a Head, a Thorax and an Abdomen

7. HEAD antennae compound eyes head mouthparts
The first body region is the head. Insect heads can be
highly variable, but most possess eyes, antennae and mouthparts.
head
mouthparts

8. Antennae are used by insects as major sensory
beetle
butterfly
fly
ant
termite
June beetle
Antennae are used by insects as major sensory
devices, especially for smell, and can be adaptive for the insect in many ways.

9. Insect mouthparts are also highly modified for the
Two Examples of Mouthparts
chewing
piercing/sucking
Insect mouthparts are also highly modified for the
insect. 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.

10. Thorax 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

11. The 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

12. Classification Class Insecta - Insects (6 legs)
Class Arachnida – Spiders (8 legs)
Class Crustacea – Crabs, etc..
Members are distinguished for having… ^

13. Reproduction 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:
Environment
age of female
photoperiod
size of host for parasitic arthropods
number of matings

14. Incomplete 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

15. Complete 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

16. Circulation 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

17. Open Blood System
The 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.

18. Digestive System of an Insect
intestine
The 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.

19. Digestive System Mouth – opening to the digestive system
Pharynx – common duct for air and food
Esophagus – connects mouth to crop
Crop – stores food
Gizzard – grinds food
Gastric Caeca – releases digestive enzymes
Ventriculus – stores food
Pyloric Valve – regulates flow of food
Intestine – absorbs food into blood system
Rectum – stores feces before discharge
Anus – opening out of the digestive system

20. Respiration
Some 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”.

21. The 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.

22. Excretion 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

23. Nervous 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 brain
nerve bundles (ganglia)

24. Complex Muscular System
Locomotion
Jointed Appendages
Complex Muscular System

25. Locomotion: Well Developed Muscle System with an Exoskeleton of Chitin

26. Must Molt ( shed) in order to grow.

27. Habitats
Live in most habitats
Earth
Sea
Sky

28. Some even help keep arthropod population in check
Importance to Environment
Pollination
Food for other animals
Some even help keep arthropod population in check

29. Effect on Man Good Bad Food, clothing medicines
protection from harmful organisms
Bad
devastating plagues
famines

30. The End