Arthropods Lecture 15 + 16

Question 1

Major groups of Arthropods (5)

Answer 1

Trilobites
Myriapodia 
Chelicerata
Crustaceans
Hexapods

Question 2

Sub-phylum Myriapoda

Answer 2

Features: body and long repeated trunk
one pair of antennae
many limbs on trunk
(EX) millipedes and centipedes

Question 3

class Chilopoda

Answer 3

one pair of legs per segment (Centipedes)
flattened or round head and long mandibles
forcipules (no other arthropods)
predatory

Question 4

class Diplopoda

Answer 4

two pairs of legs per segment (Millipedes)
long, cylindrical bodies
detritivores

Question 5

Myriapod evolution

Answer 5

oldest known true land animal
largest land invertebrate
first evidence of tracheal air breathing (high O2 levels)

Question 6

Sub-phylum Trilobita

Answer 6

extinct group of Arthropods
exclusively marine
body- cephalon, thorax and pygidium
body divided into 3 lobes and one pair of antennae

Question 7

Trilobite fossil record

Answer 7

helped prove continental drift
estimate speciation rates in Cambrian
most diverse group of metazoans in fossil record

Question 8

sub-phylum chelicerata

Answer 8

body: cephalothorax and abdomen
two pairs of appendages on anterior of cephalothroax: chelicerae and pedipalps
4 pairs of walking legs

Question 9

classes of chelicerata (3)

Answer 9

Merostomata (horseshoe crabs)
Pycnogonida (sea spiders)
Arachnida (spiders, scorpions, ticks, mites)

Question 10

Sub-phylum Hexapoda

Answer 10

body: head, thorax and abdomen 
1 pair of antennae
3 pairs of mouth appendages
3 pairs of legs on thorax
1-2 pairs of wings

Question 11

classes of Hexapoda (2)

Answer 11

Entognatha- mouth inside (no wings)

Insecta- in sections (wings)

Question 12

Myriapods and Hexapods

Answer 12

linked through tracheal air systems
- convergent evolution for life on land
(**insects evolved from freshwater habitats to terrestrial in the Devonian)

Question 13

Hexapod metamorphosis (2)

Answer 13

Hemimetabolous- instars (no wings, are not sexually mature until last molt)- true bugs (grasshoppers)
Holometabolous- larvae, pupa, adult (beetles, butterflies)

Question 14

Sub-phylum Crustacea

Answer 14

body: cephalothorax and abdomen

2 pairs of antennae and 3 pairs of mouth appendages

Question 15

classes of Crustaceans (6)

Answer 15

Branchiopoda
Maxillopoda
Ostracoda
Malacostraca
Remipedia
Cephalocarida

Question 16

Branchiopoda

Answer 16

legs flattened (gill-like)
most fw, except brine shrimp

Question 17

Maxillopoda

Answer 17

no appendages on abdomen

barnacles, copepods

Question 18

Ostracoda

Answer 18

Bivalve shell

“seed shrimp”

Question 19

Cephalocarida

Answer 19

horseshoe shrimp

Question 20

Remipedia

Answer 20

primitive and elongate

swim on backs

Question 21

Malacostraca

Answer 21

most diverse class
each segment bears an appendage

Question 22

Malacostraca classes distinguished by

Answer 22

1. number of tagmata (specialized groups of segments with special functions)
2. number of segments per tagmatum
3. number of thorasic segments covered by carapace
4. number of segments fused with the carapace
5. presence/absence of moveable spines on telson

Question 23

shared features in Malacostraca (3)

Answer 23

21 segments
stalked eyes in adults
limbs on abdominal segments

Question 24

body forms in Malacostraca (3)

Answer 24

shrimp-like
crab-like
lobster-like

Question 25

Respiration in Arthropods

Answer 25

oxygen extracted from external environment to be delivered to tissue cells for energy requirements