Ecdysozoans

Question 1

Describe 3 features of Ecdysozoans?

Answer 1

Eumetazoans, Bilaterians, Triploblastic.

Question 2

Define protostome?

Answer 2

Mouth develops first, the embryonic blastopore becomes the mouth.

Question 3

What two major traits do protostomes exhibit?

Answer 3

An anterior brain that surrounds the entrance to the digestive tract and a ventral nervous system consisting of paired or fused longitudinal nerve cords.

Question 4

List two key features of Ecdysozoans?

Answer 4

Have external skeletons secreted by an underlying epidermis and grow by moulting.

Question 5

What key trait do arthropods show?

Answer 5

Reduction in metamerism called heteronomous metamery.

Question 6

How is a scorpion specialised?

Answer 6

Abdominal segments are modified for digestion and reproduction, tail segments are modified for hunting and defence, anterior segments have fused and bear appendages for locomotion and feeding.

Question 7

What key molecule allowed arthropods to become successful?

Answer 7

Chiton

Question 8

List examples or extant segmented animals with unjointed legs?

Answer 8

Velvet worm, Tardigrades

Question 9

What elements do arthropod body plans exhibit?

Answer 9

Segmentation already arisen in annelids, muscles attached to inner surfaces of an external skeleton, limbs can aid movement which leads to success, jointed legs, wings.

Question 10

What is the Malpighian Tubule?

Answer 10

Kidney

Question 11

What element of the internal body plan have arthropods lost?

Answer 11

The ancestral coelom, their internal cavity has become a haemocoel; fluid from an open circulatory system bathes the internal cavities.

Question 12

What class do the early arthropods belong to are what characteristics do they display?

Answer 12

Trilobita, first jointed appendages, heavy exoskeletons better for deep in the ocean.

Question 13

Describe the elements of arthropod exoskeletons?

Answer 13

Thickened layers of waterproof chitin, restricts both movement and gas exchange, animals must have extensions of the body that can be manipulated by muscles.

Question 14

Why were aquatic arthropods able to invade terrestrial environments?

Answer 14

Due to the evolution of supportive and waterproof chitin.

Question 15

What belongs to the sub-plum Myriapoda?

Answer 15

Chilopoda - Centipedes and Diplopoda - Millipedes

Question 16

What differs between a centipede and a millipede?

Answer 16

Centipedes have one pair of legs per segment whereas millipedes have two adjacent segments fused so that each fused segment has two pairs of legs.

Question 17

What 3 major clades belong to the sub-phylum Chelicerata?

Answer 17

Pycogonids (sea spiders), Horse shoe crabs and Arachnids.

Question 18

What characteristics are common of Chelicerata?

Answer 18

2 regions, anterior bears two. appendages modified into mouthparts, four pairs of walking legs, prosoma, chelicerae and pedipalps (mouthparts) and Opisthosoma (abdomen)

Question 19

What belongs to the class Arachnida?

Answer 19

Spiders, scorpions, mites and ticks.

Question 20

What is special about spiders?

Answer 20

Spider spinnerets are organs from which web silk is extruded, pulling and pressure by the spider rearranges the liquid silk polymer molecules into a solid but flexible thread.

Question 21

What belong to the sub-phylum Hexapoda?

Answer 21

Collembola (Springtails), Dipluran (bristletails), Proturans (wingless relatives of insects) and Insecta.

Question 22

What class is the dominant terrestrial arthropod?

Answer 22

Insecta

Question 23

Describe the three basic regions of the insect body plan?

Answer 23

A head with a single pair of antennae attached.
A thorax with three pairs of legs attached.
An abdomen with no appendages.

Question 24

What are the two orders of the Class Crustacea?

Answer 24

Decapoda (Lobsters, crayfish, crabs, shrimp)

Isopoda (Sowbugs, pillbug, roll-polys)