Chapter 34 Reading Quiz

1. Chapter 34 Reading Quiz • The deuterostome branch has two modern phyla: the chordates & the ____________. • List the four anatomical features that characterize the Phylum Chordata. (4 point question)

3. 1. Describe the four unique characteristics of chordates. • Notochord  flexible rod located between the gut and nerve cord • Dorsal hollow nerve cord  where the brain & spinal cord develop • Pharyngeal slits  similar to gills, allows water through mouth to exit before digestive system • Muscular postanal tail 

5. 2. Distinguish between the three subphyla of the phylum Chordata and give examples of each. • Urochordata  tunicates - are filter feeders and sessile • Cephalochordata  lancelets - all 4 characteristics persist into adulthood • Vertebrates  any animal with a backbone - have a greater degree of cephalization 

8. 3. Describe the specialized characteristics found in the subphylum Vertebrata and explain how each is beneficial to survival. • Neural crest  helps with formation of certain skeletal components • Cephalization  sensory organs on anterior end for quicker processing • Vertebral column  support and strong anchor – basic skeleton • Closed circulatory system  heart, arteries, capillaries, veins 

10. 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 

12. 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 swimmers • Lobe-finned • Lungfishes • Ray-finned fishes 

14. 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 

15. 7. Distinguish between the three orders of living amphibians. • Urodela  salamanders, 400 species • Anura  frogs and toads, 3500 species • Apoda  caecilians (legless & blind), 150 species 

17. 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 

20. 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) 

21. 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 

23. 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 

26. 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 

27. 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” 

31. 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 

33. 15. Compare and contrast the four main evolutionary lines of placental mammals. • Chiroptera & Insectivora  bats and shrews, modified forelimbs

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

36. Carnivora  cats, dogs, sea lions, etc • Primates & Rodentia  rats, squirrels, beavers; monkeys, apes, humans

37. 16. Describe the characteristics found in early primates which indicate an arboreal (tree-living) existence. • Limber shoulder joints which allow swinging • Dexterous hands for hanging and manipulating food • Sensitive fingers with nails, not claws • Eyes close together for good depth perception (to swing) • Excellent hand-eye coordination • Parental care with usual single births and long nurturing of offspring 

39. 17. Appraise the significance of the three most prominent misconceptions about human evolution. • Our ancestors were chimpanzees or other modern apes actual: they represent 2 divergent branches of the anthropoid lineage evolved from a common, less specialized ancestor • Human evolution represents a ladder with a series of steps leading directly from an ancestral anthropoid to Homo sapiens actual: progressively have become more modern, many branches and dead ends along the way • Various human characteristics like posture and brain evolved in unison actual: mosaic evolution  different things evolved at different times 

41. 18. Diagram and evolutionary tree for humans. • First of all: it is uncertain • Humans and apes diverged 6 – 8 mya from a common African anthropoid • Australopithecus africanus erect, teeth & hands like ours, 1/3 the brain, about 3 – 4 mya • Australopithecus afarensis  “Lucy”, 1m tall, upright • A. anamensis • A. ramidus • Homo habilis  coexisted with Australopithecus • H. erectus  1.8 mya – 250,000; taller, larger brain, Neanderthals • H. sapiens  out of Africa 

44. 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 