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oxygen (O2)

Which of the following was probably not present in large amounts in the atmosphere at the time life is thought to have originated? (ebook Major Episodes in the History of Life)

Spontaneous generation

is a theory that states that life arises from nonliving matter

formation of organic monomers

is thought to have been the first step in the origin of life?


The early atmosphere on Earth is thought to have had very little, if any,

H2O, CH4, H2, and NH3

In their experiment on the origin of organic compounds, which of the following gases did Urey and Miller use to simulate Earth's early atmosphere?

The Urey and Miller experiments (and subsequent, similar experiments) showed that

simple organic molecules can form spontaneously under conditions like those thought to prevail early in Earth's history

Clay particles may have played an important role in the origin of life because

clay particles are a suitable surface for the formation of polymers from monomers


It has been suggested that the first self-replicating molecules were

The earliest cells were most likely


The most abundant group of organisms on Earth is the



Prokaryotes called _____ are similar in many ways to eukaryotic organisms.

A streptobacillus kind of prokaryote

consists of rod-shaped cells arranged in chains

chemoheterotrophic prokaryotes

In an experiment, a microbiologist put equal numbers of each of the following organisms into a flask of sterile broth consisting mostly of sugar and a few amino acids. She then placed the flask in the dark. Which of the organisms would be best able to survive?


Prokaryotes that use light for their energy source and CO2 for their carbon source are called

extreme halophiles

Prokaryotes found inhabiting the Great Salt Lake would be the


Methanogens, extreme halophiles, and extreme thermophiles are examples of

a halophile

Which of the following would most likely spoil salted fish?

produce endospores

The bacteria that cause tetanus can be killed only by prolonged heating at temperatures considerably above boiling. This suggests that tetanus bacteria

food poisoning

is a human disease caused by a bacterium


You have been asked to participate in the cleanup of an old mining site. You dislike the idea of handling poisonous acidic soils, so you volunteer to culture the bacterium Thiobacillus. The aspect of the cleanup that you are participating in is

binary fission

Prokaryotes copy themselves and divide in a process known as

mitochondria and chloroplasts

Which of the following organelles were likely generated through endosymbiosis?

Eukaryotic cells probably arose through

associations between different prokaryotes


Protists are a diverse group of organisms that includes

In general, how do algae and protozoans differ?

Algae are photosynthetic, and almost all protozoans are heterotrophic.


Which of these groups includes parasitic unicellular organisms with a complex of organelles specialized for penetrating host cells and tissues?

watch how it moves

A student is looking at a protozoan under the microscope. "I know it's supposed to be a ciliate, a flagellate, or an amoeba, but how am I supposed to know which it is?" she complains to her lab partner. "Easy," her partner says. "Just


Consider the following kinds of organisms: dinoflagellates and ciliates. Both of these organisms belong to which one of the following groups?

the following are protozoans

apicomplexans, flagellates, amoebas, and ciliates


The cells of cellular slime molds bear a resemblance to _____ cells

This mass of cytoplasm is undivided by membranes and contains many nuclei; therefore, it is not technically multicellular

In lab class a plasmodial slime mold is used as a demonstration organism. One of the students does not understand why the plasmodium is not considered multicellular. How would you explain it to her?


are capable of producing a "red tide

green algae

The algal groups most commonly found in freshwater ecosystems are


these groups includes unicellular organisms with unique overlapping cell walls

multicellular green algae

the following groups of algae are most closely related to higher plants


Groups of seaweeds can generally be distinguished on the basis of


he following colonial organisms demonstrate the evolutionary link between unicellular and multicellular life

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