Section 30.4 (Exam 2)

Question 1

Arthropods are ecdysozoans with _______.

Answer 1

limbs

Question 2

Name the 4 major arthropod groups.

Answer 2

Chelicerates

Myriopods

Crustaceans

Hexapods

Question 3

Which 3 major arthropod groups have mandibles, and are called mandibulates?

Answer 3

Myriopods, crustaceans, and hexapods

Question 4

Describe what tardigrades (water bears) and velvet worms have in common.

Answer 4

They are ecdysozoans with fleshy, unjointed appendages

Question 5

What are trilobites?

Answer 5

Ancestors of arthropods with an abundant fossil record

They were the first to have jointed legs, and some of their appendages were modified for different functions

Question 6

Name 3 groups of animals that belong to the arthropod group, chelicaerates.

Answer 6

Sea spiders, horseshoe crabs, and arachnids

Question 7

What are some characteristics of chelicerates?

Answer 7

Two-part body

Head has two pairs of appendages modified into mouthparts, chelicerae; most have four pairs of walking legs

Question 8

What are the two parts of a chelicerate body?

Answer 8

Cephalothorax and abdomen

Question 9

What are chelicerae?

Answer 9

Present in chelicerates, two pairs of appendages that are modified into mouthparts.

Question 10

Describe horseshoe crabs.

Answer 10

Changed very little over their evolutionary history – living fossils

Common in shallow marine waters along eastern North America and Asia.

Come into the intertidal zone in large numbers to mate and lay eggs.

Question 11

Name all the different kinds of arachnids.

Answer 11

Spiders, scorpions, harvestmen (daddy long legs), mites, ticks

Question 12

Describe the simple life cycle of arachnids.

Answer 12

Miniature adults hatch from eggs and begin independent life.

Question 13

What is a common trait of mites and ticks?

Answer 13

Parasites of plants and animals

Question 14

Describe spiders.

Answer 14

Predators; chelicerae inject venom into prey

Some have excellent vision for prey capture; others spin elaborate webs to snare prey

Question 15

Name two myriapods.

Answer 15

Centipedes and millipedes

Question 16

What are some shared features of myriapods?

Answer 16

Head and a long, flexible trunk with many pairs of legs

Question 17

What differentiates centipedes and millipedes?

Answer 17

Centipedes—1 pair of legs per segment

Millipedes— 2 pairs of legs per segment (2 segments are fused)

Question 18

Name the three groups crustaceans are divided into.

Answer 18

Decapods, isopods, and everything else

Question 19

Name the decapod crustaceans.

Answer 19

Shrimps, lobsters, crayfish, and crabs

Question 20

Name the isopod crustaceans.

Answer 20

Pill bugs

Question 21

Name the crustaceans that aren’t isopods or decapods.

Answer 21

Amphipods, ostracods, branchiopods, copepods, and barnacles

Question 22

Name the 3 crustacean and hexapod (insect) body regions.

Answer 22

Head, thorax, and abdomen

Question 23

The head segments of crustaceans are _______ and they have 5 pairs of ______________.

Answer 23

fused; appendages

Question 24

Thoracic and abdominal segments of crustaceans have _________ pair of appendages each.

Answer 24

one

Question 25

What are the different functions that crustacean appendages can be specialized for?

Answer 25

Gas exchange, chewing, food capture, sensing, walking, and swimming

Question 26

What is a crustacean carapace?

Answer 26

A fold of exoskeleton that extends over the head and thorax region

Question 27

Hexapods have _______ legs.

Answer 27

six

Question 28

Which two groups do hexapods include?

Answer 28

Insects and wingless relatives of insects

Question 29

How many appendages are on the insect head?

Answer 29

One pair of antennae

Question 30

How many appendages are on the insect thorax?

Answer 30

Three pairs of legs and two sets of wings in most groups

Question 31

How many appendages are on the insect abdomen?

Answer 31

No appendages

Question 32

Insects also undergo ________________.

Answer 32

metamorphosis

Question 33

What is metamorphosis?

Answer 33

Substantial physical changes that occur between life stages.

Question 34

What is the difference between incomplete and complete metamorphosis?

Answer 34

Incomplete metamorphosis: changes are gradual. Examples: grasshoppers and roaches

Complete metamorphosis: changes are dramatic. Examples: butterflies and moths