BIO2231 - Arthropoda III - Chelicerates and Myriapods

Question 1

<p><span>Subphylum Chelicerata</span></p>

<p><strong><span>What are the members?</span></strong></p>

<p>7 points.</p>

Answer 1

<ul> <li>Sea spiders</li> <li>Horseshoe crabs</li> <li>Arachnids</li> <ul> <li>Scorpions</li> <li>Harvestmen</li> <li>Spiders</li> <li>Mites & ticks</li> </ul></ul>

<p><span>_{BIO2231 8aa}</span></p>

Question 2

<p><span>Subphylum Chelicerata</span></p>

<p><strong><span>Body plan</span></strong></p>

<p>8 points.</p>

Answer 2

<ul> <li>Appendages - 6 pairs :</li> <ul> <li>1st pair = chelicerae</li> <li>2nd pair = pedipalps</li> <li>4 pairs = walking legs</li> </ul> <li>All limbs are uniramous</li> <li>No antennae</li> <li>Anterior segments fused form a prosoma</li> <li>Posterior segments fused form opisthoma</li></ul>

<p><span>_{BIO2231 8ab}</span></p>

Question 3

<p><span>Subphylum Chelicerata</span></p>

<p><strong><span>Circulatory system</span></strong></p>

<p>2 points.</p>

Answer 3

<ul><li>Open circulatory system </li><li>Well-developed heart pumps blood through arteries, which branch into smaller vessel which lead into sinuses</li></ul>

<p><span>_{BIO2231 8ac}</span></p>

Question 4

<p><span>Subphylum Chelicerata</span></p>

<p><strong><span>Digestive system</span></strong></p>

<p>2 points.</p>

Answer 4

<ul><li>A preoral cavity formed by chelicerate and pedipalps </li><li>Digestive ceca</li></ul>

<p><span>_{BIO2231 8ad}</span></p>

Question 5

<p><span>Subphylum Chelicerata</span></p>

<p><strong><span>Excretion system</span></strong></p>

Answer 5

<p><span>_{BIO2231 8ae}</span></p>

Question 6

<p><span>Subphylum Chelicerata</span></p>

<p><strong><span>Excretion system</span></strong></p>

Answer 6

<p><span>Malpighian tubules</span></p>

<p><span>_{BIO2231 8af}</span></p>

Question 7

<p><span>Subphylum Chelicerata</span></p>

<p><strong><span>Sensory</span></strong></p>

Answer 7

<div><strong>Aquatic</strong>: simple/ compound eyes, </div>

<div><strong>Terrestrial</strong>: several simple eyes or ocelli </div>

<div>Mechanoreceptors sensory hairs/bristles for touch/sound</div>

<p><span>_{BIO2231 8ag}</span></p>

Question 8

<p><span>Subphylum Chelicerata</span></p>

<p><strong><span>class Pycnogonida</span></strong></p>

<p>9 points.</p>

Answer 8

<ul><li>Very thin body </li><li>Long, thin legs (sometimes 5-6 prs rather then 4 common to chelicerates, oxygen diffusion) </li><li>Proboscis (feeding) </li><li>Reduced abdomen </li><li>2 pairs of simple eyes </li><li>Exclusively marine </li><li>Carnivores: feed on sessile, soft bodied organisms (eg cnidarians) </li><li>Ovigers </li><li>Gonopores</li></ul>

<p><span>_{BIO2231 8ah}</span></p>

Question 9

<p><span>Chelicerata: class Merostomata</span></p>

<p><strong><span>Subclass Xiphosurida</span></strong></p>

<p>6 points.</p>

Answer 9

<p><span>Horseshoe crabs</span></p>

<ul><li>Ancient: largely unchanged for 250 million y </li><li>Cephalothorax, abdomen and long telson </li><li>Compound and simple eyes </li><li>Mouth=gnathobases </li><li>Book gills </li><li>Omnivores</li></ul>

