Biology Test Your Knowledge Exam 4

Vertebrate embryos have structures called pharyngeal pouches. What do these structures develop into in an adult human? In an adult bony fish?

middle ear bones in humans; gills in adult bony fish

Put the following terms in order from most inclusive (1) to least inclusive (5). _________ Domain _________ Species _________ Kingdom _________ Genus _________ Phylum

(1) domain (2) kingdom (3) phylum (4) genus (5) species

Place the following evolutionary milestones in order from earliest (1) to most recent (7), providing approximate dates to support your answer. _________ The first multicellular eukaryotes _________ The first prokaryotes _________ The Permian extinction _________ The Cambrian explosion _________ The first animals _________ The extinction of dinosaurs _________ An increase in oxygen in the atmosphere

(1) the first prokaryotes (~3 billion years ago) (2) an increase of oxygen in the atmosphere (~2.5 billion years ago) (3) the first multicellular eukaryotes (~1.2 billion years ago) (4) the Cambrian explosion (~545 million years ago) (5) the first animals (~540 million years ago) (6) the Permian extinction (~248 million years ago) (7) the extinction of dinosaurs (~65 million years ago)

You are examining a column of soil that contains vertebrate fossils from deeper to shallower layers. Would you expect a fossil with four limbs with digits to occur higher or lower in the soil column relative to a "standard" fish? Explain your answer.

A fossil with four limbs and digits would be the fossil of a more recent organism than a "standard" fish. Thus, the "standard" fish fossil would be in deeper layers, and the four-limbed fossil would be in layers above that fish fossil.

What type of seed plant is likely to rely on hungry animals to spread its seeds? Explain your answer.

An angiosperm: its seeds are enclosed in a fruit, which can be a tasty treat for a hungry animal.

You and a fisher are both mammals; as such, what are some characteristics you and the fisher have in common?

As mammals, both fishers and humans have backbones, mammary glands and body hair.

If, in humans, the DNA sequence TTTCTAGGAATA encodes the amino acid sequence phenylalanine-leucine-glycine-isoleucine, what amino acid sequence will that same DNA sequence specify in bacteria?

As the genetic code is universal (with only a few exceptions), the same DNA sequence will encode the same amino acid sequence in both humans and bacteria.

Could you use the presence of a tail to distinguish a human embryo from a chicken embryo? Why or why not?

At early stages of development, both human and chicken embryos have a tail, so this feature will not allow you to distinguish between an early human embryo and an early chicken embryo.

In what sense do bacteria "evolve faster" than other species?

Because bacteria divide very rapidly, they have a very short generation time. As evolution is a change in allele frequency over time, it doesn't take long for bacterial populations to accumulate many generations.

What are the defining features of eukaryotes, members of the domain Eukarya?

Eukaryotes are defined by having cells with membrane-bound organelles, including a nucleus.

What is the evolutionary meaning of the term "fitness"?

Fitness, in an evolutionary context, describes the ability of an individual to survive and reproduce in a given environment. Individuals that are more fit leave more offspring and more of their alleles in the next generation relative to individuals that are less fit.

If penguins and polar bears had evolved before Pangaea split into northern and southern continents, what might you predict about their geographic distribution today?

If they had evolved while Pangaea was still intact, then both polar bears and penguins would have been found across Pangaea, and when Pangaea split both would have migrated to the northern and southern polar regions, and both polar bears and penguins would be found at both poles.

What is the difference between an S. aureus colonization and an S. aureus infection?

In colonization, the bacteria are growing on or in the body without causing disease. Infections are associated with disease.

Why is inbreeding detrimental to a population?

Inbreeding can result in matings between relatives that produce offspring with two (detrimental) recessive alleles. Over time, inbreeding reduces the frequency of heterozygotes, and produces homozygotes that have two deleterious alleles.

Tiktaalik fossils have both fishlike and tetrapod-like characteristics. Which characteristics are related to supporting the body out of the water?

Long and sturdy ribs (to help support the body) and pectoral fins that have wrists and can bear weight.

If two organisms strongly resemble each other in their physical traits, can you necessarily conclude that they are closely related? Explain your answer.

No. While they may be closely related, they may also represent convergent evolution, in which unrelated groups of organisms share common characteristics because of independent natural selection in similar environments.

How did the evolution of vascular systems in plants change the landscape?

Once vascular plants evolved in plants, plants were able to grow taller and live in a variety of habitats, not just in damp places. Plants are present in almost every landscape and are important in characterizing different habitats.

What is an advantage of having seeds? (Think about spreading to new locations and whether or not reproduction relies on water.)

Seeds contain plant embryos in a protective coating. Seeds enable plants to survive temporarily harsh conditions and because they spread relatively easily, can spread plants to new locations.

A young athlete has a nasty skin infection caused by MRSA. How might this infection have been contracted?

The athlete could have been exposed by direct skin contact with another athlete who has MRSA, or by coming into contact with a contaminated item (e.g., towels, shared sports equipment), particularly if the contact occurs at sites where the skin is broken, as by a scrape or cut.

