Post-Midterm Pt 2

Question 1

What mouth parts/antennae do Crustaceans have?

Answer 1

2 pair antennae (1st uniramous, 2nd biramous), 1 pair mandibles, 2 pair maxillae

Question 2

Describe the crustacean larva

Answer 2

Called “nauplius”, have 3 sets of limbs (all for swimming) - 1st antennae, 2nd (biramous) antennae, and a biramous “mandible” which becomes the mandible in the adult

Question 3

The thoracic appendages of crustaceans are called ______

Answer 3

Periopods

Question 4

The abdominal appendages of crustaceans are called _____. What is their function?

Answer 4

“Pleopods”. Can help in swimming but may be modified in males for sex. May hold eggs in females.

Question 5

What is unique about the anterior thoracic limbs of crustaceans?

Answer 5

May be modified as claw-bearing structures

Question 6

Describe the life cycle of the anchor worm, “Lernea”

Answer 6

Starts as nauplius larva, burrows into fish. There it grows “anchors” (basically little hooks) off the cephalothorax and the abdomen elongates, and mouth and gut disappear

Question 7

Describe the basic features of the chelicerata

Answer 7

Includes spiders, scorpions. Have no antennae, mandibles, or maxillae. Instead have two pairs of head appendages called chelicerae and pedipalps. Usually have 4 pairs of locomotory appendages.

Question 8

How are the bodies of chelicerates divided? How do these differ from others?

Answer 8

Into Prosoma - cephalothorax and opisthosoma - posterior behind cephalothorax. Opisthosoma includes respiratory organs and heart as well.

Question 9

_____ are mites that burrow into human skin, causing inflammation and turning the skin red

Answer 9

Scabies

Question 10

In scorpions, the claws are formed by _____

Answer 10

The first pair of walking legs

Question 11

When chelicerates feed, they engage in pre-oral digestion. What is this?

Answer 11

Occurs when chelicerates inject prey with digestive enzymes so they can drink the body contents

Question 12

Describe the basic insect body structure

Answer 12

Divided into head, thorax, and abdomen.
Head has 6 segments with 1 pair mandibles, 1 pair antennae, 1 pair maxillae.
Thorax has three segments, prothorax, mesothorax, and metathorax. Each bears 1 pair legs.
Abdomen has 11 segments

Question 13

Wings of insects are found on the _____ and _____

Answer 13

Mesothorax and metathorax

Question 14

What is the primary function of the insect abdomen

Answer 14

Reproduction. Egg storage and such

Question 15

Moths and butterflies are of the order _____

Answer 15

Lepidoptera

Question 16

What is unique about cicadas

Answer 16

Live underground for years, randomly emerge in swarms of thousands.
Have no predators because nothing can adhere to their weird schedules

Question 17

What is the common name of the order Coleoptera? What makes them unique

Answer 17

Beetles. Forewings form a hard shell called the “elytra” that protects the hind wings

Question 18

The bees, wasps, and ants belong to order _____

Answer 18

Hymenoptera

Question 19

Describe insect order Diptera

Answer 19

True flies with only 1 pair flying wings

Question 20

The dragonflies are in order ____

Answer 20

Odonata

Question 21

What does the word “echinoderm” mean?

Answer 21

Spiny skin

Question 22

Briefly describe class Stelleroidea of the Echinoderms

Answer 22

Contains the Asteroidea (sea stars) and the ophiuroidea (brittle stars).

Question 23

Describe the Asteroidea

Answer 23

Sea stars. Have a large coelomic cavity that extends into the arms, with open ambulacral grooves on the oral surface

Question 24

Describe the Ophiuroidea

Answer 24

Includes brittle stars (ex. Gorgonocephalus). Arms set off from a central disk, have no ambulacral grooves, arms filled with calcified ossicles (very thin with no water-vascular system)

Question 25

Describe the Crinoidea

Answer 25

Includes the sea lilies and feather stars. Have branched arms with pinnules to increase surface area for feeding. Unlike the Stelleroidea, the Crinoidea’s oral side is directed upwards. They appear in both stalked and free moving forms

Question 26

Describe the Echinoidea

Answer 26

Includes sea urchins, sand dollars, Heart urchins.
They have no arms, are slightly spherical or dorso-ventrally flattened. Ossicles are fused to form a solid skeleton (called test)

Question 27

Describe the Holothuroidea

Answer 27

Body elongated along oral-aboral axis. Are kind of cylindrical, may be slightly flattened in cross section. Skeleton is reduced to microscopic ossicles.

