Chapter 26: The Tree of Life: REVIEW

1) The first genetic material was most likely a(n)

2) Which gas was probably least abundant in Earth's early atmosphere?

3) In their laboratory simulations of the early Earth, Miller and Urey observed the abiotic synthesis of

4) Which putative early Earth condition did Miller and Urey's experimental apparatus not attempt to simulate directly?

5) Which of the factors below weaken the hypothesis of abiotic synthesis of organic monomers in early Earth's atmosphere?

1. the relatively short time between intense meteor bombardment and appearance of the first life forms

2. the lack of experimental evidence that organic monomers can form by abiotic synthesis

3. uncertainty about which gases comprised early Earth's atmosphere

6) The early atmosphere of Earth probably retained all of the following molecules in substantial amounts except

7) Which of the following has not yet been synthesized in laboratory experiments studying the origin of life?

8) In what way were conditions on Earth more than 2 billion years ago different from those on Earth today?

9) What condition would have made the primitive atmosphere of Earth more conducive to the origin of life than the present one? The primitive atmosphere

10) What is true of the amino acids delivered to Earth within carbonaceous chondrites?

11) Which of the following is the correct sequence of these events in the origin of life?

I. Formation of protobionts

II. Synthesis of organic monomers

III. Synthesis of organic polymers

12) What characteristic would all protobionts have had in common?

13) Although absolute distinctions between the "most evolved" protobiont and the first living cell are unclear, biologists generally agree that one major difference is that protobionts could not

14) Which of the following statements about the origin of genetic material is most probably correct? The first genes were

15) RNA molecules can be both self-replicating and catalytic. This probably means that

16) What probably accounts for the switch to DNA-based genetic systems during the evolution of life on Earth?

17) The synthesis of new DNA requires the prior existence of oligonucleotides to serve as primers. On Earth, these primers are small RNA molecules. This latter observation is evidence in support of the hypothesized existence of

18) How could RNA have become involved in the mechanism for protein translation?

19) If the half-life of carbon-14 is about 5,730 years, then a fossil that has one-eighth the normal proportion of carbon-14 to carbon-12 is probably ________ years old.

20) Which measurement would help determine absolute dates by radiometric means?

21) How many half-lives should have elapsed if 12.5% of the parent isotope remains in a fossil at the time of analysis?

22) Approximately how far back in time does the fossil record extend?

23) What was the consequence of the release of oxygen gas by plant and bacterial photosynthesis?

24) Arrange these events from earliest to most recent.

1. emission of lava in what is now Siberia at time of Permian extinctions

2. emission of lava that solidified at the same time as iron-bearing terrestrial rocks began to rust

3. emission of lava that solidified at the same time as the first banded iron formations formed

4. emission of lava in what is now India at time of Cretaceous extinctions

25) The ancestors of which free-living cells were the earliest autotrophs to contribute to the formation of Earth's oxidizing atmosphere?

26) Elemental sulfur is to hydrogen-sulfide-splitting prokaryotes as ________ is to water-splitting prokaryotes.

27) All are true of the photosynthetic machinery of cyanobacteria, except

28) At the time when Earth's atmosphere was becoming increasingly oxidizing, which reaction could have helped to prevent damage to oxygen-sensitive enzymes and structures. In which prokaryotes might such a reaction have been expected to occur? (Note: these reactions are not balanced.)

29) Which of the following statements provides the strongest evidence that prokaryotes evolved before eukaryotes?

30) How would the chief hypothesis concerning the origin of the ER and Golgi apparatus be described?

31) Which is an actual observation that provides the strongest evidence for the possible origin of the eukaryotic cytoskeleton?

32) Certain protists, namely the parabasalids and diplomonads, have tiny mitochondrial "remnants" that lack DNA. Where, in these organisms, would one look if one were trying to confirm the hypothesis that the lack of mitochondrial DNA is due to horizontal gene transfer?

33) The photosystems of cyanobacteria are embedded in plasma membranes and, in some cases, in internal membranes derived from the plasma membrane. Where would one expect to find the homologous photosystems in green plant cells?

34) The ATP synthase of most mitochondria

35) The hypothesis of "genetic annealing" is used to account for the origin of

36) Which process is most directly associated with genetic annealing?

37) Which genetic process requires one cell or structure to lose genetic material to another cell or structure to which it was not previously genetically identical?

1. binary fission

2. mitosis

3. bacterial conjugation

4. horizontal gene transfer

38) What is the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth?

1. origin of mitochondria

2. origin of multicellular eukaryotes

3. origin of chloroplasts

4. origin of cyanobacteria

5. origin of fungal-plant symbioses

39) Recent evidence indicates that the first major diversification of multicellular eukaryotes may have coincided in time with the

40) Which event may be associated in time with the end of the period known as snowball Earth?

41) Assuming total ice cover, which of these would have been the most likely location for the oxygenic photosynthesizers to have survived snowball Earth?

42) In order for a beneficial mutation to be transmitted across generations, the mutation must occur in

43) The snowball Earth hypothesis provides a possible explanation for the

44) If two continental land masses converge and are united during continental drift, then the collision should bring about

45) A major evolutionary episode that corresponded in time most closely with the formation of Pangaea was the

46) What kind of evidence has recently made it necessary to assign the prokaryotes to either of two different domains, rather than assigning all prokaryotes to the same kingdom?

47) What important criterion was used in the late 1960s to distinguish between the three multicellular eukaryotic kingdoms of the five-kingdom classification system?

48) As the number of kingdoms increased from two to three, what was true of the kingdom Protista?

49) The best classification system is that which most closely

The questions below refer to the following list, which uses the five-kingdom classification system.

1. Plantae

2. Fungi

3. Animalia

4. Protista

5. Monera

50) Which obsolete kingdom includes prokaryotic organisms?

51) Members of which kingdom have cell walls and are all heterotrophic?

52) Which kingdom has been replaced with two domains?

53) Which eukaryotic kingdom is polyphyletic and therefore not acceptable, based on cladistics?

54) Which kingdoms include free-living photosynthetic organisms?

Match the scientists below with their accomplishments.

A. Carl Woese

B. Cech and Altman

C. Oparin and Haldane

D. Miller and Urey

E. Robert Whittaker

55) discovered ribozymes

56) used SSU-rRNA sequences to propose major modifications to the "tree of life"

57) synthesized organic monomers in an apparatus designed to simulate early Earth's conditions

58) proposed the five-kingdom classification system

59) early proponent(s) of the idea that a reducing atmosphere and energy inputs might have been sufficient to introduce organic monomers to Earth's environment

60) The first prokaryotic cells appeared during the

61) Most modern animal phyla evolved during the ________ era.

62) Which of these events occurred earliest in the history of Earth?

63) Which of these events occurred during the Paleozoic?

64) In the two-kingdom system, why were fungi classified in the kingdom Plantae?