BIO 19 (1)

One scientific hypothesis about the origin of life holds that RNA replaced DNA as the most stable information-storing molecule. RNA nucleotides were formed from simple organic molecules in an abiotic stew. proteins that duplicate themselves came to function in information storage. as cells evolved, RNA came to direct protein synthesis.

RNA nucleotides were formed from simple organic molecules in an abiotic stew.

What prevents organic molecules from forming on their own and remaining intact today? Earth is too hot. Atmospheric oxygen is too reactive. The necessary building blocks no longer exist. There is no energy source available.

Atmospheric oxygen is too reactive.

What must be true about an index fossil whose absolute age is used as a reference for other fossils? The absolute age of the index fossil is actually unknown. The absolute age of the index fossil was determined only by relative dating. The absolute age of the index fossil was determined by radioactive dating or another absolute method. The index fossils must be the same age as the other fossils.

The absolute age of the index fossil was determined by radioactive dating or another absolute method.

What does fossil evidence indicate about the order in which these three vertebrates evolved: a bony fish with a jaw, a jawless fish, and a fish with leglike fins? The bony fish evolved before the jawless fish. The fish with leglike fins was the last to evolve. The jawless fish was the last to evolve. The fish with leglike fins evolved before the jawless fish.

The fish with leglike fins was the last to evolve.

Which of these facts about mitochondria and chloroplasts constitute(s) support for the endosymbiotic theory? Their DNA resembles bacterial RNA. Their ribosomes resemble the ribosomes of bacteria. Like bacteria, they reproduce by mitosis. all of the above

Their ribosomes resemble the ribosomes of bacteria.

What do proteinoid microspheres have in common with cells? They can store and release energy. They contain DNA. They contain RNA. They are communities of organisms.

They can store and release energy.

Earth's most recent era is the Paleozoic. Mesozoic. Cenozoic. Precambrian.

Cenozoic.

Which of these labels for fossils in a museum display contains an error? Dinosaur (Middle Mesozoic) Early Mammal (Middle Paleozoic) Early Human (Late Cenozoic) Early Marine Invertebrate (Early Paleozoic)

Early Mammal (Middle Paleozoic)

How would you date a sample of rock that you suspect as being one of the earliest on Earth? Use a radioactive isotope with a short half-life. Use a radioactive isotope with a long half-life. Use an index fossil. Use a microfossil.

Use a radioactive isotope with a long half-life.

Why did oceans not exist on Earth nearly 4 billion years ago? No water molecules were present. Water remained a gas because Earth was very hot. Water existed as ice because Earth was very cold. There was no oxygen gas in the atmosphere.

Water remained a gas because Earth was very hot.

To formulate a hypothesis about how Earth's elements were rearranged after melting, scientists considered which physical principle? Denser materials tended to float on less dense materials. Less dense materials tended to float on denser materials. The most dense materials formed the atmosphere. The least dense materials formed Earth's core.

Less dense materials tended to float on denser materials.

A very large mass extinction in which amphibians and trilobites disappeared occurred at the end of the Precambrian. Cambrian Period. Paleozoic Era. Quaternary Period.

Paleozoic Era.

A single species that has evolved into several different forms that live in different ways has undergone adaptive radiation. coevolution. punctuated equilibrium. mass extinction.

adaptive radiation.

The Mesozoic Era occurred before Precambrian Time. during Precambrian Time. after the Paleozoic Era. after the Cenozoic Era.

after the Paleozoic Era.

Examples of fossils include preserved eggs. footprints. body parts. all of the above

all of the above

The fossil record shows that most organisms that ever lived on Earth are now extinct. fossils occur in a particular order. modern organisms have unicellular ancestors. all of the above

all of the above

What was the response of the various groups of early organisms that existed when oxygen levels rose in the atmosphere? Some life forms became extinct. Some life forms survived only in a few airless habitats. Some life forms evolved metabolic pathways that used oxygen for respiration. all of the above

all of the above

Which of the following functions can RNA perform under certain conditions? catalyzing chemical reactions processing messenger RNA after transcription helping DNA replicate all of the above

all of the above

Which of the following was NOT characteristic of Earth before the oceans formed? volcanic activity bombardment by comets and asteroids an atmosphere of poisonous gases an atmosphere containing oxygen gas

an atmosphere containing oxygen gas

The first organisms on Earth were most like today's bacteria. eukaryotes. multicellular organisms. DNA molecules.

bacteria.

In the past, mass extinctions encouraged the rapid evolution of surviving species by changing developmental genes. by making new habitats available to them. because they killed all organisms that had coevolved. because they spared all organisms that had evolved convergently.

by making new habitats available to them.

