Arthropods

Question 1

Arthropod Morphology

Answer 1

Chitinous exoskeleton
Segmented body + appendages
Cuticle - chitin, derived from glucose, stiff but flexible

Question 2

Ecdysis

Answer 2

The shedding of an old skeleton + growing a new cuticle
Exoskeleton is dissolved - detached along sutures - new cuticle deposited
Each new molt leads to an instar stage

Question 3

Onycophorans

Answer 3

Cambrian to recent
Velvet worms
Poor fossil record (some in the Burgess shale) - few segments
Predators and detritovores

Question 4

Radiodonts

Answer 4

Cambrian to Devonian
Large bodied marine arthropods
Very active predators - could also be filter feeders + detritovores
Often found in multiple parts - not highly mineralized

Question 5

Trilobitmorphia

Answer 5

Cambrian to Permian
Calcitic exoskeleton - preserved very well
Marine
3 body regions + 3 lobes
Highly complex eyes

Question 6

Myriapoda

Answer 6

Cambrian to recent
Uniramous appendages
1 pair of antennae + 1 pair of mandibles
Poorly differentiated body sections
Chilopoda - centipedes - 1 pair of legs per segment
Diplopoda - millipedes - 2 pairs of legs per segment
First large animals to colonize land

Question 7

Pancrustacea

Answer 7

Cambrian to recent
Head w/2 pairs of antennae, 1 pair of mandibles, 2 pairs of maxillae
3 tagmata - cephalon, thorax, abdomen
Biramous appendages - have gils

Question 8

Hexapods

Answer 8

Devonian to recent
Insects + other small groups - most diverse subphylum
6 unbranched appendages, 1 pair of antennae, 3 pairs of legs