Bio 108 - Lecture 20

Question 1

Recent Changes of Phylogeny of Arthropoda

Answer 1

• Hexapods and myriapods used to be sister taxa

- Hexapods now places with crustaceans, new clade called pancrustacea

Question 2

Tagmata of Arthropods

Answer 2

Head an thorax sometimes merge as cephalothorax

Head top, thorax middle, abdomen, back

Question 3

Subphylum Trilobita

Answer 3

• Wiped out in end-permian
• 1 antennae
• Pair of compound eyes
• Many biramous

Question 4

Physical Features of Subphylum Crustacea

Answer 4

• 2 pairs of antennae
• Biramous limbs
• Head and thorax merged to form cephalothorax
• Covered by carapace
• Mouthparts are mandibles
• Exchanges gas through gills
• Use tracheae

Question 5

Mandibles

Answer 5

Single segmented moutparts for biting / chewing

Question 6

Crustacean Life Cycle

Answer 6

• Only hermaphroditic species is barnacles
• Copulation sperm transfer
• Femals brood their eggs until hatch
• Most direct developers
• Most start out with sex limped nauplius larvae

Question 7

Ecology and Importance of crustaceans

Answer 7

Some filter feed, scavenge, or prey on fish
Some are commensals or parasites
- Value for food
- Bottom trawling to catch them is bad

Question 8

Hexapods Defining Features

Answer 8

• Insects
• 6 Legged
• Includes class Insecta
• And Class Collembola

Question 9

Morphology of Hexapods

Answer 9

• Head, Thorax, Abdomen
• Mandibles enclosed by cheeks in collembola
• Mandibles not enclosed by cheeks in Insecta
• Furcula used for jumping
• Ventral projection used for osmoregulation called collophore
• Wings
• Compound eyes

Question 10

Entognathous vs Ectognathous

Answer 10

Ento - Mandibles are enclosed

Ecto - Mandibles not enclosed

Question 11

Hexapod Life Cycle 3 Main variations

Answer 11

1) Ametaboly: Young look exactly like adult
2) Hemimetaboly: Wings slowly develop, young are called nymphs
3) Holometaboly: Wings develop at once during pupa stage, Juveniles called larva

Question 12

Other Characteristics of Life Cycle for Hexopods

Answer 12

All shed ectocuticle
In direct sperm transfer
All Prerygot insects copulate

Question 13

Ecology and Importance of Hexopods

Answer 13

• All terrestiral
• Polinate flowers
• Colony-collapse disorder is a dissaster

Question 14

Myriapoda

Myria =

Answer 14

= A great many

• Only have head and trunk
• All terrestrial, oldest knows fossils of terrestrial animals

Question 15

Class Diplopoda

Answer 15

• Millipedes
• Two pairs of legs and two stigma
• Diplosegments because adjacent segments fuse

Question 16

Class Chilopoda

Cheilos=

Answer 16

• Centepedes
• Modified legs behind mouthparts
• Poison claws used to subdue prey
  = Lip

Question 17

Chelicerata
Chel=
Cereos=

Answer 17

• Have chelicerae as main mouthparts
• 2 Tagmata
  (Prosoma and Opisthoma)
• Cephalothorax and abdomen
  = claw
  = horn

Question 18

Class Xiphosura
Xiphos=
Uros=

Answer 18

• Horeshoe Crabs
• Compound eyes
• Book Gills
• Long terminal spine
• Eat dead plants and animals by ingesting particles
• Larvae are planktonic
  = Sword
  = Tail

Question 19

Class Arachnida

Answer 19

• Spiders

- Fluid feeding predators

Question 20

Order Araneae

Answer 20

• Spiders
• 2 segmented chelicerae
• Spinnerets
• Gas exchange through tracheae and book lungs
• Poison glands
• Maternal care
• Suck up sperm using pedipalp

Question 21

Order Scorpiones

Answer 21

• Pedipals modified as grasping pincers
• Segmented
• Poisonous sting

Question 22

Order Acari

Answer 22

• Mites
• Many fluid feeders but detritivores can ingest solid particles
• Youth hatch with only 3 pairs of legs
• Youth called larvae
• Most economically important arachnids