Examples of fossils include preserved

1. Examples of fossils include preserved • eggs. • footprints. • body parts. • all of the above

2. Sedimentary rock is formed from • the soft parts of organisms. • the hard parts of organisms. • small particles of sand, silt, and clay. • wood, shell, and bone.

3. What proportion of all species that have ever lived has become extinct? • less than 1 percent • approximately one-half • more than 99 percent • 100 percent

4. Most fossils form in • rusty water. • volcanic rock. • sedimentary rock. • the sap of ancient trees.

5. The fossil record shows that • most organisms that ever lived on Earth are now extinct. • fossils occur in a particular order. • modern organisms have unicellular ancestors. • all of the above

6. To be useful as an index fossil, a species must have existed for a • long period over a wide geographic range. • long period over a small geographic range. • short period over a wide geographic range. • short period over a small geographic range.

7. The length of time required for half of the radioactive atoms in a sample to decay is its • half-life. • relative date. • radioactive date. • period.

8. To compare the relative ages of fossils, scientists sometimes use an easily recognized species called a(an) • carbon fossil. • radioactive fossil. • index fossil. • sedimentary fossil.

9. How would you date a sample of rock that you suspect as being one of the earliest on Earth? • Use a radioactive isotope with a short half-life. • Use a radioactive isotope with a long half-life. • Use an index fossil. • Use a microfossil.

10. What must be true about an index fossil whose absolute age is used as a reference for other fossils? • The absolute age of the index fossil is actually unknown. • The absolute age of the index fossil was determined only by relative dating. • The absolute age of the index fossil was determined by radioactive dating or another absolute method. • The index fossils must be the same age as the other fossils.

11. After Precambrian Time, the basic divisions of the geologic time scale, from larger to smaller are • eras and periods. • periods and eras. • relative and absolute dates. • billions of years and millions of years.

12. The Mesozoic Era occurred • before Precambrian Time. • during Precambrian Time. • after the Paleozoic Era. • after the Cenozoic Era.

13. Earth’s most recent era is the • Paleozoic. • Mesozoic. • Cenozoic. • Precambrian.

14. Fossilized evidence of Earth’s first forms of life would consist of • vertebrates from the Precambrian. • invertebrates from the Precambrian. • eukaryotes from the Precambrian. • prokaryotes from the Precambrian.

15. Which of these labels for fossils in a museum display contains an error? • Dinosaur (Middle Mesozoic) • Early Mammal (Middle Paleozoic) • Early Human (Late Cenozoic) • Early Marine Invertebrate (Early Paleozoic)

16. Why did oceans not exist on Earth nearly 4 billion years ago? • No water molecules were present. • Water remained a gas because Earth was very hot. • Water existed as ice because Earth was very cold. • There was no oxygen gas in the atmosphere.

17. Early in Earth’s history, while the planet was in a melted state, the most dense elements formed Earth’s • core. • seas. • crust. • atmosphere.

18. Which of the following was NOT characteristic of Earth before the oceans formed? • volcanic activity • bombardment by comets and asteroids • an atmosphere of poisonous gases • an atmosphere containing oxygen gas

19. Two gases that probably existed in Earth’s early atmosphere are • oxygen and water vapor. • water vapor and nitrogen. • oxygen and carbon monoxide. • hydrogen cyanide and carbon monoxide.

20. To formulate a hypothesis about how Earth’s elements were rearranged after melting, scientists considered which physical principle? • Denser materials tended to float on less dense materials. • Less dense materials tended to float on denser materials. • The most dense materials formed the atmosphere. • The least dense materials formed Earth’s core.

21. In addition to hydrogen, the gases used in Miller and Urey’s experiment were • nitrogen and oxygen. • hydrogen cyanide and oxygen. • methane and ammonia. • carbon dioxide and hydrogen sulfide.

22. Miller and Urey’s experiments attempted to demonstrate • how Earth first formed. • whether DNA or RNA evolved first. • whether organic molecules could have formed before life was present. • how the deepest part of Earth formed.

23. What prevents organic molecules from forming on their own and remaining intact today? • Earth is too hot. • Atmospheric oxygen is too reactive. • The necessary building blocks no longer exist. • There is no energy source available.

24. Which of the following conditions would likely prevent the assembly and survival of new kinds of organic molecules on Earth today? • the presence of carbon dioxide • the presence of bacteria and other life forms • the supply of atoms that serve as raw material • the light and warmth from the sun

25. Modern experiments similar to Miller and Urey’s demonstrate that simulating conditions thought to exist on early Earth can produce • some bases contained in RNA. • DNA molecules. • living things composed of cells. • proteins that can catalyze complex chemical reactions.

