Deck 24: Life

Question 1

Some forms of life on Earth are silicon-based.

Answer 1

False

Question 2

Which of the following is a likely source of the energy needed to create the first life on Earth?

A)land volcanoes
B)asteroid impacts
C)lightning
D)fire
E)earthquakes

Answer 2

lightning

Question 3

Terrestrial life utilizes 20 different acids that are composed of only four different chemical elements.

Answer 3

True

Question 4

Why did the presence of cyanobacteria on Earth in the past allow humans to exist?

A)It was the first form of life.
B)It oxygenated the atmosphere.
C)It fertilized the soil to let plants grow.
D)It increased the carbon dioxide in the atmosphere,causing the greenhouse effect.
E)It was the first life form based on DNA.

Question 5

The Drake equation estimates the number of solar systems in our galaxy today that may harbor life.

Question 6

The image below is of an Australian shoreline.Which of the following forms of early life on Earth does it depict?

A)stromatolites
B)cyanobacteria
C)eukaryotes
D)meteorites
E)fungi

Question 7

If we model the history of the universe as a single day,at what time would the first primitive forms of single-celled microorganisms appear?

A)5:00 A.M.
B)9:00 A.M.
C)12:00 noon
D)3:00 P.M.
E)5:20 P.M.

Question 8

The main goal of the Allen Telescope Array is to search for high redshift galaxies.

Question 9

In which of the following locations has life NOT been found on Earth?

A)near deep-oceans hydrothermal vents
B)in extremely dry deserts
C)in Arctic ice
D)in hot sulfur springs
E)None of the above.Life has been found in all of these locations.

Question 10

Approximately 10 percent of all life on Earth has been in the form of microorganisms.

Question 11

What was the goal of the experiment depicted below?

A)to create a microorganism
B)to simulate the formation of Earth
C)to simulate the Big Bang
D)to simulate the early universe
E)to simulate the formation of the building blocks of life

Question 12

The habitable zone for a 1M_⨀ star ranges from 0.7 to 1.4 AU from the star.

Question 13

Which one of the following is NOT one of the three categories of terrestrial life based on their DNA characteristics?

A)bacteria
B)eukarya
C)archaea
D)fungi

Question 14

Where do we think life first formed on the Earth?

A)in the air
B)in the oceans
C)on land
D)on meteoroids that carried microorganisms to Earth
E)deep in the interior of Earth

Question 15

Imagine if you built a time machine and successfully traveled 2 billion years backward in time.What would happen?

A)You would see dinosaurs roaming Earth.
B)You would see numerous multicellular species on Earth.
C)You probably would be killed by the ongoing heavy bombardment of Earth.
D)You would die due to lack of oxygen.
E)You would be floating in space because Earth hadn't formed yet.

Question 16

Scientists have shown that ammonia and methane,mixed together with liquid water and either hydrogen,carbon dioxide,or nitrogen,and exposed to electrical sparks,can produce some of the amino acids essential for life.

Question 17

The four main chemicals of which most life forms on Earth are composed are hydrogen,carbon,oxygen,and calcium.

Question 18

According to the theory of evolution,chemical reactions resulting in the mutation of a molecule are a natural and inevitable occurrence.

Question 19

In 1952,chemists Harold Urey and Stanley Miller mixed ammonia,methane,and hydrogen;in a closed container;zapped it with electrical sparks and found that:

A)they could induce cold fusion to occur
B)they could not induce any amino acids to form
C)single-celled microorganisms had been spontaneously created
D)they had created many of the amino acids contained in DNA
E)they created life in a test tube

Question 20

Mutations always lead to improvements in an organism's ability to survive and reproduce.

Question 21

The ability for one generation to pass on its characteristics to future generations is known as:

A)natural selection
B)mutations
C)heredity
D)self-replication
E)duplication

Question 22

Complex microorganisms that have complex DNA enclosed in a cell nucleus are called:

A)algae
B)bacteria
C)fungi
D)eukaryotes
E)prokaryotes

Question 23

If future exploration of the moons of Jupiter and Saturn discovered primitive life forms,it would ___________ the probability of finding an advanced civilization somewhere else in the Milky Way because ___________.

A)increase;it shows that life can exist in environments which are very different from those found on Earth
B)increase;it would show that life can survive travel through space after leaving the Earth
C)not affect;primitive life forms have nothing to do with the existence of advanced civilizations
D)decrease;it would show that primitive life forms outside the Earth cannot evolve into more complex species
E)decrease;it would show that primitive life forms are far more common than advanced ones

Question 24

Which of these pictures depicts the situation with the lowest entropy?

