Invertebrate Diversity 2

Question 1

Phylum: Nematoda

Answer 1

roundworms.

• Non-segmented worms
• Longitudinal muscles
• Alimentary canal
  
  • separate mouth and anus
• No circulatory system
  
  • small = no need
• Ubiquitous in the environment
• Free living and parasitic
  
  • Filariasis nematode can cause elephantiasis (aka elephantitis)
  • Trichinosis caused by nematode larvae encysted in muscle.
  • Guinea worm –Rod of Asclepius may be based on this nematode

Question 2

Nematodes are the most abundant animals in the world in number and biomass

Answer 2

60% are parasitic

- 4 out of 5 animals on earth are nematodes

Question 3

Phylum: Nematoda

Free living and parasitic

Filariasis

Answer 3

Filariasis nematode can cause elephantiasis (aka elephantitis)

Question 4

Phylum: Nematoda

Free living and parasitic

Trichinosis

Answer 4

Trichinosis caused by nematode larvae encysted in muscle.

Question 5

Phylum: Nematoda

Free living and parasitic

Guinea worm

Answer 5

Guinea worm –Rod of Asclepius may be based on this nematode

Question 6

Phylum: Arthropoda

Unifying Traits

Answer 6

jointed feet

1. Bilateral symmetry
2. Segmented body
3. Hard exoskeleton
   a. desiccation resistant
   b. Made of chitin
   c. muscle attachment
   d. molt (ecdysis)
4. Jointed legs
5. Many pairs of limbs that provide specialization
6. complete gut
7. open circulatory system

Question 7

Phylum: Arthropoda

Evolution

Answer 7

Evolved from segmented worms

- Segments fuse over time and specialize

Question 8

Phylum: Arthropoda

Classes

Answer 8

5 classes; trilobites are extinct 250MYA

1. Cheliceriformes
2. Myriapoda
3. Hexapoda
4. Crustacea

Question 9

Phylum: Arthropoda

Class:

Cheliceriformes

Answer 9

spiders, ticks, horseshoe crabs, scorpions

a. Chelicera - claw-like feeding appendage
	- different than mandibles
b. no antennae
c. cephalothorax - fused head and thorax
	- 2 basic body parts
- variety of leg amounts
- horseshoe crabs are not crabs but these

Question 10

Phylum: Arthropoda

Class:

Myriapoda

Answer 10

millipedes (herbivores; 2 pair legs per segment)

- tend to be herbivores 
- emit cyanide and benzoquinones
	- act as an insect repellent and a hallucinogenic 

centipedes (carnivores; 1 pair legs per segment)
- carnivores

Question 11

Phylum: Arthropoda

Class:

Hexapoda

Answer 11

insects

• 3 main body parts (head, thorax and abdomen)
• 3 pair walking legs (hence name, hexapoda)
  
  • “6 foot”
• 2 antennae

Question 12

Phylum: Arthropoda

Class:

Crustacea

Answer 12

crabs, shrimps, barnacles, lobster)

• Marine and freshwater; a few terrestrial

Question 13

Phylum: Echinodermata

Answer 13

starfish, brittle stars, sea cucumbers, sea urchins, etc.

“Spiny Skins”

Question 14

Phylum: Echinodermata

Unique characters

Answer 14

1. Deutoerostomes
   
   • Humans are too
2. Endoskeleton of calcareous plates
3. water vascular system - hydraulic system of closed tubes containing sea water; used for locomotion (tube feet), food and waste transport and respiration
   
   • only in Echinoderms
4. larvae bilateral; adults radial symmetry (i.e. radial symmetry is homoplasic)

Question 15

5 Major Milestones

Answer 15

1. Diploblstic, no tissues, asymmetry(Metazoa)
2. True tissues/radial symmetry(Eumetazoa)
3. Bilateral Symmetry/triploblastic(Bilateria)
4. Alimentary canal(between Bilateria and Protosome/Deuterostomia split)
5. Circulatory System(open or closed)(between Bilateria and Protosome/Deuterostomia split)