Chapter 12

Question 1

Phylum Porifera

Answer 1

Simple, multicellular animals forming colonies with bodies perforated by many pores. Sponges.

Question 2

Phylum Archaeocyatha

Answer 2

Extinct, double-walled, vase or cup shaped animals with pores in walls.

Question 3

Phylum Cnidaria

Answer 3

Radially symmetrical animals with stinging cells, including corals, jellyfish and sea anemones.

Question 4

Phylum Bryozoa

Answer 4

Tiny, colonial animals with U-shaped row of tentacles, often building branching colonies.

Question 5

Phylum Brachiopoda

Answer 5

Marine invertebrates with shell composed of two parts (valves), one dorsal and the other ventral.

Question 6

Phylum Arthropoda

Answer 6

Animals with jointed appendages, segmented body, and armor-like exoskeleton.

Question 7

Phylum Mollusca

Answer 7

Unsegmented, mostly shell-bearing invertebrates, including bivalves (clams, oysters), snails, chambered nautilus, and Octopods.

Question 8

Phylum Echinodermata

Answer 8

Spiny-skinned invertebrates with radially symmetrical adult bodies and water vascular system. Starfishes, sea urchins, Crinoids.

Question 9

First vertebrate animals appeared during the…

Answer 9

Paleozoic and as early as the Cambrian.

Question 10

First true mammals appeared during the…

Answer 10

Mesozoic

Question 11

3 mass extinction events throughout the Paleozoic era:

Answer 11

Late Ordovician, Devonian, and Permian periods.

Question 12

Describe small Shelly fossils

Answer 12

First animals to develop “hard parts” throughout the late neoproterozoic and Cambrian.

Question 13

“Cloudina”

Answer 13

An organism that lived from neoproterozoic time into the Cambrian. Secreted a ringed calcareous tube.

Question 14

“Anabarites”

Answer 14

(“Small Shelly fossils”) secreted a phosphate shell that resembles three “tubes” open to one another along the length of the shell. Each tube is surmounted by a narrow keel that may have given the animal stability in sea floor mud.

Question 15

“Aldanella”

Answer 15

(“Small Shelly fossils”) shell secreted by a gastropod (snail).

Question 16

“Lapwortbella”

Answer 16

(“Small Shelly fossils”). Has the shape of a curved cone ornamented with grooved and ridges. It probably was not the single shell of an animal, but one of many similar elements that covered the body.

Question 17

Cambrian explosion

Answer 17

The abrupt appearance of many varied animal about 535 million years ago during the Cambrian.

Question 18

HOX genes

Answer 18

Sequences of genes that control the development of entire regions of the body. Very small changes in HOX genes are potentially able to cause sudden and major evolutionary change.

Question 19

Burgess Shale

Answer 19

Exposure of middle Cambrian Burgess Shale in British Columbia which contains four major groups of Arthropods (trilobites, crustaceans, and members of the taxonomic groups that include scorpions and insects.) as well as sponges, onycophorans, Crinoids, Mollusks, three phyla of worms, corals, chordates, and many species not placed in any known phylum.

Question 20

Phylum Sarcodina

Answer 20

Single called eukaryotes with pseudopodia, including foraminifera and radiolaria.