26. One necessary condition for the evolution of the first life on Earth was • the presence of DNA. • abundant oxygen in the atmosphere. • the presence of photosynthetic organisms. • the presence of liquid water.

27. Which of the following functions can RNA perform under certain conditions? • catalyzing chemical reactions • processing messenger RNA after transcription • helping DNA replicate • all of the above

28. What do proteinoid microspheres have in common with cells? • They can store and release energy. • They contain DNA. • They contain RNA. • They are communities of organisms.

29. Proteinoid microspheres are tiny bubbles that resemble cells because they • contain DNA and/or RNA. • have selectively permeable membranes. • build proteins from amino acids. • add oxygen gas to the atmosphere.

30. One scientific hypothesis about the origin of life holds that • RNA replaced DNA as the most stable information-storing molecule. • RNA nucleotides were formed from simple organic molecules in an abiotic stew. • proteins that duplicate themselves came to function in information storage. • as cells evolved, RNA came to direct protein synthesis.

31. The endosymbiotic theory proposes that eukaryotic cells arose from • individual prokaryotic cells. • multicellular prokaryotes. • communities formed by prokaryotes. • communities formed by eukaryotes.

32. What was the response of the various groups of early organisms that existed when oxygen levels rose in the atmosphere? • Some life forms became extinct. • Some life forms survived only in a few airless habitats. • Some life forms evolved metabolic pathways that used oxygen for respiration. • all of the above

33. When oxygen was first released in the early seas, it combined with iron to form • RNA. • DNA. • proteins. • rust.

34. The first organisms on Earth were most like today’s • bacteria. • eukaryotes. • multicellular organisms. • DNA molecules.

35. Which of these facts about mitochondria and chloroplasts constitute(s) support for the endosymbiotic theory? • Their DNA resembles bacterial RNA. • Their ribosomes resemble the ribosomes of bacteria. • Like bacteria, they reproduce by mitosis. • all of the above

36. The Cambrian Explosion resulted in the evolution of the first • dinosaurs and mammals. • representatives of most animal phyla. • bacteria. • land animals.

37. A very large mass extinction in which amphibians and trilobites disappeared occurred at the end of the • Precambrian. • Cambrian Period. • Paleozoic Era. • Quaternary Period.

38. During the Jurassic and Cretaceous periods, the dominant land animals were • amphibians. • dinosaurs. • grazing mammals. • human ancestors.

39. A fossilized dinosaur, found with fossils of the flowering plants that it ate, must have lived • since life first evolved. • before the Mesozoic Era. • during the Mesozoic Era. • after the Mesozoic Era.

40. What does fossil evidence indicate about the order in which these three vertebrates evolved: a bony fish with a jaw, a jawless fish, and a fish with leglike fins? • The bony fish evolved before the jawless fish. • The fish with leglike fins was the last to evolve. • The jawless fish was the last to evolve. • The fish with leglike fins evolved before the jawless fish.

41. The process by which two species, for example, a flower and a pollinating insect, evolve in response to changes in each other over time is called • convergent evolution. • adaptive radiation. • coevolution. • punctuated equilibrium.

42. In the past, mass extinctions encouraged the rapid evolution of surviving species • by changing developmental genes. • by making new habitats available to them. • because they killed all organisms that had coevolved. • because they spared all organisms that had evolved convergently.

43. A single species that has evolved into several different forms that live in different ways has undergone • adaptive radiation. • coevolution. • punctuated equilibrium. • mass extinction.

44. One way master control genes, or hox genes, could have affected evolution is • by causing mutations in other genes. • through small changes in timing during embryonic development. • through the coevolution of species. • by leading to convergent evolution.

45. A pattern in which species experience long, stable periods interrupted by brief periods of rapid evolutionary change is called • convergent evolution. • coevolution. • adaptive radiation. • punctuated equilibrium.

46. The fossil record, although incomplete, provides evidence about the history of life and illustrates that most species have remained unchanged over time. _________________________ • True • False

47. The radioactive isotope most useful for dating fossils less than 60,000 years old is potassium-40. _________________________ • True • False

48. Scientists use geologic dating to determine the absolute age of a rock in years. _________________________ • True • False

49. The vast majority of Earth’s history—about 88 percent—is taken up by the Cenozoic Era. _________________________ • True • False

50. The Cenozoic Era included the Cretaceous, Jurassic, and Triassic Period. _________________________ • True • False