Deck 6: The Origin and Evolution of Life on Earth

Question 1

If a fossil were to be discovered which was 3.7 billion years old this would tell us that life on Earth must have arisen

A) exactly 3.7 billion years ago
B) at least 3.7 billion years ago
C) less than 3.7 billion years ago
D) much later than 3.7 billion years ago

Answer 1

at least 3.7 billion years ago

Question 2

The first life to originate on Earth must be

A) at least as old as the oldest fossils
B) exactly the same age as the oldest fossils
C) younger than the oldest fossils
D) much older than the oldest fossils

Answer 2

at least as old as the oldest fossils

Question 3

Carbon isotope evidence from rocks found on an island off the coast of Greenland, although controversial, suggests that life may have

A) existed and was well established by3.4 to 3.5 billion years ago
B) originated about 3.4 billion years ago
C) existed 3.85 billion years ago
D) originated when the Earth formed 4.6 billion years ago

Answer 3

existed 3.85 billion years ago

Question 4

Microfossils found in northwestern Australia in 2011 appears to have used compounds based on which element for metabolism?

A) sulfur
B) oxygen
C) nitrogen
D) carbon

Question 5

Microfossil evidence suggests that life

A) originated when the Earth formed 4.6 billion years ago
B) originated about 3.4 billion years ago
C) existed 3.85 billion years ago
D) existed and was well established by 3.4 to 3.5 billion years ago

Question 6

Currently, the strongest evidence for microfossils dates to approximately

A) 4.0 billion years ago
B) 3.5 billion years ago
C) 3.4 billion years ago
D) 3.9 billion years ago

Question 7

Microfossils are

A) fossilized microbes
B) the remains of very small dinosaurs
C) the remains of the very first multicellular organisms
D) the remains of the tiny organisms which were first to colonize onto land

Question 8

Which approach is currently proving to be the most promising way of determining how life on Earth originated?

A) studies of Martian meteorites
B) studies of organisms living around deep-sea ocean vents
C) studies of the fossil record
D) laboratory simulations of conditions present on the early Earth

Question 9

Stromatolites date back to approximately

A) 4.6 billion years ago
B) 3.5 billion years ago
C) 3.85 billion years ago
D) 4.0 billion years ago

Question 10

Microfossils found in northwestern Australia in 2011 appear to have been

A) photoheterotrophs
B) chemoheterotrophs
C) photoautotrophs
D) chemoautotrophs

Question 11

Why have studies of the geological record not enabled us to determine how life on Earth originated?

A) the first living organisms would have left absolutely no trace of their existence
B) life was planted on the Earth by an advanced civilization so there is no evidence in the geological record to find
C) the geological record does not extend back to the time that life originated
D) the oldest rocks are too deep inside the Earth for us to retrieve

Question 12

Why is the claim of the discovery of microfossils controversial?

A) they are found in rocks from the Hadean Eon
B) it is not clear whether they are of biological or mineral origin
C) the rocks they are found in are probably contaminated by terrestrial bacteria
D) they are too small to be of biological origin

Question 13

Stromatolites are

A) fossils of the first organisms to introduce oxygen into the atmosphere
B) fossils of the first multicellular organisms
C) layers of sediment that once contained colonies of ancient microbes
D) fossils of the first eukaryotes

Question 14

Organisms close to each other on the "Tree of Life"

A) are genetically very different
B) look very similar to the eye
C) are genetically identical
D) are genetically very similar

Question 15

Modern day living stromatolites which resemble ancient stromatolites very closely have been found in

A) the Yucatan peninsula, Mexico
B) South West Greenland
C) Western Australia
D) Yellowstone National Park, U.S.A.

Question 16

Why can studies of carbon isotopes be used to detect the presence of past biological activity in rocks?

A) living organisms absorb only the most common carbon isotope
B) living organisms remove all carbon from rocks
C) living organisms absorb certain carbon isotopes more easily than others
D) carbon isotopes are found only in living organisms

Question 17

A sample of an ancient sedimentary rock contains slightly less of the isotope carbon-13 than found in inorganic material. One possible explanation for this is that

A) it was a meteorite that fell from the sky
B) some kind of radioactive decay occurred in it in the past
C) it used to be at the bottom of an ancient ocean
D) some kind of biological activity occurred in it in the past

Question 18

Current geological evidence suggests that life

A) took billions of years to appear
B) appeared as soon as the Earth formed
C) appeared quite early in Earth's history
D) appeared relatively recently in Earth's history

Question 19

Where in the "Tree of Life" will current organisms be located that are most closely related to the common ancestor of all life on Earth?