A)A
B)B
C)C
D)D
E)E

Question 25

Which one of the following is NOT one of the six chemical elements commonly found in living organisms?

A)helium
B)hydrogen
C)oxygen
D)phosphorus
E)nitrogen

Question 26

What is the major difference between prokaryotes and eukaryotes?

A)Eukaryotes have DNA,and prokaryotes have RNA.
B)Eukaryotes have a nuclear membrane surrounding their DNA,and prokaryotes do not.
C)Eukaryotes are planets,and prokaryotes are animals.
D)Eukaryotes appeared on Earth before prokaryotes.
E)Eukaryotes are single-celled,and prokaryotes are multicellular.

Question 27

If a mutation occurred and spawned a population B that had a 25 percent higher chance of reproducing than the original population A,in how many generations would B make up 90 percent of the total population?

A)10
B)16
C)20
D)24
E)32

Question 28

The second law of thermodynamics states that:

A)all systems must become more disordered with time
B)all systems must become more ordered with time
C)some systems can become more ordered if others become less ordered by the same amount or more
D)Earth must revolve around the Sun
E)energy must always be conserved

Question 29

Carbon forms the backbone of our DNA primarily because:

A)it is the most abundant element in the universe after hydrogen and helium
B)it reacts easily with oxygen
C)it remains solid even at high temperatures
D)a carbon atom can bond with up to four atoms at a time
E)it can form multiple types of crystal structures

Question 30

If we model the history of the universe as a single day,at what time would the first Homo sapiens appear?

A)11:59:58.5 P.M.
B)11:59:20 P.M.
C)11:35:00 P.M.
D)10:00 P.M.
E)6:00 P.M.

Question 31

Why could life not have existed on land any earlier than 475 million years ago?

A)The temperature was too high.
B)There was too little sunlight.
C)There was too little oxygen in the atmosphere.
D)Earth was covered in erupting volcanoes.
E)There was no land because Earth was covered in water.

Question 32

If we model the history of the universe as a single day,at what time would the dinosaurs be wiped out by a large asteroid?

A)5:20:00 P.M.
B)11:00:00 P.M.
C)11:35:00 P.M.
D)11:53:10 P.M.
E)11:59:25 P.M.

Question 33

Based on what you know of the Earth's evolution,what percent of Earth-like planets in a star cluster with an age of 2 billion years likely has intelligent life?

A)0
B)10 percent
C)30 percent
D)50 percent
E)100 percent

Question 34

The field of astrobiology uses our knowledge of ___________ to study life in the universe.

A)biology
B)chemistry
C)physics
D)astronomy
E)all of the above

Question 35

Which of these occurred approximately 500 million years ago?

A)the extinction of the dinosaurs
B)the Cambrian explosion
C)The Moon was formed.
D)the rise of mammals
E)the birth of the first humans

Question 36

Which of the following elements are NOT found in DNA molecules?

A)carbon
B)nitrogen
C)hydrogen
D)helium
E)oxygen

Question 37

Which of the following sketches could describe the evolutionary tree of life on Earth? In each diagram,time increases as you move upward,and each branch represents a different species.

A)A
B)B
C)C
D)D
E)E

Question 38

Animals are most closely related to which of the following branches?

A)bacteria
B)archaea
C)flagellates
D)fungi
E)cyanobacteria

Question 39

Why was a comet impact 65 million years ago a chance happening that benefited the evolution of humans?

A)It deposited a significant amount of nitrogen into the Earth's atmosphere.
B)It led to an increase in global UV radiation,which killed off most of the forests and jungles.
C)Mammals got an evolutionary boost.
D)Plant life began to decline.
E)It brought human DNA to Earth.

Question 40

Which of the following Solar System objects is NOT a good candidate for future searches for life?

A)Mars,because it once had liquid water on the surface
B)Jupiter's moon Europa,because it appears to have liquid water under its frozen surface
C)Saturn's moon Titan,because it has an atmosphere containing many organic molecules
D)Pluto,because a large portion of it is made of water ice
E)Saturn's moon Enceladus,because its cryovolcanoes indicate that it has liquid water under the surface

Question 41

SETI's Allen Telescope Array is designed to search ___________ for signs of intelligent life.

A)over a thousand stars
B)over a million stars
C)over a billion stars
D)galaxies in the Local Group
E)the 100 closest spiral galaxies

Question 42

When the Pioneer and Voyager spacecraft were launched into space in the 1970s,they were outfitted with messages describing where they came from.Why is it fairly unlikely that an alien civilization will use them to find us?

