Terms To Know Lab 8

Question 1

Chelicerae

Answer 1

First pair of modified appendages , are found behind then the mouth
- they serve as fangs (spiders) or grasping food and defense
These are the first pair of walking legs in horseshoe crabs

Question 2

Pedipalps

Answer 2

Second pair of modified appendages.
These are usually enlongate and sensory in function (spiders), or in the form of pinchers (scorpions) for food gathering and defense

Question 3

Telson

Answer 3

Spinelike tailpiece (extends behind the abdomen)
In merostomata

Question 4

Spinnerets

Answer 4

In spiders, one pair of abdominal appendages persists as the silk producing spinnerets (used to construct the web).

Question 5

Swimmerets

Answer 5

Helps shrimps/lobsters to move easily while swimming (and carry eggs)

Question 6

Cephalothorax

Answer 6

In most crustaceans, one or more segments of the thorax have become fused with the head to form a cephalothorax

Question 7

Jointed appendages

Answer 7

Concerted limbs

• development of these helped arthopods move around (who had trouble before because of their chitinous skeleton)
• they (arthopods)also have specialized muscles to articulate these joints
• these also are equipped with sensory hairs.

Question 8

Abdomen

Answer 8

In chelicerata (all these animals)
Chelicerates are dived into two parts- the cephalothorax and the abdomen

Question 9

Carapace

Answer 9

Covers the cephalothorax and looks and acts like a shield

Question 10

appendages

Answer 10

-chelicerae serves as fangs in spiders ( pedipalps are elongate and sensory)
-in scorpions, pedialps serve as pinchers
And scorpions use chelicerae to grasp organs
-in crustacea, thoracic and abdominal appendages are mainly for walking and swimming, but some are highly specialized in function
-in crustacea,daphnia, some appendages are used as antennae)
(Some are Swimmerets in shrimp/lobsters)

Question 11

Adaptive radiation

Answer 11

A new structure (appendages formed from the exoskeleton) is modified in different descendants and used for many functions and habitats.
- reason for marine success of crustaceans (adaptive radiation dependent on exoskeleton)

Question 12

Gas exchange structures for horseshoe crabs, spiders/scorpions, crustaceans

Answer 12

• in horseshoe crabs, book gills (leaf-like structures) are used for locomotion and gas exchange
• in spiders/scorpions- book lungs that have parallel pages of structures surrounded by blood. Air enters the chambers by a slit in the body wall and the trachea carries the air to tissues through spiracles

Question 13

What structures are used for locomotion?

Answer 13

Horseshoe crabs- book gills
Spiders/scorpions- appendanges
Crustaceans- thoracic and abdominal appendages

Question 14

Function of krill/other microcrustaceans in the ecosystem

Answer 14

Major food sources of large marine anjmsld,filtering bristles, and feed on single celled algae

Question 15

sexual dimprphism

Answer 15

Male and female of same species differ in size