Unit 6 Review #2 Q’s
1.
All Arthropods have the following – Jointed
appendages, Exoskeleton, Segmentation, Open
Circulatory System, Bilateral Symmetry.
2.
A) Crustaceans – The Crayfish
B) Chelicerates –. Spiders
C) Uniramia – Class Insecta – Grasshopper
3.
Crustacea have a harder exoskeleton as the
Chitinous exoskeleton is reinforced with CaCO3.
4.
An EXOSKELETON impedes growth and
movement – To overcome these problems
arthropods molt/shed their exoskeleton for
growth and they have many joints in their
appendages to facilitate movement.
5.
The waxy coating is the CUTICLE and it reduces
water loss.
6.
Appendages are any key structures that project
outward from the main trunk of the body. These
include specialized appendages for : Walking and
Jumping (legs), Flight (wings) Eating
(palps,maxillipeds) Reproduction (clasping and
sperm transfer), Sensing (antennae) and
Breathing (gills off walking legs).
7.
Arthropods have an open circulatory system, so the
heart pumps blood out into an open hemocoel
rather than through a closed network of blood
vessels. In an annelid we saw a closed circulatory
system, where blood was pumped around the body
but the blood stayed inside blood vessels.
8.
Being small in size has allowed insects to efficiently
use an open circulatory system, efficiently use an
exoskeleton, hide and quickly move. Small size has
increased their overall fitness for survival. Large
arthropods require a very large heavy exoskeleton,
one which would be difficult for movement. The
largest arthropods are found in the ocean, because
the buoyancy of water helps them move easily.
9.
Insects are the most successful of all animals due to
the fact that they are very mobile as they possess
small body size and the majority can fly, they have
rapid life cycles to allow for great reproductive rate,
they also show amazing diversity due to ability to
adapt to all kinds of niches.
Classes of Arthropods
1. Uniramia – Unbranched appendages (Class
Insecta) One pair of antennae, Three pairs of
legs and three body regions and usually two
pairs of wings.
Crustacea – Two pair of antennae, Exoskeleton
reinforced with CaCO3 and all have mandibles
for eating.
Chelicerata – (Class Arachnida) No antennae,
two body regions (cephalothorax and
abdomen) and Chelicera (fang-like structures).
2.
Typically, compound eyes, simple eyes (ocelli),
palps, antennae, sensory bristles, a tympanum
(eardrum).
CRAYFISH
3.
A cephalothorax is a region that consists of a
fused head and thorax.
4.
The carapace is a dorsal plate-like shell of
exoskeleton over the anterior end of a crab, or
crayfish to provide more solid protection of
vital organs.
5.
In Crustacea, the exoskeleton is Chitin (a
carbohydrate chemical) and CaCO3.
6.
A Cheliped is used for defense and for
capturing food and crushing it.
7.
The crayfish abdomen has 6 segments, 7 if
including the Telson.
BACK SIDE :
8.
Gastric Mill
9.
Digestive glands secrete enzymes to chemically
break down food.
10. Anus is under the Telson.
11. Crayfish brain is located just above the
esophagus which gives rise to a ventral nerve
cord.
12. A) Green glands
B) Antennules
C) Rostrum
D) 1st pair of swimmerets on male
E) Gastric Mill
F) Mandibles
13. Statocysts are found on antennules (shorter
antennae) and they are used for sense of
balance these shorter antennules are also
branched (biramous). The longer antennae are
not branched and they are more specialized for
touch.
14. Antennules  Mandibles  Maxillae 
Maxillipeds  Chelipeds  Walking Legs 
Swimmerets  Uropods
15. Internal and External
Grasshopper:
16. Insect body plan : Three body regions, three
pairs of legs, one pair of antennae, compound
eyes, and usually two pairs of wings.
17. The four main mouthparts of a grasshopper
include the LABRUM, MANDIBLES, MAXILLAE
and LABIUM.
18. Two large compound eyes surrounded by
three very small simple eyes.
19. These hind-legs are modified for JUMPING.
20. The forewings are hard and leathery for
protection and gliding, the hind-wings are
membranous and fanlike for flight.
21. The tympanum is/are located on the first
abdominal segment and they are specialized
for picking up vibration from sound waves.
22. Male grasshoppers deposit sperm into the
female's SPERMATHECA (Sperm Receptacle)
23. Ovipositors, these hook-like structures are
used for digging a chamber in the ground to lay
the fertilized eggs in.
24. Incomplete Metamorphosis : Three stages :
EGG  NYMPH  ADULT . Ex. Grasshopper
Complete Metamorphosis : Four stages: Egg  LARVA
 PUPA  ADULT. Ex. Butterfly, housefly, grain beetle
etc.
25. A PUPA is the resting stage during which the
insect undergoes a dramatic change from
juvenile body form to adult body form.
26. Grasshopper Digestive System:
Mouth  Esophagus  Crop Gizzard (proventriculus)
with surrounding Gastric Caeca Stomach (ventriculus)
 Intestine  Rectum  Anus.
27. Most insects use openings called Spiracles that
give rise to a Network of Tracheal Tubes each
of which branch and will terminate in a
microscopic air sac.
28. Spiracles
29. See diagram below
30. PROTHORAX  MESOTHORAX 
METATHORAX.