L11 Arthropods cont

Question 1

What are the shared features of the crustaceans?

Answer 1

Two pairs of antennae, biramous appendages
Cephalon head section
Trunk is segmented, each has an appendage
Carapace

Question 2

What classes are found in the crustaceans?

Answer 2

Maxillopda, Malocostraca, ostaracoda, branchiopda

Question 3

Describe the biramous limbs of the crustaceans

Answer 3

Made of an exopod, the internal branch, which is used for respiration, and an endpod, the external branch, which is used for walking or swimming

Question 4

What is a rostrum?

Answer 4

Beak like projection on the head, e.g. crayfish

Question 5

What are the general characteristics of Malacostraca?

Answer 5

2 pairs of antennae
1-3 thoracic appendages
Mandibles for feeding
Maxilla appendages for feeding
Biramous appendages 
e.g. crayfish

Question 6

What are brine shrimps?

Answer 6

In Branchiopoda, swim on their backs, have many unmodified appendages which move in metachromal waves

Question 7

What are water fleas?

Answer 7

In Branchiopoda
Transparent, with a single eye, mostly thorax, entirely enclosed in a carapace. Are parthogenetic in normal conditions, sexual in stress

Question 8

What animals are in maxillopoda?

Answer 8

Barnacles and copepods

Question 9

Describe the baluns barnacles

Answer 9

Sits on back in shell, which is made of calcium salts.
Hox gene Abd-A not expressed. Hermaphrodite.
Have longest penis to body ratio in animal kingdom
Valves of shell may close over in dry conditions

Question 10

What are parasite barnacles?

Answer 10

Change the behaviour of the crab - makes males more female, once ready to release eggs, stimulate crab so behaves as if releasing eggs, so aids in dispersal of barnacles offspring

Question 11

What are the myriapods?

Answer 11

Centipedes and millipedes

Question 12

What are the general characteristics of the myriapods?

Answer 12

Two tagmata

Question 13

What are the general characteristics of centipedes?

Answer 13

Dorsoventrally flattened
Carnivorous
2 specialised maxillae 
specialised head
Maxilliped - poison claw for predation

Question 14

What are the general characteristics of millipedes?

Answer 14

One pair of antennae
Spherical body, legs dangle from the bottom
Have hydrogen cyanide gas to prevent predation
Feed on plant/decaying matter

Question 15

How do the myriapods do gas exchange?

Answer 15

Gasses diffuse through tracheoles , can’t be closed and therefore are restricted to damp environments

Question 16

What are malpighian tubules?

Answer 16

Excretory device, like metanephridium, where osmoregulation occurs

Question 17

What are Hexapoda? What are their general characteristics?

Answer 17

Insects
Have 3 tagmata
spiracles can close and open, so are adapted to terrestrial life
3 pairs of walking legs, can have two pairs of wings

Question 18

What are the advantages of having an exoskeleton

Answer 18

Allows complex movements with jointed appendages

Provide protection

Question 19

What are the disadvantages of having an exoskeleton?

Answer 19

Cannot stretch or expand
Modifications required for gas exchange
Needs to be shed at regular intervals