A) at the branch between animals and plants
B) very close to the root
C) at the branch between Archaea and Eukarya
D) very far from the root

Question 20

The rocks found in Greenland with carbon isotope ratios suggestive of life are

A) igneous
B) sedimentary
C) metamorphic
D) a mixture of sedimentary and metamorphic

Question 21

Organisms far from each other on the "Tree of Life"

A) are genetically very similar
B) are genetically very different
C) look very similar to the eye
D) are genetically identical

Question 22

Current evidence suggests that life on Earth

A) originated in shallow ponds on land
B) was delivered from elsewhere in meteorites
C) was deliberately planted by an advanced civilization
D) originated close to deep-sea volcanic vents or underground

Question 23

In order for organic molecules to have formed on the early Earth, what do we know could not have been present in the atmosphere in significant quantities?

A) oxygen (O₂)
B) nitrogen (N₂)
C) carbon dioxide (CO₂)
D) argon (Ar)

Question 24

In the original Miller-Urey experiment it was assumed that carbon and nitrogen in the early atmosphere were present as

A) carbon dioxide (CO₂) and nitrogen (N₂)
B) carbonates (CO₃⁻) and nitrates (NO₃⁻)
C) methane (CH₄) and ammonia (NH₃)
D) carbon and nitrogen atoms

Question 25

What is the "chicken-and-egg" type problem we face when trying to decide which came first-proteins or nucleic acids?

A) proteins and nucleic acids probably looked very different before the origin of life
B) nucleic acids cannot replicate without proteins, and proteins cannot be made without nucleic acids
C) early proteins and nucleic acids were very similar to each other
D) proteins and nucleic acids are always present together at the same time

Question 26

Which of the following was an important source of prebiotic molecules (e.g., amino acids) on the early Earth?

A) molecules produced on the surface by impacts
B) molecules produced by chemical reactions near deep-sea ocean vents
C) molecules transported to the surface by impacts
D) all of these

Question 27

The first self-replicating molecule was probably

A) a simple carbohydrate
B) DNA
C) a simple protein
D) RNA

Question 28

Under what conditions will prebiotic molecules NOT be manufactured in Miller-Urey experiments?

A) if ammonia (NH₃) is present in the flask
B) if methane (CH₄) is present in the flask
C) if oxygen (O₂) is present in the flask
D) if carbon dioxide (CO₂) is present in the flask

Question 29

Why do we think that DNA was probably NOT the first self-replicating molecule?

A) it is able to replicate using carbohydrates rather than proteins
B) it is far to complex to have been the first self-replicating molecule
C) it is able to replicate at high temperatures found near deep ocean vents
D) laboratory have shown that it is able to catalyze its own replication

Question 30

Why do we think that RNA was probably the first self-replicating molecule?

A) it is able to replicate at high temperatures found near deep-sea ocean vents
B) it is much simpler than DNA
C) in laboratory studies researchers have shown that it is able to catalyze its own replication
D) it is able to replicate using carbohydrates rather than proteins

Question 31

As life on Earth evolved, its DNA

A) changed gradually into RNA
B) stayed the same
C) became gradually less complex
D) became gradually more complex

Question 32

Why are clay surfaces good at promoting the formation of biological polymers?

A) they are the only types of material monomers will stick to
B) they bring monomers close together, allowing them to react with each other
C) they are very common on the Earth
D) clays are made of biological polymers

Question 33

RNA catalysts in cells are referred to as

A) enzymes
B) ribozymes
C) ribosomes
D) chemzymes

Question 34

What is one reason that early life formed cells?

A) cell walls prevent heat from escaping
B) cells concentrate molecules together so they react more easily
C) only cells can replicate
D) biological reactions can occur only within cells

Question 35

In modern Miller-Urey experiments it is assumed that carbon and nitrogen in the early atmosphere were present as

A) methane (CH₄) and ammonia (NH₃)
B) carbon dioxide (CO₂) and nitrogen (N₂)
C) carbonates (CO₃⁻) and nitrates (NO₃⁻)
D) carbon and nitrogen atoms

Question 36

In 2014, when scientists used a laser to simulate the conditions generated when a large impact hits a mixture of prebiotic molecules, they were able to produce

A) all 20 amino acids used in life
B) all four DNA bases used in life
C) complex carbohydrates
D) simple proteins