<p><span>_{BIO2231 8ai}</span></p>

Question 10

<p><strong><span>What is LAL (Limulus Amoebocyte Lysate)?</span></strong></p>

<p>5 points.</p>

Answer 10

<p><span>An aqueous extract of blood cells from the Atlantic horseshoe crab</span></p>

<ul> <li>Milking horseshoe crabs</li> <li>Hemolymph has amoebocytes</li> <li>Contain clotting factor (coagulogen)</li> <li>Reaction to bacterial endotoxins</li> <li>Gram-negative bacteria test</li></ul>

<div></div>

<div><strong>Blue colour due to hemocyanin</strong></div>

<p><span>_{BIO2231 8aj}</span></p>

Question 11

<p><span>Chelicerata: class Merostomata</span></p>

<p><strong><span>Subclass Eurypterida</span></strong></p>

Answer 11

<p><span>Sea Scorpions</span></p>

<div>Now extinct</div>

<p><span>_{BIO2231 8ak}</span></p>

Question 12

<p><span>Chelicerata: class Arachnida</span></p>

<p><strong><span>Order Acari</span></strong></p>

<p>5 points.</p>

Answer 12

<p><span>Mites and Ticks</span></p>

<ul> <li>Very diverse ecologies</li> <li>Apparent lack of tagmata (complete fusion of opisthoma and the prosoma)</li> <ul> <li>Gnathosoma (mouth and feeding parts) - chelicerae and pedipalpal coxae</li> <li>Idiosoma - rest of cephalothorax and abdomen</li> </ul> <li>Smaller ones have no respiratory organs</li></ul>

<p><span>_{BIO2231 8al}</span></p>

Question 13

<p><span>Chelicerata: class Arachnida</span></p>

<p><strong><span>Order Araneae</span></strong></p>

<p>10 points.</p>

Answer 13

<p><span>Spiders</span></p>

<ul> <li>All predators</li> <li>Clearly two tagmata</li> <ul> <li>prosoma (cephalothorax)</li> <li>opisthosoma (abdomen)</li> </ul> <li>Simple eyes</li> <li>Book lungs or trachae (some both)</li> <li>Complex behaviours</li> <ul> <li>Courting rituals </li> <li>Social spiders: live in colonies i.e huntsman </li> <li>Nuptial gifts</li> </ul></ul>

<p><span>_{BIO2231 8am}</span></p>

Question 14

<p><span>Chelicerata: class Arachnida - Order Araneae</span></p>

<p><strong><span>Mygalomorphae</span></strong></p>

Answer 14

<p><span>Fangs bite parallel to the body</span></p>

<div>Funnel Web, Trapdoors etc</div>

<p><span>_{BIO2231 8an}</span></p>

Question 15

<p><span>Chelicerata: class Arachnida - Order Araneae</span></p>

<p><strong><span>Araneomorphae</span></strong></p>

Answer 15

<p><span>Fangs bite at right angles to the body</span></p>

<div>Most common spiders</div>

<p><span>_{BIO2231 8ao}</span></p>

Question 16

<p><span>Chelicerata: class Arachnida</span></p>

<p><strong><span>Order Scorpiones</span></strong></p>

<p>9 points.</p>

Answer 16

<ul> <li>All predators</li> <li>Large chela (are not chelicera)</li> <li>Small chelicera</li> <li>Abdomen in two parts</li> <ul> <li>Preabdomen 7 segments</li> <li>Postabdomen 5 segments</li> </ul> <li>Sting: venom neurotoxin</li> <li>Viviparous</li> <li>Large median eyes, 2-5 pairs of small lateral eyes</li></ul>

<p><span>_{BIO2231 8ap}</span></p>

Question 17

<p><span>Chelicerata: class Arachnida</span></p>

<p><strong><span>Order Opiliones</span></strong></p>

<p>6 points.</p>

Answer 17

<p><span>Harvestmen</span></p>

<ul><li>Chelicerae fangs but no venom </li><li>Compact body prosoma and opisthosoma fused </li><li>One pair of eyes often on an eyemound </li><li>No stomach </li><li>Omnivores </li><li>No spinnerets</li></ul>

