Biodiversity 6

Question 1

Bilateria: Deeuterostomes: Echinoderms

Answer 1

Taxonomic relationships:
- echinoderms are sister group to chordates. They are within bilateria and deuterostomes

Synapomorphies:
Radial symmetry as adults, water vascular system with tube feet
Starfish: predators
Sea urchins: grazers, no arms special structure, artisotle lantern
Brittle stars: scavengers
Crinoids: attacjed to stalk as juveniles, free swimming as adults
Sea cucumbers: scavengers, secondarily bilateral

Question 2

Nematodes

Answer 2

caenorhabditis elegans

Question 3

Arthropods

Answer 3

• form segments that remain separate or fuse
• joined appendages
• flexibility of these segments

Question 4

Chelicerates

Answer 4

• spiders and scorpians
  Chelicerae: pair of appendages on the head that are used as mouthparts to grab but not chew prey

Question 5

Myriapods: milipedes and centipedes

Answer 5

Mili- two pairs of legs per body segments
Centi- one par of legs per body segment

Question 6

Trilobites are within what clade?

Answer 6

ecdysozoa

Question 7

Crustacea

Answer 7

• paraphyletic clade; united with insects within the clade pancrustacea

Question 8

Insects

Answer 8

• have three part body plan and six pairs of walking legs

Question 9

What does the echinoderms include

Answer 9

starfish, brittle stars, crinoids, sea urchins, and sea cucumbers
- they have bilaterally symmetrical larvae