Question 37

The first molecules of RNA were probably made

A) on the surfaces of clays or other minerals
B) deep within the earth
C) in the atmosphere
D) in space and then transported to the Earth in meteorites

Question 38

In the 19ᵗʰ century, Charles Darwin suggested that life may have originated

A) in shallow ponds on land
B) deep beneath the oceans
C) beneath the surface of the Earth
D) in the atmosphere

Question 39

Life probably did not originate on the land surface because

A) impacts would have destroyed any life that appeared
B) water was not plentiful on land
C) there was no ozone layer to shield out harmful UV rays
D) organic materials were not present on the land

Question 40

The transition from chemistry to biology occurred

A) gradually in a number of distinct steps
B) very quickly in in one single step
C) very quickly in a number of distinct steps
D) gradually in one single step

Question 41

To date, meteorites have been identified originating from which planets and moons?

A) Mars only
B) All terrestrial planets
C) The Moon and Mars
D) The Moon only

Question 42

If we eventually find life on Mars, we could tell if panspermia may have occurred between Mars and Earth if

A) the biochemistry of Martian life is very different than life on Earth
B) the biochemistry of Martian life is very similar to life on Earth
C) Martian life shows evidence for natural selection
D) Martian life is cellular

Question 43

The very first living organisms on the Earth were probably

A) chemoheterotrophs
B) photoautotrophs
C) photoheterotrophs
D) chemoautotrophs

Question 44

The first living organisms interacted with the atmosphere

A) sexually
B) symbiotically
C) aerobically
D) anaerobically

Question 45

The possibility of life being transferred from another planet like Mars largely depends on whether that life can survive

A) being lasted from the parent planet
B) inside the meteorite with very little water present
C) long enough in space to make the journey to Earth
D) the impact onto the Earth's surface

Question 46

What was one reason that RNA was eventually replaced by DNA as the molecule of choice for storing genetic information?

A) the bases that make up DNA became much more common
B) DNA is far more stable than RNA
C) DNA can catalyze its own replication
D) the double helix of DNA is better able to correct errors in replication

Question 47

Based on current scientific evidence, the theory that has been most successful at explaining the origin of life on Earth is

A) naturism
B) panspermia
C) intelligent design
D) chemical evolution

Question 48

One type of early protocell (pre-cells) probably consisted of small droplets of

A) water
B) clay
C) lipids
D) nucleic acids

Question 49

Why is the chemical evolution model preferred by scientists over other theories for the origin of life on Earth?

A) it is the theory that best fits the available data
B) because we have been able to create Life in the laboratory
C) because it was written down in ancient scriptures
D) because the other theories have been shown to be incorrect

Question 50

One type of early protocell (pre-cells) probably consisted of small droplets of

A) water
B) clay
C) concentrated amino acids
D) nucleic acids

Question 51

One theory for the origin of life suggests that life formed spontaneously from increasingly complex chemical reactions on the Earth. This is referred to as

A) intelligent design
B) naturism
C) panspermia
D) chemical evolution

Question 52

For microbes to survive the journey in a meteorite from another solar system body to the Earth they would have to survive the

A) impact that blasted the rock off of the surface of its home world
B) high energy particles and radiation in space
C) entry through our atmosphere
D) all of these

Question 53

One theory for the origin of life suggests that the earth and Life were created by some omnipotent being. This is referred to as

A) panspermia
B) intelligent design
C) naturism
D) chemical evolution

Question 54

The first living organisms probably resembled

A) single-celled eukaryotes
B) multicellular eukaryotes
C) single-celled prokaryotes
D) multicellular prokaryotes

Question 55

Most meteorites from the inner solar system originate from

A) the Moon
B) Mars
C) Mercury
D) Venus

Question 56

One theory for the origin of life suggests that life was transported to Earth in meteorites. This is referred to as

A) naturism
B) intelligent design
C) panspermia
D) chemical evolution

Question 57

What is one reason that early life formed cells?

A) only cells can replicate
B) cell walls prevent heat from escaping
C) cells help to protect fragile biological molecules from the outside environment
D) biological reactions can occur only within cells

Question 58

Based on current scientific evidence, what is the likelihood that life on Earth was transported to Earth in meteorites?

A) impossible
B) very likely
C) certain
D) possible

Question 59

Based on current scientific evidence, what is the likelihood that life on Earth formed spontaneously from increasingly complex chemical reactions?

