Question 1

Which hypothesis suggests that organic molecules necessary for life may have arrived on Earth via meteorites, and what is a major challenge to this hypothesis?

Accepted Answer

Extraterrestrial hypothesis; destruction of molecules by heat and pressure during impact

Question 2

Which of the following is NOT a bias that affects the fossil record?

Accepted Answer

Organisms living inland are more likely to fossilize than those near water

Question 3

According to radiometric dating, which isotope would be most appropriate for dating a fossil estimated to be 2 billion years old?

Accepted Answer

Potassium-40 ($$^{40}K)$$

Question 4

Which of the following best explains why RNA is hypothesized to have been the first self-replicating molecule in early life?

Accepted Answer

RNA can store information, self-replicate, and catalyze reactions

Question 5

A fossil is found in sedimentary rock and contains 25% of its original radioactive isotope. If the half-life of the isotope is 10,000 years, how old is the fossil?

Accepted Answer

$$20,000$$ years

Question 6

Which environmental change is most directly associated with mass extinctions and subsequent adaptive radiations?

Accepted Answer

Meteoric impacts causing rapid climate shifts

Question 7

Which process is most responsible for the evolution of eukaryotic cells from prokaryotic ancestors?

Accepted Answer

Endosymbiosis between bacterial and archaeal cells

Question 8

Which of the following best describes the sequence of major evolutionary events on Earth?

Accepted Answer

Origin of prokaryotes → origin of eukaryotes → origin of multicellular eukaryotes → colonization of land

Question 9

Which of the following is a plausible explanation for the formation of polymers in prebiotic Earth conditions?

Accepted Answer

Polymerization on clay surfaces or hydrothermal vents

Question 10

Why does the fossil record tend to underestimate the actual time since a species came into existence?

Accepted Answer

Fossilization is more likely for recent and abundant species

Question 11

Which developmental process explains why cetaceans (whales and dolphins) do not develop hind limbs as adults?

Accepted Answer

Spatial variation in expression of developmental genes leading to resorption of hind limb buds

Question 12

Which of the following is NOT a characteristic of protocells?

Accepted Answer

Ability to photosynthesize

Question 13

During which period did the 'Cambrian explosion' occur, and what was its significance?

Accepted Answer

Phanerozoic; rapid increase in animal diversity

Question 14

Which of the following best explains why DNA eventually replaced RNA as the primary information storage molecule in cells?

Accepted Answer

DNA is less likely to suffer mutations and can store information more stably

Question 15

If a fossil contains 12.5% of its original $$^{14}C$$ and the half-life of $$^{14}C is 5730 $$years, how many half-lives have passed and what is the approximate age of the fossil?

Accepted Answer

3 half-lives; $$17,190$$ years

Question 16

Which of the following environmental changes has NOT been a major driver of evolutionary change and extinction events?

Accepted Answer

Seasonal variation in rainfall

Question 17

Which statement about multicellularity is most accurate according to current scientific understanding?

Accepted Answer

Multicellularity likely evolved from unicellular organisms aggregating or daughter cells sticking together

Question 18

Which of the following best describes the role of developmental genes in evolutionary change?

Accepted Answer

They influence cell division, migration, differentiation, and death, affecting organismal phenotypes

Question 19

Which of the following is a direct result of mass extinction events?

Accepted Answer

Adaptive radiation of surviving groups

Question 20

Which of the following is the correct order of appearance on Earth, from earliest to latest?

Accepted Answer

Prokaryotes → Eukaryotes → Multicellular eukaryotes → Animals → Land plants → Humans

Origin and History of Life – General Biology Study Notes

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