Question 28

The Echinoderms are the only invertebrates that are _____. What does this mean?

Answer 28

Deuterostomes. Embryologic blastopore becomes the anus

Question 29

What Echinoderm trait makes them more similar to Vertebrates than other Inertebrates? What does this mean?

Answer 29

Echinoderms are deuterostomes (just like all vertebrates). Embryologic blastopore becomes the anus

Question 30

Describe the basic characteristics of the Echinoderms

Answer 30

Exhibit pentaradial symmetry, with the body arranged in 5 parts around a central axis. Have an endoskeleton of calcareous ossicles in body wall. Have spines or tubercles projecting through the epidermis.
Most have a water-vascular system. There is no cephalization and they are divided into oral (mouth bearing) and aboral surfaces.

Question 31

Describe the skeleton of the Echinoderms

Answer 31

Have an endoskeleton of calcareous ossicles in body wall, which can link together to form a flexible skeleton or fuse to form a rigid “test” (is reduced to be microscopic in Holoturoidea). Have spines or tubercles projecting through the epidermis.

Question 32

What makes the Crinoidea unique when compared to other Echinoderms?

Answer 32

Oral surface is dorsal instead of ventral

Question 33

Describe the water vascular system of Echinoderms

Answer 33

Internal, closed system filled with water. Internal surface is ciliated and water enters through madreporite. The stone canal leads from the madreporite to the circular duct around the mouth, which splits off into radial vessels (1 through each arm). Tentacle-like outpocketings called “tube feet” protrude from the skin.

Question 34

What is the purpose and structure of Echinoderm tube feet? How do they move?

Answer 34

Suckered feet adhere to substrate and may function in movement, seizing/holding prey, passing food to mouth, and as respiratory organs.
They move by contracting a reservoir (“ampulla”) above the foot to generate hydrostatic pressure

Question 35

What are the two portions of the Enterocoel of the Echinoderms

Answer 35

Perivisceral coelom - Around viscera

Hydrocoel coelom - Forms water vascular system (distinct from perivisceral)

Question 36

Describe the digestive system of Echinoderms

Answer 36

Begins at mouth, ends at anus, lined by endoderm. Lateral evaginations close to the anus form digestive glands that may also store food. The anus removes very little waste, as most excretion is performed by the papillae and tube feet

Question 37

What is unique about the digestive system of the Asteroidea

Answer 37

Many digest food outside the body, extracellularly. Thus, no waste and very little need for digestion

Question 38

What is unique about the feeding method of the class Echinus

Answer 38

Feed using a structure called “Aristotle’s Lantern”. It is an apparatus used to scrape rocks and other substrates. Consists of 5 teeth operated by muscles, and can be protruded slightly when in use

Question 39

How do varying Echinoderm classes respirate?

Answer 39

The Stelleroidea respirate using dermal papillae (skin gills), Holothuroidea take in air through their cloaca (which then enters the respiratory tree), and Echinoidea use tube feet

Question 40

Describe the nervous system of Echinoderms

Answer 40

Divided into one or more nerve rings surrounding the mouth. These give off radial nerves into the arms (similar to water-vascular system)

Question 41

Describe reproduction in Echinoderms

Answer 41

Most have 2 sexes and external fertilization. Usually have 10 gonads (2 per arm), each in a genital sac. Each gonad has a duct connected to a gonopore which opens near the base of arms or, where no arms are present, between ambulacral zones. Gametes are shed seasonally

Question 42

Describe fertilization in Echinoderms

Answer 42

Eggs are very small and surrounded by a jelly-coat. The sperm are flagellated, and the fusion of the two produces a diploid zygote. Eggs stick to substrate using their viscous covering.

Question 43

Sea star larvae are called _____

Answer 43

“Brachiolaria”

Question 44

Describe the mutable connective tissue of Echinoderms. Give examples of how different Echinoderms do this

Answer 44

Echinoderms can change the consistency of their connective tissue to an almost liquid form. This results from changing the polymerization of collagenous tissue in the dermis (by changing concentration of Ca++ ions).
Sea urchins stiffen dermis to anchor spines so they can lodge in a crevice or scare off predators.
Sea stars stiffen dermis to provide a scaffold against which they can pry bivalves open.