Chapter 34 Reading Quiz

1. The deuterostome branch has two modern phyla: the chordates & the ____________.

2. List the four anatomical features that characterize the Phylum Chordata. (4 point question)

1. Describe the four unique characteristics of chordates.

1. Notochord flexible rod located between the gut and nerve cord

2. Dorsal hollow nerve cord where the brain & spinal cord develop

3. Pharyngeal slits similar to gills, allows water through mouth to exit before digestive system

4. Muscular postanal tail

2. Distinguish between the three subphyla of the phylum Chordata and give

examples of each.

1. Urochordata tunicates- are filter feeders and sessile

2. Cephalochordata lancelets- all 4 characteristics persist into adulthood

3. Vertebrates any animal with a backbone- have a greater degree of cephalization

3. Describe the specialized characteristics found in the subphylum Vertebrata and

explain how each is beneficial to survival.

1. Neural crest helps with formation of certain skeletal components

2. Cephalization sensory organs on anterior end for quicker processing

3. Vertebral column support and strong anchor – basic skeleton

4. Closed circulatory system heart, arteries, capillaries, veins

4. Compare and contrast members of Agnatha, Placadermi, and

Chondrichthyes.

• Agnatha jawless fishes (400-500 mya)- lampreys, hagfishes, about 60 species

• Placadermi now extinct, has paired fins and hinged jaws

• Chondrichthyes 750 species- sharks, skates, and rays- skeletons of cartilage, well-developed jaws, paired fins, lateral line system- sexual reproduction with internal fertilization

5. Explain how members of the class Osteichthyes have become so diversified.

• 30,000 species• They spread from freshwater to

marine and back at some point• Swim bladders• Maneuverable swimmers1. Lobe-finned2. Lungfishes3. Ray-finned fishes

6. Summarize the evidence supporting the fact that amphibians evolved from

crossopterygians.

• Evolved from lobe-finned fishes (skeletal structure)

• Anatomical similarities• Molecular data suggests close relation

to lungfishes

7. Distinguish between the three orders of living amphibians.

1. Urodela salamanders, 400 species2. Anura frogs and toads, 3500 species3. Apoda caecilians (legless & blind),

150 species

8. List the distinguishing characteristics of members of the class Reptilia and explain any special adaptations to the terrestrial

environment. • Scales prevent desiccation & dehydration• Gas exchange via lungs• Dioecious with sexual reproduction and internal

fertilization- most are oviparous and produce an amniotic egg

• Ectotherms use behavioral adaptations to absorb solar energy and regulate body temperature - can survive on less than 10% calories of that of mammals

9. Explain how environmental changes during the Cretaceous Period may have

affected the dinosaurs.

• The climate became cooler and more variable and mass extinctions occurred

• A few survived into the early Cenozoic, but all these reptiles were gone by the end of the Cretaceous (65 mya)

10. List the distinguishing characteristics of members of the class Aves and explain

any special adaptations for flight.

Each part of bird anatomy is modified in some way that enhances flight

• Bones with honeycombed internal structure

• No teeth, a gizzard• Endothermic and insulated (feathers)• 4 chambered heart with efficient lungs• Well-developed nervous system• Dioecious with sexual reproduction and

internal fertilization

11. Summarize the evidence supporting the fact that birds evolved from reptilian

ancestors.

• Possess distinct reptilian characteristics such as the amniotic egg and scales on legs

• Common ancestor Archaeopteryx lithographica - clawed forelimbs, teeth, long tail, feathers- not considered direct ancestor to modern birds but a side branch

• Birds arose from a theropod ancestor

12. Explain why mammals underwent an adaptive radiation during the Cenozoic.

• 4500 species • The extinction of the dinosaurs and

fragmentation of continents opened new adaptive zones at the end of the Mesozoic era

13. Distinguish between monotreme, marsupial, and placental mammals.

• Monotreme egg laying, hair, milk- found in Australia- Ex: platypus, spiny echidna

• Marsupials young are born early and finish development in pouch, attached to teat- mostly Australia- Ex: kangaroos, opossum, koala

• Placental uterus, placenta, live birth- also called “eutherian”

14. Explain how convergent evolution produced marsupial and placental

ecological counterparts on different continents.

• Marsupials and placentals diverged from a common ancestor about 80 – 100 mya

• Adaptive radiation during the late Cretaceous and early Tertiary periods (70 – 45 mya) produced the orders of extant placental mammals

15. Compare and contrast the four main evolutionary lines of placental mammals.

1. Chiroptera & Insectivora bats and shrews, modified forelimbs

2. Lagomorpha, Perissodactyla, Artiodactyla, Sirenia, Proboscidea- rabbits, odd-toed and even-toed ungulates, sea cows (manatees), and elephants- medium herbivores

3. Carnivora cats, dogs, sea lions, etc4. Primates & Rodentia rats,

squirrels, beavers; monkeys, apes, humans

16. Describe the characteristics found in early primates which indicate an arboreal

(tree-living) existence.

1. Limber shoulder joints which allow swinging2. Dexterous hands for hanging and

manipulating food3. Sensitive fingers with nails, not claws4. Eyes close together for good depth

perception (to swing)5. Excellent hand-eye coordination6. Parental care with usual single births and

long nurturing of offspring

17. Appraise the significance of the three most prominent misconceptions about

human evolution. 1. Our ancestors were chimpanzees or other modern

apesactual: they represent 2 divergent branches of the anthropoid lineage evolved from a common, less specialized ancestor

2. Human evolution represents a ladder with a series of steps leading directly from an ancestral anthropoid to Homo sapiensactual: progressively have become more modern, many branches and dead ends along the way

3. Various human characteristics like posture and brain evolved in unisonactual: mosaic evolution different things evolved at different times

18. Diagram and evolutionary tree for humans.

• First of all: it is uncertain• Humans and apes diverged 6 – 8 mya from a

common African anthropoid1. Australopithecus africanus erect, teeth & hands

like ours, 1/3 the brain, about 3 – 4 mya2. Australopithecus afarensis “Lucy”, 1m tall, upright 3. A. anamensis 4. A. ramidus5. Homo habilis coexisted with Australopithecus6. H. erectus 1.8 mya – 250,000; taller, larger brain,

Neanderthals7. H. sapiens out of Africa

19. Explain how humans have influenced the extinction rates of other organisms.

• Humans are the most numerous and widespread of the large animals rate of extinctions this century is 50x greater than the average for the past 100,000 years due mostly to habitat destruction, chemical pollution, overpopulation temperature increase, alteration of world climate, fossil fuel consumption especially rain forests (effect on species & world)

• Homo sapiens may be the most devastating crisis in the history of life