Exam 3 Ch 20

Question 1

External features

Answer 1

cuticles made of chitin, protein and calcareous material. Caraspare covers most of cephalothorax

Question 2

Tergum

Answer 2

Dorsal cuticular plate that covers each segment not enclosed by caraspace

Question 3

Pleurites

Answer 3

2 lateral covering plates that form the pleuron

Question 4

Sternum

Answer 4

Ventral transverse bar that lies between segmental appendages

Question 5

Gonopores

Answer 5

Position varies according to sex and group of crustaceans

Question 6

Protopod

Answer 6

(appendage) basal portion

Question 7

Endopod

Answer 7

Medial

Question 8

Exopod

Answer 8

Lateral

Question 9

Serial Homology

Answer 9

Many biramous appendages (modified to do multiple functions) are homologous to each other. Crayfish possess most elaborate in animal kingdom

Question 10

Crustacea are mostly marine…

Answer 10

• have 2 pairs of antennae
• mandibles
• 2 maxillae on head
• all appendages are biramous (2 main branches)
• most have 16-20 segments, but some have around 60

Question 11

Cephalothorax

Answer 11

One or more thoracic segments are fused w head

Question 12

Largest class…

Answer 12

Malacostraca. Lobsters, crabs, shrimp, etc. 5 heads, 8 thorax, 6 abdomen segments

Question 13

Carapace

Answer 13

covering from dorsal cuticle of head

Question 14

Hemocoel

Answer 14

Major body space in arthropods is a persistent blastocoel that is blood filled

Question 15

Muscular system is mostly made up of…

Answer 15

striated muscles…flexors that draw apart towards the body and extensors that extend the part outward

Question 16

Respiratory system

Answer 16

Gas exchange occurs across thin areas of cuticle. Large crustaceans have gills. Caraspace overlaps gill cavity leaving anterior and ventral openings

Question 17

Circulatory system

Answer 17

no veins and no separation of blood from interstitial fluid

Question 18

Hemolymph (blood and interstitial fluid)

Answer 18

part of the circulatory system. Leaves heart through arteries, circulates hemocoel and returns to sinus spaces before entering heart. Hemolymph enters heart from surrounding pericardial sinus, into one or more arteries. Valves prevent backflow. Small arteries empty into tissue sinuses which discharge into large sternal sinus. From there hemplymph is carried to gills.

Question 19

Hemolyanin

Answer 19

Copper containing respiratory pigment

Question 20

hemoglobin

Answer 20

iron containing respiratory pigment

Question 21

Excretory system

Answer 21

pair of tubular structures located in ventral part of head. Antennal glands/maxillary glands. Depending on where they open. Filtrate is excreted as urine after resorption of salts, amino acids, glucose, and some water

Question 22

Nervous System and sensory systems

Answer 22

supraesophageal ganglia- brain consists of this pair that supplies nerves to eyes and two pairs of antennae
Subesophageal ganglion - fusion of at least 5 pairs of ganglia that supply serves to mouth, appendages, esophagus, and antennal glands

Question 23

tactile hairs

Answer 23

delicate projections of sensory cuticle. Increase pigmentation to attract. vision and orientation are biggest.

Question 24

Ommatida

Answer 24

compound eyes, composed of many photoreceptor units

Question 25

Statolith

Answer 25

give 3D orientations to surroundings

Question 26

Setae

Answer 26

sensing surroundings

Question 27

functions of setae

Answer 27

chemoreception - if crab smells another crab molting, it will molt too Mechanoreception - feeling something on leg w/out looking Physical attachments: ovigerous - hairs to hold eggs on belly Decorator - put things on shell to blend Filter Feeding - wave arms and eat what collects

Question 28

Molting

Answer 28

process of making large cuticle and ecdysis, shedding of cuticle to become larger

Question 29

Cuticle

Answer 29

secreted by underlying epidermal cells

Question 30

Epicuticle

Answer 30

outermost layer

Question 31

Exocuticle

Answer 31

chitin, calcium salts, protein

Question 32

Endocuticle

Answer 32

heavily calcified initial layer and uncalcified membranous layer

Question 33

Epidermis

Answer 33

columnar cells that elongate based on water absorption, secreted cuticles

Question 34

Ecdysis

Answer 34

massive energetic process that affects behavior, metabolism, reproduction. Often occurs in younger organisms, slows or may cease in adults

Question 35

MIH

Answer 35

Molt-inhibiting hormone (secreted by Xorgan). Xorgan affects pigmentation and is in eyestalk

Question 36

Feeding habits

Answer 36

varies greatly among crustaceans. Filter feeding, predation, deritivores. Have highly specialized appendages to aid different feeding types

Question 37

Gastric mill

Answer 37

first part of the crayfish stomach where food is further ground by three calccerous teeth into particles fine enough to pass through setae filter in 2nd part

Question 38

Crustaceans

Answer 38

over 67,000 species (study worksheet)

Question 39

Malacostraca

Answer 39

Most diverse copepoda (fresh and salt water) and ostracoda (fresh water). These are most abundant.