ARTHROPODS Insects Shrimp Centipedes Lobsters Millipedes.

ARTHROPODS

Insects• Shrimp

•Centipedes

•Lobsters

Millipedes

Arthropods are the most successful animals!

•They are found in many environments.

•They can ADAPT to many environments.

Phylum: Arthropoda

Characteristics:• Arthropoda means jointed foot• Appendages grow from the body• The body is divided into three

segments:– Head ~ 1st part, contains the sense organs– Thorax ~ middle, joins head & abdomen

walking legs are attached here

-Abdomen ~3rd part, reproductive & digestive organs are found here

All arthropods have an external skeleton called the

exoskeleton.

The exoskeleton has several functions:

*covers

*supports

*protects

*prevents from drying out

Arthropods molt their exoskeleton.

Molting is a process of shedding the exoskeleton and replacing a new one in order to grow.

What problems do you see with this process?

Class ~ Crustacean

Types of Crustaceans

Crabs

Lobsters

Shrimp

• Pill bug

• Barnacles

• Water fleas

CharacteristicsCephalothorax- head & thorax fused togetherOne or two pairs of antennaeMandibles ~ jaws used for crushing foodFive pairs of legs:1st pair~ claws, catching food, protectionFour pairs of walking

Swimmerets ~ appendages on the abdomenMovementReproductionForce water over the gills for breathingRegenerate lost appendages

CRAYFISH~ A common crustaceanCRAYFISH~ A common crustacean

• Cephalothorax and abdomen• Two pairs of antennae

Shorter pair-Touch, taste, balance

Longer pairTouch, taste, smell

• Compound eyes ~ located at the end of the eye stalks

– Why is this an advantage?

Class ~ Insecta

Insects: Largest class of Arthropods

• Most successful animals: – reproduce in mass numbers – lives in many environments

Characteristics of Insects:

• 3 body parts: head, thorax, abdomen

• Mandible- specialized mouth part

• Antenna or feelers for touch or smell

• 1 or 2 pairs of wings

• Reproduction- sexual• Complete metamorphosis

• Incomplete metamorphosis

Grasshopper

• Most common insect

• Two types of eyes- simple & compound

• 3 pairs of legs:– 1st two pairs- walking– 3rd pair- jumping

Grasshopper (cont.)

• two pairs of wings

• spiracles- found on the abdomen for respiration/breathing

• Reproduction- sexual– Incomplete metamorphosis:

• Egg, nymph, adult

Metamorphosis

• A series of distinct changes in form through which an organism passes as it develops from an egg to an adult.

• Complete Metamorphosis (4 stages):– egg- larva–pupa-adult

• Incomplete (3 stages):– egg- nymph-adult

Class ~ Arachnid

Characteristics

• Two body parts:– Cephalothorax: head & thorax fused together– Abdomen

• no antennae

• four pairs of legs

• poison glands, stingers or fangs

• four pairs of simple eyes

Spider Chelicerae

Fangs, Chelicerae of Zebra Jumping SpiderSalticus scenicus

www.microscopix.co.uk/spiders/fangs/index.htm

Fangs and Chelicerae of Tarantula SpiderlingBrachypelma smithi(Mexican Red-Knee Tarantula)

SPIDERS

• A common arachnid• Eight compound eyes to sense light and darkness• Cannot chew food ~ inject poison into their prey

which paralyzes it and then turns the food into liquid

• Book lungs ~ series of flat, air filled plates used in respiration

• Spiracles~ openings in the abdomen that allow oxygen in and carbon dioxide out

Some arachnids are parasites!

• TICKS– Rocky Mountain Fever

– Lyme Disease

• MITES– Chiggers

– House dust mites

– Eyelash mites

Class: Centipede

• 1 pair of legs per body segment

• usually a flat body• 1 pair of antenna• feed on insects and

spiders• move fast

Class: Millipede

• 2 pairs of legs per body segment

• rounded body• 1 pair of antenna• feed organic matter-

leaves and wood• move slow

Arthropod Review

• How many classes of Arthropods?

• 5

• Name the classes

• Crustaceans• Insects• Arachnids• Centipedes• Millipedes