Paleozoic Life History - The Changing Earth: Exploring Geology and Evolution - page 591

Important Terms

acanthodian (p. 575)
amniote egg (p. 580)
benthos (p. 564)
bony fi sh (p. 577)
carnivore-scavenger (p. 564)
cartilaginous fi sh (p. 576)
chordate (p. 571)
crossopterygian (p. 578)

gymnosperm (p. 587)
herbivore (p. 564)
labyrinthodont (p. 580)
nekton (p. 564)
nonvascular (p. 584)
ostracoderm (p. 574)
pelycosaur (p. 580)
placoderm (p. 576)
plankton (p. 564)

primary producer (p. 564)
protorothyrids (p. 580)
sediment-deposit feeder (p. 564)
seedless vascular plant (p. 585)
suspension feeder (p. 564)
therapsid (p. 581)
vascular (p. 582)
vertebrate (p. 571)

Review Questions

1. The greatest recorded mass extinction to affect Earth
occurred at the end of which period?
a. _____ Cambrian;
b. _____ Ordovician;
c. _____ Devonian;
d. _____ Permian;
e. _____ Cretaceous.
2. The Burgess Shale fauna is signifi cant because it con-
tains the
a. _____ fi rst shelled animals;
b. _____ carbonized impressions of many extinct soft-
bodied animals;
c. _____ fossils of rare marine plants;
d. _____ earliest known benthic community;
e. _____ earliest known fi sh.
3. What type of invertebrates dominated the Ordovician
invertebrate community?
a. _____ epifaunal, benthonic, sessile suspension feeders;
b. _____ infaunal, benthonic, sessile suspension feeders;
c. _____ epifaunal, benthonic, mobile suspension feeders;
d. _____ infaunal, nektonic carnivores;
e. _____ epifl oral, planktonic primary producers.
4. Based on similarity of embryo cell division, which
invertebrate group is most closely allied with the
chordates?
a. _____ molluscs;
b. _____ echinoderms;
c. _____ sponges;
d. _____ worms;
e. _____ arthropods.

d. _____ pelycosaurs;
e. _____ therapsids.
7. Which algal group was the probable ancestor of vascu-
lar plants?
a. _____ yellow;
b. _____ blue-green;
c. _____ red;
d. _____ brown;
e. _____ green.
8. Which evolutionary innovation allowed reptiles to
colonize all of the land?
a. _____ tear ducts;
b. _____ additional bones in the jaw;
c. _____ the middle-ear bone;
d. _____ an egg that contained food and waste sacs and
an embryo surrounded by a fl uid-fi lled sac;
e. _____ limbs and a backbone capable of supporting
the animals on land.
9. The discovery of Tiktaalik roseae is signifi cant because
it is
a. _____ the ancestor of modern reptiles;
b. _____ an intermediary between lobe-fi nned fi sh and
amphibians;
c. _____ the fi rst vascular land plant;
d. _____ the “missing link” between amphibians and
reptiles;
e. _____ the oldest known fi sh.
10. Pelycosaurs are
a. _____ jawless fi sh;
b. _____ jawed, armored fi sh;
c. _____ reptiles;
d. _____ amphibians;
e. _____ plants.
11. Discuss how changing geologic conditions affected the
evolution of invertebrate life during the Paleozoic Era.
12. If the Cambrian explosion of life was partly the result
of fi lling unoccupied niches, why don't we see such
rapid evolution following mass extinctions such as
those that occurred at the end of the Permian and
Cretaceous periods?

5. Organisms living in the water column above the seafl oor are
a. _____ benthic;
b. _____ epifaunal;
c. _____ infaunal;
d. _____ epifl oral;
e. _____ pelagic.

6. Which of the following groups did amphibians evolve from?
a. _____ coelacanths;
b. _____ ray-fi nned fi sh;
c. _____ lobe-fi nned fi sh;