Lab 7

Question 1

What are Nematodes

Answer 1

Round worms

• Cylindrical body covered by exoskeleton (cuticle) that is shed (Ecdysis)
• Muscles are longitudinal → trashing motion
• non-segmented, Pseudocoelomates

Question 2

What are the Coelomate divisions

Answer 2

• Acoelomate - no cavity between Endoderm and Ectoderm
• Pseudocoelomate - cavity between Endoderm and Ectoderm
• Coelomate - cavity in the Mesoderm, surrounded on all sides by Mesoderm

Question 3

What is a Coelom

Answer 3

A coelom is a body cavity that is completely lined by mesoderm (not endo or ectoderm)

Different than a gut

Coelomates are divided into two groups based on developments: Protostomes and Deuterostomes

Question 4

What is Phylum Arthropoda

Answer 4

• name means “jointed feet”
• jointed appendages and segmented bodies (tagma)
• all are ecdysozoans since they shed their exoskeleton (cuticle) to grow
• Diverse, numerous; widespread and successful

Question 5

what are magma

Answer 5

Body segments that have a specific structure and function

Question 6

what is subphylum chelicerate

Answer 6

• Chelicerae: claw-like feeding appendages
• No antennae
• Marine (horseshoe crabs) and terrestrial
• Most modern chelicerates belong to the Arachnida

Question 7

what is class arachnida

Answer 7

• Six pairs of appendages
  
  • One pair of Chelicerae; can be equipped with venom glands
  • One pair of pedipalps - sensory, feeding, reproduction
  • four pairs of legs
  • e.g. mites, scorpions, spiders, ticks

Question 8

what is subphylum myriadopa

Answer 8

• terrestrial
• 2 tagmata: head and trunk
• head
  
  • one pair of antennae
  • mouthparts include mandibles
• trunk
  
  • uniramous (unbranched) appendages

Question 9

what are diploda

Answer 9

Diplopoda: millipedes

• tube shaped body
• short antennae
• trunk: 2 pairs of walking legs/segment
• herbivorous

Question 10

what are chelipoda

Answer 10

Chelipoda: centipedes

• flat body
• long antennae
• trunk: one pair of walking legs/segment
• carnivorous

Question 11

describe subphylum crustacea

Answer 11

• tagma: 2 or 3
• 2 pairs of antennae
• chewing mouthparts include a mandible
• biramous (branched) appendages
• three or more pairs of legs
• e.g. crabs, crayfish, lobsters, shrimp

Question 12

describe Insecta

Answer 12

Insecta

• 3 tagmata: head, thorax, and abdomen
• one pair of antennae
• Mouthparts
  
  • modified for chewing, sucking, or lapping
  • a mandible
• usually two pairs of wings
  
  • often modified for other purposes
• Usually three pairs of legs
• Uniramous appendage

Question 13

what is typical insect body plan

Answer 13

Includes a head, thorax, abdomen, antennae, eyes, mandibular mouth parts, 3 pairs of legs, 2 pairs of wings, tympanum, spiracles, and the ovipositor (female)

Question 14

describe Echinoderms

Answer 14

• Eucoelomate Deuterostomes
  -this group contains brittle stars, sea cucumbers, sea stars, and sea urchins
• Secondary radial symmetry
  
  • Bilateral larva > radial adult
• Hard calcareous endoskeleton
• Water vascular system
• Tube feet
  
  • locomotion
  • feeding
  • gas exchange

Question 15

describe subphylum Cephalochordata

Answer 15

Lancelets (or amphioxus)

• blade like or eel like shape
• small (few cm long) and bury in sand
• Chordate characteristics persist into adulthood

Question 16

describe subphylum Urochordata

Answer 16

• uro = tail; chord = string
• marine, may be solitary or colonial

As larvae:

• Planktonic
• Short-lived
• non-feeding
• have all chordate characteristics

As an Adult:

• sessile
• no notochord, nerve chord, or tail

Question 17

why are nematodes related to arthropods

Answer 17

Nematodes are related to Arthropods since they both periodically shed or molt their exoskeleton.

Question 18

how can nematodes move

Answer 18

They trash side to side by contracting the long muscles on either side of their body and wriggling forwards. Since they only have longitudinal muscles, they can only move like this.

Question 19

describe the shape of a nematode

Answer 19

All Nematodes are round with a body cavity. They have one way guts with a mouth at one end and an anus at the other. They have a pseudocoelom that is lined on one side with mesoderm and on the other side with endoderm.