<p><span>_{BIO2231 8aq}</span></p>

Question 18

<p><strong><span>Subphylum Myriapoda</span></strong></p>

<p>8 points.</p>

Answer 18

<p><span>Myriapoda ≈ many footed</span></p>

<ul><li>Bodies elongate with many segments </li><li>2 body tagmata (head, trunk) </li><li>Most segments with a pair of appendages </li><li>Pair of antennae </li><li>Pair of simple eyes </li><li>Malpighian tubules </li><li>Trachea and spiracles </li><li>A pair of mandables present</li></ul>

<p><span>_{BIO2231 8ar}</span></p>

Question 19

<p><span>Subphylum Myriapoda</span></p>

<p><strong><span>Class Chilopoda</span></strong></p>

<p>4 points.</p>

Answer 19

<p><span>Centipedes</span></p>

<ul><li>One pair of legs per segment </li><li>Dorsoventrally flattened </li><li>Poisonous forcipules </li><li>Carnivorous</li></ul>

<p><span>_{BIO2231 8as}</span></p>

Question 20

<p><strong><span>Class Diplopoda</span></strong></p>

<p>4 points.</p>

Answer 20

<p><span>Millipedes</span></p>

<ul><li>Two pairs of legs per segment </li><li>Cylindrical body </li><li>Repel predators with poison </li><li>Herbivorous</li></ul>

<p><span>_{BIO2231 8at}</span></p>

Question 21

<p><strong><span>Subphylum Hexapoda</span></strong></p>

Answer 21

<ul><li>Big biological success story!!</li><li>1.1 million described species</li><li>Estimates range to 30 million species</li><li>Some groups extremely diverse e.g. Coleopterans (beetles)</li></ul>

<p><span>_{BIO2231 8au}</span></p>

Question 22

<p><span>Subphylum Hexapoda</span></p>

<p><strong><span>Body plan</span></strong></p>

<p>8 points.</p>

Answer 22

<ul> <li>3 body tagmata (divisions)</li> <ul> <li>Head</li> <li>Thorax</li> <li>Abdomen</li> </ul> <li>3 pairs of legs (uniramous)</li> <li>2 pairs of wings</li> <li>Malipighian tubules</li> <li>Loss of second antennae</li></ul>

<p><span>_{BIO2231 8av}</span></p>

Question 23

<p><span>Subphylum Hexapoda</span></p>

<p><strong><span>Class Entognatha</span></strong></p>

<p>3 points.</p>

Answer 23

<ul><li>Order Collembola: springtails </li><li>Six abdominal segments </li><li>Maxillae and mandibles concealed</li></ul>

<p><span>_{BIO2231 8aw}</span></p>

Question 24

<p><span>Subphylum Hexapoda - Class Insecta</span></p>

<p><strong><span>Subclass Apterygota</span></strong></p>

<p>2 points.</p>

Answer 24

<p><span>Order Thysanura: silverfish/bristletails</span></p>

<ul><li>No wings </li><li>Little to no metamorphosis</li></ul>

<p><span>_{BIO2231 8ax}</span></p>

Question 25

<p><span>Subphylum Hexapoda - Class Insecta</span></p>

<p><strong><span>Subclass Pterygota</span></strong></p>

<p>7 points.</p>

Answer 25

<ul> <li>Most familiar insects</li> <li>Two pairs of wings in most adults</li> <li>Grouped based on wing function</li> <li><strong>Infraclass Paleoptera </strong>= oldest group</li> <ul> <li>Mayflies (Order Ephemeroptera)</li> <li>Dragonflies (Order Odonata)</li> </ul> <li><strong>Infraclass Neoptera</strong></li></ul>

<div></div>

<div>Fossil Insect with wings Including a "winglet" on the first segment of the thorax (300 MYA)</div>

<p><span>_{BIO2231 8ay}</span></p>