Phylum Arthropoda

 

Arthropods have jointed appendages, there exoskeletons is made up of chitin and it protects,anchors, muscles and prevents drying out. since there exoskelton is hard and dosnt expange the need to molt for animal to grow. insects, arachinids, centepides and millipedes are all adapted to terrestrail life. they have a well developed nervous sytem and a brain with a solid ventral nerve cord.
CRUSTACEA- have a calcified exoskeleton this includes lobsters, crabs  and barnacles. they have compound eyes, 2 pairs of antennae and 3 mouthparts. stomach grinds food and filters it before absorbing it. coelom is reduced to cavity around reproductive system. sexes are separate
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INSECTS-THREE BODY REGIONS, HEAD THORAX AND ABDOMEN.head has sensory antennae, eyes, and mouthparts. thorax has three pairs of legs, adults may have a pair of wings or 2. lastly abdomen contains internal organs and exoskeleton is lighter with less chitin than others.

Plylum Mollusca

Mollusks, are soft bodied animals, there are about 110,000 species including clams, squids, snails. octopuses, and oysters. three main parts of mollusks are the VISCERAL MASS (Soft portion that contains internal organs) the FOOT (muscle used for locomotion) and the MANTLE (muscular covering). many show cephalization, have eyes and sense organs.
GASTROPODS- snails, conches and neudibroche. have ventrally flattened foot and move by contracting. have a coiled shell containing visceral mass.
CEPHALOPODS- Octopuses and squids have feet that evolved to tentacles as well as powerful beaks and radula (toothy tongue), and a brain fused from ganglia.
BIVALVES- clams, scallops and oysters. bivalve is referring to 2 shells made of CO2. their gills function in gas exchange as well as their blood flows through an open circulatory system. clams lack cephalization, nervous system made of 3 pairs of ganglia, they are also filter feeders where water enters the incurrent siphon and is passed out the anus through the excurrent siphon.
sexes are separate.