The process by which two species, for example, a flower and a pollinating insect, evolve in response to changes in each other over time is called convergent evolution. adaptive radiation. coevolution. punctuated equilibrium.

coevolution.

The endosymbiotic theory proposes that eukaryotic cells arose from individual prokaryotic cells. multicellular prokaryotes. communities formed by prokaryotes. communities formed by eukaryotes.

communities formed by prokaryotes.

Early in Earth's history, while the planet was in a melted state, the most dense elements formed Earth's core. seas. crust. atmosphere.

core.

During the Jurassic and Cretaceous periods, the dominant land animals were amphibians. dinosaurs. grazing mammals. human ancestors.

dinosaurs.

A fossilized dinosaur, found with fossils of the flowering plants that it ate, must have lived since life first evolved. before the Mesozoic Era. during the Mesozoic Era. after the Mesozoic Era.

during the Mesozoic Era.

After Precambrian Time, the basic divisions of the geologic time scale, from larger to smaller are eras and periods. periods and eras. relative and absolute dates. billions of years and millions of years.

eras and periods.

The length of time required for half of the radioactive atoms in a sample to decay is its half-life. relative date. radioactive date. period.

half-life.

Proteinoid microspheres are tiny bubbles that resemble cells because they contain DNA and/or RNA. have selectively permeable membranes. build proteins from amino acids. add oxygen gas to the atmosphere.

have selectively permeable membranes.

Two gases that probably existed in Earth's early atmosphere are oxygen and water vapor. water vapor and nitrogen. oxygen and carbon monoxide. hydrogen cyanide and carbon monoxide.

hydrogen cyanide and carbon monoxide.

To compare the relative ages of fossils, scientists sometimes use an easily recognized species called a(an) carbon fossil. radioactive fossil. index fossil. sedimentary fossil.

index fossil.

In addition to hydrogen, the gases used in Miller and Urey's experiment were nitrogen and oxygen. hydrogen cyanide and oxygen. methane and ammonia. carbon dioxide and hydrogen sulfide.

methane and ammonia.

What proportion of all species that have ever lived has become extinct? less than 1 percent approximately one-half more than 99 percent 100 percent

more than 99 percent

Fossilized evidence of Earth's first forms of life would consist of vertebrates from the Precambrian. invertebrates from the Precambrian. eukaryotes from the Precambrian. prokaryotes from the Precambrian.

prokaryotes from the Precambrian.

A pattern in which species experience long, stable periods interrupted by brief periods of rapid evolutionary change is called convergent evolution. coevolution. adaptive radiation. punctuated equilibrium.

punctuated equilibrium.

The Cambrian Explosion resulted in the evolution of the first dinosaurs and mammals. representatives of most animal phyla. bacteria. land animals.

representatives of most animal phyla.

When oxygen was first released in the early seas, it combined with iron to form RNA. DNA. proteins. rust.

rust.

Most fossils form in rusty water. volcanic rock. sedimentary rock. the sap of ancient trees.

sedimentary rock.

To be useful as an index fossil, a species must have existed for a long period over a wide geographic range. long period over a small geographic range. short period over a wide geographic range. short period over a small geographic range.

short period over a wide geographic range.

Sedimentary rock is formed from the soft parts of organisms. the hard parts of organisms. small particles of sand, silt, and clay. wood, shell, and bone.

small particles of sand, silt, and clay.

Modern experiments similar to Miller and Urey's demonstrate that simulating conditions thought to exist on early Earth can produce some bases contained in RNA. DNA molecules. living things composed of cells. proteins that can catalyze complex chemical reactions.

some bases contained in RNA.

Which of the following conditions would likely prevent the assembly and survival of new kinds of organic molecules on Earth today? the presence of carbon dioxide the presence of bacteria and other life forms the supply of atoms that serve as raw material the light and warmth from the sun

the presence of bacteria and other life forms

One necessary condition for the evolution of the first life on Earth was the presence of DNA. abundant oxygen in the atmosphere. the presence of photosynthetic organisms. the presence of liquid water.

the presence of liquid water.

One way master control genes, or hox genes, could have affected evolution is by causing mutations in other genes. through small changes in timing during embryonic development. through the coevolution of species. by leading to convergent evolution.

through small changes in timing during embryonic development.

Miller and Urey's experiments attempted to demonstrate how Earth first formed. whether DNA or RNA evolved first. whether organic molecules could have formed before life was present. how the deepest part of Earth formed.

whether organic molecules could have formed before life was present.