Question 1

Given Earth's evolutionary timeline, what percent of Earth-like planets in a 2 billion-year-old star cluster can be estimated to host intelligent life?

Accepted Answer

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

Question 2

Which of the following occurred approximately 500 million years ago?

Accepted Answer

A)  the extinction of the dinosaurs 
B)  the Cambrian explosion 
C)  the formation of the Moon 
D)  the rise of mammals 
E)  the birth of the first humans 
A)  the extinction of the dinosaurs 
B)  the Cambrian explosion 
C)  the formation of the Moon 
D)  the rise of mammals 
E)  the birth of the first humans

Question 3

Carbon forms the backbone of our complex DNA structure primarily because

Accepted Answer

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 other atoms at a time. 
E)  it can form multiple types of crystal structures. 
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 other atoms at a time. 
E)  it can form multiple types of crystal structures.

Question 4

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

Accepted Answer

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

Question 5

Why is the factor L in the Drake equation important to the final result, and why is it difficult to determine a reasonable estimate for this number?

Accepted Answer

The factor L is the average length that

Question 6

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

Accepted Answer

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

Question 7

Exponential growth generally describes a population

Accepted Answer

A)  that has a constant rate of growth. 
B)  that doubles in size in an infinitesimally small fraction of a second. 
C)  that has virtually an infinite space available for growth. 
D)  that is not undergoing natural selection. 
E)  of silicon-based molecular structures. 
A)  that has a constant rate of growth. 
B)  that doubles in size in an infinitesimally small fraction of a second. 
C)  that has virtually an infinite space available for growth. 
D)  that is not undergoing natural selection. 
E)  of silicon-based molecular structures.

Question 8

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

Accepted Answer

A)  stromatolites 
B)  fish colonies 
C)  eukaryotes 
D)  meteorites 
E)  fungi 
A)  stromatolites 
B)  fish colonies 
C)  eukaryotes 
D)  meteorites 
E)  fungi

Question 9

If future exploration of the moons of Jupiter and Saturn discover primitive life-forms, it would imply a ________ probability of finding an advanced civilization somewhere else in the Milky
Way because ________.

Accepted Answer

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

Question 10

The most immediate threat to all life on Earth is/are

Accepted Answer

A)  the lifetime of the Sun. 
B)  human factors (war, pollution, etc.). 
C)  the eventually collision between the Milky Way and Andromeda galaxies. 
D)  the tidal effects of Jupiter. 
E)  geological activity (volcanoes, plate tectonics, etc.). 
A)  the lifetime of the Sun. 
B)  human factors (war, pollution, etc.). 
C)  the eventually collision between the Milky Way and Andromeda galaxies. 
D)  the tidal effects of Jupiter. 
E)  geological activity (volcanoes, plate tectonics, etc.).

Question 11

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

Accepted Answer

This image shows the Urey-Miller experim

Question 12

If DNA contains only five different chemical elements, how do we explain the diversity of life-forms on Earth?

Accepted Answer

The atoms form the basic structures of D

Question 13

Imagine that you built a time machine and successfully traveled 2 billion years back in time. What would you observe, given our current understanding of Earth's history?

Accepted Answer

A)  dinosaurs roaming Earth 
B)  forests and insects everywhere on Earth 
C)  the ongoing heavy bombardment of Earth 
D)  a severe scarcity of oxygen in the atmosphere 
E)  You would be floating in space because Earth hadn't formed yet. 
A)  dinosaurs roaming Earth 
B)  forests and insects everywhere on Earth 
C)  the ongoing heavy bombardment of Earth 
D)  a severe scarcity of oxygen in the atmosphere 
E)  You would be floating in space because Earth hadn't formed yet.

Question 14

What was the goal of the Urey-Miller experiment schematized in the figure below?

Accepted Answer

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 
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 15

Why are radio waves considered to be the best part of the spectrum to deliver and search for signals to and from extraterrestrial intelligent life-forms?

Accepted Answer

Radio waves easily penetrate the dust an

Question 16

If we discovered life on another body within our own Solar System, how would this change our perspective on life elsewhere in the universe?

Accepted Answer

The discovery of even primitive life-for

Question 17

What is the so-called Fermi paradox?

Accepted Answer

The Fermi paradox essentially summarizes

Question 18

What does "habitable zone around a star" mean in the current framework of the search for exoplanets?

Accepted Answer

A)  the region around the star where the inhabitants of nearby planetary systems can safely visit 
B)  the region around the star where planetary temperatures would not be too hot or too cold for liquid water to exist 
C)  the region around the star where planets have icy moons 
D)  the region around the star where planets can form an atmosphere 
E)  the region around the star where intelligent civilizations are not exposed to harmful doses of radiation 
A)  the region around the star where the inhabitants of nearby planetary systems can safely visit 
B)  the region around the star where planetary temperatures would not be too hot or too cold for liquid water to exist 
C)  the region around the star where planets have icy moons 
D)  the region around the star where planets can form an atmosphere 
E)  the region around the star where intelligent civilizations are not exposed to harmful doses of radiation

Question 19

What would be the main advantages and disadvantages of silicon-based chemistry for alien life-forms?

Accepted Answer

Silicon,just like carbon,could have four

Question 20

Which of the following Solar System objects is LEAST likely to have, or have had, life?

Accepted Answer

A)  Mars 
B)  Jupiter's moon Europa 
C)  Saturn's moon Titan 
D)  Venus 
E)  Saturn's moon Enceladus 
A)  Mars 
B)  Jupiter's moon Europa 
C)  Saturn's moon Titan 
D)  Venus 
E)  Saturn's moon Enceladus

Exam 24: Life

Given Earth's evolutionary timeline, what percent of Earth-like planets in a 2 billion-year-old star cluster can be estimated to host intelligent life?

Which of the following occurred approximately 500 million years ago?

Carbon forms the backbone of our complex DNA structure primarily because

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

Why is the factor L in the Drake equation important to the final result, and why is it difficult to determine a reasonable estimate for this number?

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

Exponential growth generally describes a population

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

If future exploration of the moons of Jupiter and Saturn discover primitive life-forms, it would imply a ________ probability of finding an advanced civilization somewhere else in the Milky Way because ________.

The most immediate threat to all life on Earth is/are

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

If DNA contains only five different chemical elements, how do we explain the diversity of life-forms on Earth?

Imagine that you built a time machine and successfully traveled 2 billion years back in time. What would you observe, given our current understanding of Earth's history?

What was the goal of the Urey-Miller experiment schematized in the figure below?

Why are radio waves considered to be the best part of the spectrum to deliver and search for signals to and from extraterrestrial intelligent life-forms?

If we discovered life on another body within our own Solar System, how would this change our perspective on life elsewhere in the universe?

What is the so-called Fermi paradox?

What does "habitable zone around a star" mean in the current framework of the search for exoplanets?

What would be the main advantages and disadvantages of silicon-based chemistry for alien life-forms?

Which of the following Solar System objects is LEAST likely to have, or have had, life?

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Formation of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Planetary Moons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

The Interstellar Medium and Star Formation

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

Galaxies

The Milky Waya Normal Spiral Galaxy

The Expanding Universe

Cosmology

Large-Scale Structure in the Universe

Filters

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