Chapter 15: Marine Animals

Question 1

what were the first form of primary producers?

Answer 1

probably an early form of cyanobacteria

Question 2

what were the first animal-like creatures?

Answer 2

single-celled organisms

Question 3

what happened during the oxygen revolution?

Answer 3

the activity of photosynthetic autotrophs changed the composition of the atmosphere from less than 1% free oxygen to its present oxygen-rich mixture of more than 20%

Question 4

what is an animal?

Answer 4

a multicellular organism unable to synthesize its own food and often capable of movement

Question 5

what is a phylum?

Answer 5

a group of animals that shares similar architecture, level of complexity, and evolutionary history

Question 6

more than __ of all living and fossil animals including all of the earliest multicellular animals are categorized as invertebrates

Answer 6

90%

Question 7

what are invertebrates?

Answer 7

generally soft-bodied animals that lack a rigid internal skeleton for the attachment of muscles
many possess some sort of hard, protective outer covering

Question 8

what are the most primitive true animals?

Answer 8

sponges (Porifera)

Question 9

what are the few basic shapes of sponges?

Answer 9

branching, vaselike, encrusting

Question 10

what do suspension feeders do?

Answer 10

strain plankton and tiny organic food particles from the surrounding water

Question 11

what organism belongs in the phylum Porifera?

Answer 11

sponges

Question 12

what organisms belong in the phylum Cnidaria?

Answer 12

jellyfish, sea anemones, and corals

Question 13

cnidarians exhibit ____ symmetry

Answer 13

radial

Question 14

what is radial symmetry?

Answer 14

when body parts radiate from a central axis like the spokes of a wheel

Question 15

what are hermatypic corals?

Answer 15

corals that contain masses of symbiotic dinoflagellates

Question 16

what are ahermatypic corals?

Answer 16

corals that lack interior dinoflagellates

Question 17

what is bilateral symmetry?

Answer 17

the body has a left side and a right side that are mirror images of each another

Question 18

the worm body plan exhibits a ____ symmetry

Answer 18

bilateral

Question 19

what are the most primitive organisms with a central nervous system?

Answer 19

flatworms

Question 20

what are the first animals with a flow-through digestive system?

Answer 20

Nematoda

Question 21

what are the most successful of the worm phyla in every imaginable terrestrial, aquatic, and marine habitat?

Answer 21

roundworms

Question 22

what are the most evolutionarily advanced worms?

Answer 22

Annelida

Question 23

what is metamerism?

Answer 23

a convenient strategy for increasing the size of an animal simply by adding nearly identical units

Question 24

what animals are part of the Gastropoda class of mollusc?

Answer 24

snails

Question 25

what animals are part of the Bivalvia class of mollusc?

Answer 25

clams, oysters, and mussels

Question 26

what animals are the part of the Cephalopoda class of mollusc?

Answer 26

nautiluses, octopuses, cuttlefish, and squid

Question 27

what animals are part of the phylum Arthropoda?

Answer 27

lobsters, shrimp, crabs, krill, and barnacles

Question 28

what are 3 evolutionary advances that have led to Arthropods great success?

Answer 28

exoskeleton, striated muscle, articulation

Question 29

what is an Arthropods exoskeleton made of?

Answer 29

chitin

Question 30

what is a water-vascular system?

Answer 30

a complex of water-filled canals, valves, and projections used for locomotion and feeding

Question 31

what is the most structurally complex animal phylum?

Answer 31

Chordata