Which group of plants was the first to live on land? Why do we find these plants only in particular environments (after all, if they were first, shouldn't they have spread everywhere by now)?

The bryophytes were the first plants to live on land. As they do not have a vascular system to transport water throughout their bodies, they live in damp environments. They do not have adaptations that would enable them to live in other, drier environments.

You have molecular evidence that leads you to hypothesize that a particular group of soft-bodied sea cucumbers evolved at a certain time. You have found a fossil bed with many hard-shelled mollusks dating to the critical time, but no fossil evidence to support your hypothesis about the sea cucumbers. Does this find cause you to reject your hypothesis? Why or why not?

The hypothesis should not be rejected because of the absence of sea cucumber fossils from the fossil bed. Soft-bodied organisms (such as sea cucumbers) do not fossilize well, and so do not leave fossils in the fossil record.

Compare and contrast the structure and function of an eagle wing with the structure and function of a human arm.

The skeletal anatomy of a chicken wing and that of a human arm are very similar. All major bones are present in each, and in the same locations relative to other bones. In the human, the most distal bones (the tips of the digits) are longer and arranged in a way that permits fine manipulation of objects with hands and fingers. Birds do not need to carry out this fine-scale manipulation, and their wings are specialized for flying.

How does the physical landscape diversity of Olympic National Park affect biodiversity in the park?

There are a variety of habitats in the park, including freshwater lakes and streams, marine environments at the ocean coastline, glacier-topped mountains, and temperate rain forest. A wide variety of organisms with different adaptations for these different habitats can live in the park.

A cactus called ocotillo (Fouquieria splendens), which grows in New Mexico, looks very much like Alluaudia procera, a species of plant that grows in the deserts of Madagascar. These two plant species are not closely related—they are in different orders in the kingdom Plantae. Why then do they look so alike?

These two plant species may look alike because of convergent evolution; both have adapted to a desert climate.

What do uranium-238, carbon-14, and potassium-40 have in common?

They are all radioactive isotopes that decay into other elements at constant rates.

What do a fisher and a fir tree have in common?

They are both eukaryotic and live in Olympic National Park.

Tiktaalik fossils are described as "intermediate" or "transitional" fossils. What does this mean? Why are transitional organisms so significant in the history of life?

Transitional fossils are "intermediate" in that they are midpoints between two groups of organisms. They are important because they shed light on how groups of organisms were able to move into new habitats or develop new structures. Titkaalik represents the transition between aquatic bony fishes and land-dwelling tetrapods.

How does geographic isolation contribute to speciation?

When populations are geographically isolated, they do not exchange alleles. This means that if a mutation arises in one population and not the other, the mutation will be present in only one of the two populations.

To date what you suspect to be the very earliest life on Earth, which isotope would you use: uranium-238, carbon-14, or potassium-40? Explain your answer.

You would use uranium-238, which has the longest half-life of the three (4.5 billion years). Isotopes with shorter half-lives may no longer be present in very ancient sample, having completely decayed.

The term "MRSA" as it is used today refers to: a. S. aureus bacteria that are resistant to many antibiotics. b. a collection of skin and other infections caused by a type of bacteria. c. S. aureus bacteria that are found only in humans with certain types of skin infections. d. S. aureus bacteria that are normal residents of human skin in the vast majority of the human population. e. all bacteria that are resistant to antibiotics.

a. S. aureus bacteria that are resistant to many antibiotics.

The evolution of antibiotic resistance is an example of: a. directional selection. b. diversifying selection. c. stabilizing selection. d. random selection. e. steady selection.

a. directional selection.

Consider the "eating habits" of fungi. a. Can fungi carry out photosynthesis? b. Can fungi ingest their food? c. How do fungi obtain their nutrients and energy?

a: Fungi are not photosynthetic; they are heterotrophs. b: They do not ingest their food. c: They obtain nutrients and energy by secreting digestive enzymes onto their food. The food is then digested into smaller subunits, which are then absorbed by the fungi.

What do all members of the informal group known as protists have in common? a. nothing b. They are all eukaryotic. c. They all carry out photosynthesis. d. They are all human parasites. e. They are all decomposers.

b. They are all eukaryotic.

A sensitive S. aureus bacterium acquires a new gene that allows it to resist the effects of beta-lactam antibiotics (that is, the bacterium is now resistant). What might the protein encoded by that gene do? a. synthesize beta-lactam antibiotics b. digest beta-lactam antibiotics c. produce a toxin d. enhance colonization of human skin e. enhance entry into the bloodstream

b. digest beta-lactam antibiotics

A sand dollar gets its name from its body shape-it resembles a large coin. What type of body symmetry does a sand dollar have? a. bilateral b. radial c. none (sand dollars are amorphous) d. hyphae e. mycelium

b. radial

What do a backbone and an exoskeleton have in common? a. They are found in closely related groups of animals. b. They are made of the same substance. c. They both help provide support to an animal's body. d. They both require an animal to molt in order to be able to grow. e. all of the above

c. They both help provide support to an animal's body.

