Lab 27

Question 1

Radial symmetry

Answer 1

body parts are arranged around a central axis to radiate out like the spokes of a wheel.

Question 2

Bilateral symmetry

Answer 2

Symmetrical arrangement of an organism or part of an organism along a central axis, so that the organism or part can be divided into two equal halves.

Question 3

Incomplete digestive tract

Answer 3

what goes in the mouth comes back out the mouth.

Question 4

Complete digestive tract

Answer 4

a digestive tract with two openings, a mouth and an anus.

Question 5

Coelom

Answer 5

The body cavity in multicellular, eukaryotic animals.

Question 6

Acoelomates

Answer 6

Do not have a coelom between the digestive system and the outer body wall.

Question 7

Pseudocoelomates

Answer 7

The coelom is derived from both the endoderm and the mesoderm.

Question 8

Eucoelomates

Answer 8

The coelem is derived from only mesodermal tissues.

Question 9

Protostomes

Answer 9

A major group of animals in which the blastopore gives rise to the mouth.

Question 10

Deuterostomes

Answer 10

A major group of animals in which the blastopore gives rise to the anus.

Question 11

Sponge

Answer 11

The simplest of the multicellular animals believed to have evolved from choanoflagellates.

Question 12

Spicules

Answer 12

needle-like anatomical structure that support sponges.

Question 13

Spongin

Answer 13

the horny or fibrous substance found in the skeleton of many sponges.

Question 14

Ostia

Answer 14

Allows water to enter the interior of the sponge

Question 15

Spongocoel

Answer 15

Central cavity lined with choanocytes.

Question 16

Osculum

Answer 16

Large opening that allows water to leave the sponge.

Question 17

Mesohyl

Answer 17

A gelatinous matrix that houses the cells of sponges.

Question 18

Ameobocyte

Answer 18

Absorbs, transports, and digests food.

Question 19

Asconoid canal system

Answer 19

A canal system in which water enters the sponge via tiny Ostia in the dermis and makes its way towards the spongocoel lined with choanocytes. The water is filtered and exits the sponge through the osculum.

Question 20

Syconoid canal system

Answer 20

Water enters the sponge through a large number of Ostia into an incurrent canal then passes through prosopyles into the radial canals, where food is ingested by choanocytes. The flagella of the choanocytes moves water to the spongocoel. Filtered water exits through the osculum.

Question 21

Leuconoid sponges

Answer 21

most common and most complex, Leuconoids generally forms large masses, each member having its own osculum.

Question 22

Calcera

Answer 22

Vase-shaped, small marine sponges with spicules.

Question 23

Demospongiae

Answer 23

the largest class of sponges. Have brilliant colors with monotetraxonal or tetraxonal siliceous spicules. Leuconoid canal system.

Question 24

Hexactinellinda

Answer 24

called “glass sponge” because of six rayed siliceous spicules. Primarily deep water marine forms. Can be simple syconoid or leuconoid.

Question 25

Phylum Cnidaria

Answer 25

named after cnidoblasts that contain stinging cells, or nematocysts.
25. Dimorphism - the cnidarians ability to exhibit two different body forms.

Question 26

Medusa

Answer 26

a form cnidarians exhibit that resembles an upside-down cup with tentacles.

Question 27

Polyp

Answer 27

a form that consists of a tubular sessile body.

Question 28

Mesoglea

Answer 28

gelatinous nonliving substance that exists between the epidermis and the gastrodermis, or endodermis.

Question 29

Budding

Answer 29

a form of asexual reproduction that can be carried out by cnidarians.