Slides 27

Question 1

ecdysozoans

Answer 1

animals with a cuticle (tough external coat), cuticle is shed during ecdysis or molting, arthropods is largest phyla

Question 2

arthropods

Answer 2

all habitats, more than million species,

Question 3

arthropod origins

Answer 3

body plan: segmented body, hard exoskeleton, jointed appendages, Cambrian explosion, old showed little variation

Question 4

arthropod evolution

Answer 4

body regions specialized for deeding, walking, or swimming; diverse body plan due to changes in sequence of regulation of existing Hox genes

Question 5

arthropod characteristics

Answer 5

appendages have been modified for walking, feeding, sensory reception, reproduction, defense; jointed and come in pairs

Question 6

arthropod exoskeleton

Answer 6

cuticle covers entire body and is made of layers of protein and polysaccharide chitin; separated by function; protection and points of attachment; helps retain water, protects internal organs, supports body with gravity

Question 7

arthropod advancements

Answer 7

eyes, olfactory receptors, antennae (more complex sensory features); open circulatory system uses heart to pump hemolymph into hemocoel cavity

Question 8

anthropod diversity

Answer 8

main 3 lineages: chelicerates, myriapods, pancrustaceans

Question 9

chelicerates

Answer 9

clawlike feeding appendages called chelicerae; eurypterids earliest members; sea spiders and horseshoe crabs

Question 10

myriapods

Answer 10

millipedes, centipedes; terrestrial; pair of antennae, 3 pairs of appendages modified as mouthparts

Question 11

pancrustaceans

Answer 11

insects more related; insects and crustaceans

Question 12

crustaceans

Answer 12

crabs, lobsters, shrimps; marine, freshwater, terrestrial habitats; have highly specialized appendages: anterior-most form two pairs of antennae, 3 or more pairs are modified as mouthparts, walking legs are located on thorax, swimming appendages are located on the tail

Question 13

insects

Answer 13

hexapoda (insects); more than 30 orders, early diverging wingless insects; rapid diversification following evolution of flight as extension of the cuticle

Question 14

echinodermata

Answer 14

starfish, echinoderms; slow-moving or sessile marine animals; most adults appear to have radial symmetry but not true, larvae have bilateral symmetry

Question 15

echinodermata body plan

Answer 15

coelom and endoskeleton of hard calcareous plates; water vascular system which is a network of hydraulic canals branches into tube feet that function in locomotion and feeding; separate sexes and external fertilization

Question 16

chordata

Answer 16

contains urochordata and cephalochordata; 4 distinct features at some point in development: notochord, dorsal hollow nerve cord, phaaryngeal slits, post-anal tail; never develop bony backbone