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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