Class Crustacea

Question 1

What is ecydysis?

Answer 1

Since the exoskeleton does not grow with body they need to molt, molting is hormonally and environmentally controlled.

Question 2

Respiration in crustaceans

Answer 2

Smaller crustaceans exchange gases across thinner áreas of exoskeleton
Large crustaceans featherlike gills which Are protected by carapace

Question 3

Excretion in crustaceans

Answer 3

All crestaceans excrete ammonia over their gills and via excretory organs called nephridia

Question 4

Reproduction in crustaceans

Answer 4

Mostly dioceious , testes/ovaries in cephalothorax, most crustaceans brood eggs, some have elaborate courtship behavior.
In males abdomen is narrow vice versa in females

Question 5

Eyes in crustaceans

Answer 5

Nauplius larvae: single eye

Adults: often have compound eyes

Question 6

Characteristics of brachiopoda

Answer 6

Primitive forms, mostly freshwater , reduced first antena and 2nd maxillae, legs often flattened, setae in limbs, eat plankton or detritus.

Question 7

Characteristics of copepoda

Answer 7

Free-living plankton, major food for fish, sometimes parasitic , lack carapace, antennules used for swimming.

Question 8

Characteristics of branchiura

Answer 8

Marine/freshwater , flattened body covered by carapace (lack gills), mostly ectoparasites , 2nd maxilla modified as suckers.

Question 9

Characteristics of cirripedia ( barnacles)

Answer 9

Mostly sessile, head reduced and abdomen absent, thoracic legs ( 6 pairs for feeding), filter feeders, hermaphrodites , some parasitic in crabs, cyprid larvae settles and attaches permanently to hard substrate.

Question 10

Characteristics in malacostracs ( crabs, lobsters, prawns)

Answer 10

Antennules: chemosensory
Antennae: tactile and chemosensory
Eyes : sight
Mandibles : maxillae and maxilla
Rostrum
Cephalothorax : 8 thoraxic appendages , walking legs 
Abdominal appendages : swimming legs
Tail: telson and uropod - used for balance and stability

Question 11

Characteristics of isopoda ( slaters, woodlice, “sea lice”)

Answer 11

Terrestrial / marine, dorsoventrally flattened, no carapace , free-living / parasitic forms.

Question 12

Characteristics of amphipodia (sand hoppers)

Answer 12

Terrestrial/ marine and freshwater , laterally compressed , no carapace , free-living and parasitic forms

Question 13

Characteristics of krill

Answer 13

Small planktonic crustacean, wide variaty of animals feed in it, form huge swarms.

Question 14

Characteristics of crustacea

Answer 14

Triploblastic , bilateral symmetry , two main body parts, mandibles, jointed appendages, nauplius larvae, most possess gills, chitinous exoskeleton reinforced with CaCO3, two pairs of antennae