A) very likely
B) certain
C) impossible
D) very unlikely

Question 60

Based on current scientific evidence, what is the likelihood that life on Earth was created by some omnipotent being?

A) very unlikely but not impossible
B) impossible
C) certain
D) very likely

Question 61

The relationship between organelles and their host cells can best be described as

A) viral
B) sexual
C) symbiotic
D) parasitic

Question 62

The "oxygen crisis" occurred around

A) 2 billion years ago
B) 3.5 billion years ago
C) 2.5 billion years ago
D) 4 billion years ago

Question 63

The colonization of land by plants appears to have begun about

A) 542 million years ago
B) 360 million years ago
C) 65 million years ago
D) 475 million years ago

Question 64

Plants and animals belong to the phylum

A) annelida
B) echinodemata
C) cnidaria
D) chordata

Question 65

What happened at the start of the Cambrian Period?

A) the first oxygen-producing bacteria appeared
B) the first dinosaurs appeared
C) early humans first appeared
D) an explosion of genetic diversity appeared, leading to the appearance of the first animals

Question 66

Compared to life today the rate of diversification in early organism was probably

A) exactly the same as it is today
B) much slower than it is today
C) much faster than it is today
D) just slightly slower than it is today

Question 67

The first living organisms to develop photosynthesis were probably

A) purple and green sulfur bacteria
B) trilobites
C) cyanobacteria
D) stromatolites

Question 68

An explosion of genetic diversity similar to that which occurred during the Cambrian Period hasn't happened recently, most likely because

A) evolution of life on Earth is no longer occurring
B) such an explosion can occur only for simple organisms and not complex ones
C) there are no more ecological niches available to allow this to happen
D) of the widespread presence of efficient predators that make it much more difficult for entirely new organisms to appear

Question 69

The colonization of life onto land was closely tied to the

A) appearance of multicellular organisms
B) development of photosynthesis
C) oceans being overcrowded
D) development of the ozone layer

Question 70

The first multicellular organism appears around

A) 542 million years ago
B) 1.2 billion years ago
C) 65 million years ago
D) 3.5 billion years ago

Question 71

All multicellular organisms are

A) Bacteria
B) Prokaryotes
C) Archaea
D) Eukarya

Question 72

The highest level of classification of plants and animals is a

A) kingdom
B) phylum
C) class
D) order

Question 73

What is one piece of evidence that some organelles like mitochondria and chloroplasts within eukaryotes used to be independent prokaryotes that were incorporated into eukaryotic cells?

A) prokaryotes are seen incorporating into cells today
B) organelles float around independently inside eukaryotic cells
C) the DNA inside organelles is not made of the same four bases as the DNA in the host cells
D) they have their own DNA and reproduce independently of the host cell

Question 74

The first eukarya appeared

A) 4.6 billion years ago
B) around 3.5 billion years ago
C) 4.0 billion years ago
D) at least 2.1 billion years ago or perhaps even earlier

Question 75

Today, which organisms have the highest biomass?

A) fungi
B) plants
C) animals
D) microbes

Question 76

What do we mean by "The Oxygen Crisis" in relation to the evolution of life on Earth?

A) the extinction of older anaerobic life as oxygen builds up in the atmosphere
B) the time period before the development of the ozone layer
C) a period when evolution accelerated so rapidly that there was insufficient oxygen available
D) the destruction of oxygen in the early atmosphere

Question 77

The Cambrian Explosion began approximately

A) 2.1 billion years ago
B) 542 million years ago
C) 1.2 billion years ago
D) 65 million years ago

Question 78

Aerobic organisms first started building up oxygen in the Earth's atmosphere around

A) 4.6 billion years ago
B) 3.5 billion years ago
C) 4.0 billion years ago
D) 2.5 billion years ago

Question 79

Why do we believe the Cambrian explosion occurred so suddenly?

A) oxygen concentrations reached critical levels necessary to support more complex life
B) organisms became sufficiently complex that more diversity became possible
C) climate change due the end of the last snowball Earth phase
D) all of these

Question 80

What is one piece of evidence that some organelles like mitochondria and chloroplasts within eukaryotes used to be independent prokaryotes that were incorporated into eukaryotic cells?

A) the DNA inside organelles is not made of the same four bases as the DNA in the host cells
B) organelles float around independently inside eukaryotic cells
C) prokaryotes are seen incorporating into cells today
D) organelles are very similar to present-day bacteria, suggesting a common ancestor