chapter 36: arthropods

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phylum arthropoda

arthropods- members of the phylum arthropoda

true coelom

segmented animals

wings

respiratory and excretory structures

bear jointed extensions called appendages

has an exoskeleton

chitin- tough polysaccharide that makes up the middle layer of the exoskeleton

high amount of cephalization

compound eyes- eyes made only out of light detectors with own lenses

-know the sensitive structures of the eye

rhabdom

ommatidia

facet

cyrstalline cone

pigment cells

visual cells

optic nerve fibers-

all arthropods have an open circulatory system

molting- arthropods goes through cycles of molting to be able to grow; the process of shedding an exoskeleton or outer layer

begins at the tissues that gradually swell

when pressure is so strong a hormone is triggered to secrete enzymes that will digest the inner layer of the exoskeleton

new exoskeleton stretches to fit the animal and takes hours to days to become hard like the old one

*biologists believe arthropods came from a common ancestor. they are similar to...

-triloites- many body segments and one pair of appendages on each segment

tagma- some segments that are fused into this larger structure; specialized for either feeding, movment, or reproduction

two major different mouthparts

mandible- jaw like

chelicerae- pincer like

5 main subphyla

Trilobita

Crustacea

Chelicerata

Myriapoda

Hexapoda

types of arthropods

spiders, scorpions

insects

centipedes and millipedes

crustaceans