17

Question 1

Ecdysozoans?

Answer 1

One of the Protostomes two major clades

•nematodes and arthropods

Synapomorphies: shedding of the cuticle and exoskeletons

Question 2

Nematodes?

Answer 2

Ecdysozoan, roundworms.

They flow through gut. Their interiors are pseudocoelomate and unsegmented (body divided into different parts)

Question 3

The most important model organism in Ecdysozoans?

Answer 3

C. elegans?

Question 4

Why are c. Elegans so important as a model organism?

Answer 4

Few number of cells, simplicity in nervous system, and transparent, quick reproduction, and exhibit behaviours. Useful for neurological research.

Question 5

Arthropods are sister to?

Answer 5

Nematodes

Question 6

Arthropods?

Answer 6

They have body plans formed from segments that can remain separate or fuse.

Synapomorphies: Bent appendages

Flexibility and modularization of these segments and appendages that has allowed for independent development and evolution of regions and appenda in different lineages.

Question 7

Chelicerates?

Answer 7

•Chelicerates (spiders and scorpions): they have chelicerae, a pair of appendages on the head used as mouthparts to grab but not chew prey

Question 8

Myriopods?

Answer 8

Millipedes and centipedes. Millipedes have two pairs of legs for every body segment and vegetarians. Centipedes have one pair of legs per body segment and carnivores

Question 9

Trilobites?

Answer 9

One of the most successful animals during their period, went extinct during the Permian mass extinction. The first animals to clearly see

Question 10

Pancrustaceans?

Answer 10

A clade containing crustacean and insecta.

Question 11

Arthropods contain what major clades? 4•

Answer 11

•Trilobites
•Chelicerates
•Myriapods
•Pancrustaceans

Question 12

First animals to fly about and what were?

Answer 12

350 million years ago, insects

Question 13

How many years ago did different organisms evolved to fly from now? 3•

Answer 13

•Pterosaurs: 200 Mya
•Feathered dinosaurs and birds: 165 Mya
•Mammals: 50 Mya

Question 14

Are insect flight wings modified walking limbs?

Answer 14

No, they are actually completely new appendages.

Question 15

Deuterostomes?

Answer 15

One of Bilateria two major clades

Question 16

In Deuterostomes vs protostomes, how do the cephalized central nervous system differ?

Answer 16

Cephalized central nervous system runs through the dorsal (back) part of the body in Deuterostomes while in the ventral (front) part of the body in protostomes.

Question 17

Outgroup of Deuterostomes?

Answer 17

Echinoderms

Question 18

Echinoderms?

Answer 18

Include starfish, brittle stars, crinoids, sea urchins, and sea cucumbers. They are sister to Chordates but lack a head. They have bilaterally symmetrical larvae, but as adults, they are radially symmetric.

Synapomorphy: pentaradial symmetry, 5-part symmetry and water vascular system.

Question 19

Water vascular system?

Answer 19

Hydraulic system to move around and feed. They have tiny muscles to move water into the tube feet to move water along.

Question 20

Deuterostomes characteristics?

Answer 20

Starfish: predators
•Sea urchins: grazers (no arms) special structure:Aristotle’s lantern
•Brittle stars: scavengers
•Crinoids: attached to stalk as juveniles, free swimming as adults
•Sea cucumbers: scavengers, secondarily bilateral.

Synapomorphies: radial symmetry as adults, water vascular system with tube feet.