300802 Lecture Notes - Lecture 9: Arthropod Leg, Yolk Sac, Pulmonary Vein
Document Summary
Platyzoa (flat animal: platyhelminthes, bilateral symmetry, dorsoventrally flattened body, tripoblasty, acoelmate no body cavity. Incomplete gut: asexual reproduction by fission/budding and sexual, turbellaria free living, ciliated flatworms. Cercomeromorpha (tapeworm: cestoda intestinal parasites, scolex (attachment/hooks/suckers), neck, proglottis. Nematodes: roundworms, eelworms (fast moving ones in petri dish of prac, free-living parasite, predators of protists, small animals, have a thick collagen cuticle, bilateral symmetry, tripoblasty, psuedocoelomate, unsegmented, longitudinal muscles only, no respiratory or circulatory system. Arthropoda: 4 major groups, chelicerates, arachnids, sea spiders, horseshoe crabs, mouthparts are pincers or fangs (most anterior appendages, 4 pairs of legs, 2 body regions, araneae spiders. Predators, web forming, hunting, have poison glands: acari mites and ticks. Predators, cephalothorax and abdomen fused: crustaceans, crabs, lobsters, pill bugs, mouthparts are mandibles, appendages are biramous (two branched, head has 2 pairs of antennae, varied number of legs, gas exchange through gills or across cuticle, hexapods. Internal fertilization: apoda, caecilians, burrowing, legless, small eyes.