Which of the following meals include fungi as food? a. a bread and blue cheese platter with fruit b. mushroom risotto c. a and b d. a fruit salad e. yogurt

c. a and b

Which of the following features of Tiktaalik is not shared with other bony fishes? a. scales b. teeth c. a mobile neck d. fins e. none of the above

c. a mobile neck

A bottleneck is best described as a. an expansion of a population from a small group of founders. b. a small number of individuals leaving a population. c. a reduction in the size of an original population followed by an expansion in size as the surviving members reproduce. d. the mixing and mingling of alleles by mating between members of different populations. e. an example of natural selection.

c. a reduction in the size of an original population followed by an expansion in size as the surviving members reproduce.

Which of the following is most likely to leave a fossil? a. a jellyfish b. a worm c. a wolf d. a sea sponge (an organism that lacks a skeleton) e. All of the above are equally likely to leave a fossil.

c. a wolf

What are the two major mechanisms by which bacterial populations generate genetic diversity? a. mutation and meiosis b. binary fission and evolution by natural selection c. gene transfer and mutation d. mutation and binary fission e. gene transfer and replication

c. gene transfer and mutation

MRSA is most likely to be problematic if found: a. on the surface of the skin. b. in nasal passages. c. in the bloodstream. d. on the fingernails. e. The presence of MRSA in any of those locations indicates a serious infection.

c. in the bloodstream

If we take the most fit bacterium from one environment—one in which the antibiotic amoxicillin is abundant, for example—and place it in an environment in which a different antibiotic is abundant, will it retain its high degree of fitness? a. yes; fitness is fitness, regardless of the environment b. yes; once a bacterium is resistant to one antibiotic it is resistant to all antibiotics c. not necessarily; fitness depends on the ability of an organism to survive and reproduce, and it may not do this as well in a different environment d. no; what is fit in one environment will never be fit in another environment

c. not necessarily; fitness depends on the ability of an organism to survive and reproduce, and it may not do this as well in a different environment

In humans, very-large-birth-weight babies and very tiny babies do not survive as well as midrange babies. What kind of selection is acting on human birth weight? a. directional selection b. diversifying selection c. stabilizing selection d. random selection e. steady selection

c. stabilizing selection

Which of the following statement(s) is/are true about both cockroaches and lobsters? a. They are invertebrate insects with bilateral symmetry. b. They are mollusks with an exoskeleton. c. They are arthropods with segmented bodies and no symmetry. d. They are arthropods with an exoskeleton. e. They are mollusks with a segmented body.

d. They are arthropods with an exoskeleton.

Which of the following are examples of genetic drift? a. founder effect b. bottleneck effect c. inbreeding d. a and b e. a, b, and c

d. a and b

A phylogenetic tree represents a. a grouping of organisms on the basis of their shared structural features. b. a grouping of organisms on the basis of their cell type. c. a grouping of organisms on the basis of their complexity. d. a grouping of organisms on the basis of their evolutionary history. e. a grouping of organisms on the basis of where they are found.

d. a grouping of organisms on the basis of their evolutionary history.

How do beta-lactam antibiotics kill sensitive bacteria? a. by attracting water into cells b. by destabilizing the cell membrane c. by preventing DNA replication during bacterial reproduction d. by destabilizing the cell wall e. all of the above, depending on the specific strain of bacteria

d. by destabilizing the cell wall

The biological species concept defines a species a. on the basis of similar physical appearance. b. on the basis of close genetic relationships. c. on the basis of similar levels of genetic diversity. d. on the basis of the ability to mate and produce fertile offspring. e. on the basis of recognizing one another's mating behaviors.

d. on the basis of the ability to mate and produce fertile offspring.

A major difference between a fern and a moss is a. the presence of seeds. b. the presence of flowers. c. the presence of cones. d. the presence of a vascular system. e. the ability to carry out photosynthesis.

d. the presence of a vascular system.

What is the environmental pressure in the case of antibiotic resistance? a. the growth rate of the bacteria b. how strong or weak the bacterial cell walls are c. the relative fitness of different bacteria d. the presence or absence of antibiotics in the environment e. the temperature of the environment

d. the presence or absence of antibiotics in the environment

Can S. aureus be present in or on a person who has no evidence of an infection? a. no; S. aureus is associated only with infections b. yes, but only non-MRSA strains are present in the absence of an infection c. yes, but only for very short periods of time (between touching a contaminated surface and washing your hands) d. yes; S. aureus is a common skin bacterium e. yes; S. aureus is a common bacterium found in the bloodstream

d. yes; S. aureus is a common skin bacterium

Which of the following statements is/are true about a nonevolving population? a. Allele frequencies do not change over generations. b. Genotype frequencies do not change over time. c. Individuals choose mates with whom they share many alleles. d. all of the above e. a and b

e. a and b

Which of the following is not a domain of life? a. Animalia b. Eukarya c. Bacteria d. Archaea e. Plantae f. Neither a nor e is a domain of life.

f. Neither a nor e is a domain of life.