A)The extremely large distances between stars means it will take a very long time before they reach another solar system.
B)They will probably rust and fall apart as they get older.
C)They will burn up as the Sun's gravity pulls them in.
D)They will likely run into Kuiper Belt objects before they leave the Solar System.
E)They are moving so fast through space that they would be very difficult to catch.

Question 43

In 1974,astronomers sent a message toward globular cluster M13.If life exists there,and it returns our signal,we won't receive it for at least another 44,000 years.Why?

A)It will take that long for the space probe carrying our signal to reach the life forms there.
B)Based on the age of the stars in M13,we anticipate it would take that long for a civilization to evolve enough to interpret and respond to our signal.
C)M13 is far enough away that even light takes a very long time to reach it.
D)It will take that long before our Solar System and M13 are properly aligned again.
E)The universe will have expanded substantially after M13 receives our message,therefore taking much longer for their response to make it back to Earth.

Question 44

What are the four main elements that make up all living organisms on the Earth?

Question 45

Describe the experiment depicted below.What was the goal of the experiment? Was the experiment a success?

Question 46

Using life on Earth as an example,calculate the maximum likelihood that any technologically advanced civilization that arose still exists on its home planet today.

Question 47

A value of N = 0.1 for the Drake equation signifies that:

A)one out of every 10 solar systems in our galaxy harbors intelligent life
B)one out of every 10 solar systems in our galaxy harbors life of some kind
C)one out of every 10 galaxies in our universe harbors intelligent life
D)one out of every 10 galaxies in our universe harbors life of some kind
E)approximately one intelligent civilization in the universe is created every 10 billion years.

Question 48

We search for intelligent life in the universe most effectively by:

A)sending out spacecraft with messages on them
B)using radio telescopes to search for radio signals
C)monitoring ultraviolet radiation emitted by stars
D)sending spacecraft to explore other worlds
E)all of the above

Question 49

The habitable zone around a star depends most on its:

A)mass and age
B)radius and distance
C)age and radius
D)color and distance
E)luminosity and velocity

Question 50

Based on what we know about the evolution of life on Earth,which of the planets below would be most likely to contain an advanced civilization?

A)Planet A
B)Planet B
C)Planet C
D)Planet D
E)Planet E

Question 51

What determines whether or not a specific mutation is passed on to future generations?

Question 52

If the entire history of the universe were scaled to fit into one day,what time of day would microorganisms first form,oxygen start becoming a significant component of the atmosphere,and humans split off from their genetic ancestors?

Question 53

If the most pessimistic assumptions in the Drake equation were true,we would:

A)have to wait for millions of years to get a message back from the nearest intelligent life
B)have to wait for approximately 40 years to get a message back from the nearest intelligent life
C)be the only intelligent life in the universe
D)need to concentrate on the Andromeda Galaxy when searching for intelligent life
E)need to concentrate on the most distant galaxies to find signs of intelligent life

Question 54

Why would the 21-cm line be a good place to search for signals from intelligent life in the universe?

Question 55

If you wanted to find intelligent life in the universe,what spectral types of stars would you study and why?

Question 56

What is SETI,what is its main objective,and how does it plan to achieve it?

Question 57

As living organisms evolved to become more complex during the history of the Earth,did this violate the second law of thermodynamics?

Question 58

If we wanted to search the Milky Way for other civilizations,where should we look?

A)near high-mass stars,because they live longer
B)near low-mass stars,because their habitable zones are farther from their stars
C)near the galactic center,because the higher temperature makes life more likely
D)in the disk of the Milky Way,because planets there are more protected from harmful gamma rays and X-rays coming from the galactic center
E)in the halo of the Milky Way,because stars in the halo have more heavy elements than stars in the disk

Question 59

People argue against the possibility of time travel by saying,"If humans will eventually be able to travel back in time,then where are all the tourists from the future?" This idea is similar to the ___________,only applied to time travel instead of aliens.

A)Drake equation
B)cosmological principle
C)Fermi paradox
D)Urey-Miller experiment
E)evolutionary tree of life

Question 60

What would be the number of intelligent civilizations in our galaxy if all stars formed planets,each planet has a 0.1 percent change of supporting life,and every time conditions are right life develops,but only 0.001 percent of the time intelligent life develops,and once it develops it survives indefinitely?

Question 61

Name three main dangers (one human and two astrophysical)that threaten the continued existence of human life on Earth.