Biology Final

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Exam 1

In the hope of helping clean up creosote-contaminated sediments in the Puget Sound, you genetically engineer a strain of bacteria to include genes involved in the degradation of the polycyclic aromatic hydrocarbon napthalene. Although your strain initially shows only poor growth when given napthalene as a sole carbon source, you are still hopeful you might salvage your project. You decide to grow a population of your engineered strain in a chemostat with napthalene as the only carbon source. What do you predict will most likely happen over many generations?

The population will evolve to more effectively utilize the napthalene.

Both tuna and dolphins have a streamlined body shape and large tail fins that they use to move through the water. Many other anatomical and molecular data indicate, however, that tuna and dolphins are not closely related from an evolutionary perspective. This suggests that _______.

Tuna and dolphins faced similar selective pressures on body shape for reproductive success

Parasitic species tend to have simple morphologies. Which of the following statements best explains this observation?

Simple morphologies have been naturally selected for in most parasites.

Many crustaceans (e.g. lobsters, shrimp, and crayfish) use their tails to swim, but crabs have reduced tails that curl under their shells and are not used in swimming. This is an example of _____.

a vestigial trait

The same basic internal organs (kidneys, stomach, heart, lungs) are found in frogs, birds, snakes, and rodents. This is primarily an example of _____.

structural homology

The Dunkers are a religious group that moved from Germany to Pennsylvania in the mid-1700s. They don't marry with members outside their own immediate community. Today, the Dunkers are genetically unique and differ in gene frequencies, at many loci, from all other populations including those in their original homeland. Which of the following likely explains the genetic uniqueness of this population?

founder effect and genetic drift

Wikelski and Romero (2003) found that large marine iguanas had higher reproductive success than smaller iguanas did. However, the large iguanas were generally in poor body condition because they could not eat enough; at higher temperatures their foraging efficiency improved, allowin them to eat more. Thus Wikelski and Romero hypothesize that iguana size will ____ as global warming gradually increases air and water temperature in the Galapagos Islands.

Increase

Currently the only predators of Galapagos marine iguanas are Galapagos hawks. Iguana body size is not correlated with risk of hawk predation, although small iguanas can sprint faster than large iguanas. If predators (ex. cats) that preferably catch and eat slower iguanas are introduced to the island, iguana body size is likely to ____ in the absence of other factors; the iguanas would then be under ____ selection.

decrease; directional

In 1986 a nuclear power accident in Chernobyl, USSR (now Ukraine), led to high radiation levels for miles surrounding the plant. The high levels of radiation caused elevated mutation rates in the surviving organisms, and evolutionary biologists have been studying rodent populations in the Chernobyl area ever since. Based on your understanding of evolutionary mechanisms, which of the following most likely occurred in the rodent populations following the accident.

Mutation led to increased genetic variation

An earthquake decimates a ground-squirrel population. The surviving population happens to have broader stripes on average than the initial population. If broadness of stripes is genetically determined, what effect has the ground-squirrel population experienced during the earthquake?

A genetic bottleneck

Many songbirds breed in North America in the spring and summer and then migrate to Central and South America in the fall. They spend the winter in these warmer areas, where they feed and prepare for the spring migration north and another breeding season. Two hypothetical species of sparrow, A and B, overwinter together in mixed flocks in Costa Rica. In spring, species A goes in the east coast of North America, and species B goes to the west coast. What can you say about the isolating mechanisms of these two species?

Their winter habitat has no bearing on their degree of reproductive isolation.

Agrobacterium is a type of bacteria that infects plants and causes them to form tumors. Tumor formation requires a large amount of the plant's energy for tissue formation. How might this change the number of offspring a plant produces, and what is the most likely explanation for this change?

The number of offspring should decrease because the plant will be spending lots of energy producing the tumors.

Which of the following does not tend to promote speciation?

Gene flow

Wich of the following is the most predictable outcome of increased gene flow between two populations?

decreased genetic difference between the two populations

An island in the middle of a large river houses a large population of ants. Damming of the river causes the island to flood and only the highest points of the island are now above water. The ants cannot swim, so are now in multiple isolated populations. Which of the following best describes this event?

isolation by vicariance

Which of the following would be useful in creating a phylogenetic tree of a taxon?

All of the above: morphological data from fossil species, behavioral data from living species, genetic sequences from living species

A rare species of newt is being studied by a young evolutionary biologist. She observes that female newts lay unusually large yolky eggs, but they abandon their nests as soon as the eggs are laid. Males, on the other hand, defend the territory around the nest and regularly bring the baby newts insects to feed on. The males also sleep with the babies to keep them warmer during cool nights. Which is mostly likely true about the newts?

The males are choosy about which females to mate with

A small number of birds arrive on an island from a neighboring larger island. This small population begins to adapt to the new food plants available on the island, and their beaks begin to change. About twice a year, one or two more birds from the neighboring island arrive. What effect do these new arrivals have?

Their arrival tends to slow adaptation to the new food plants

Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related tree frogs in South America. If reinforcement of postzygotic isolation is occurring, what would you expect if you compare the calls of the two species in zones of sympatry versus zones of allopatry?

Calls would be more different in areas of sympatry

Two groups of lizards that have long been living in allopatry have recently been reintroduced in the wild. When members of opposite groups mate, the hybrids are inviable. Which of the following could be expected to occur over the long term if the populations remain in sympatry?

Behavioral forms of isolation will develop

Your professor wants you to construct a phylogenetic tree of orchids. She gives you tissue from seven orchid species and one lily. What is the most likely reason she gave you the lily?

to serve as an outgroup

Which of the following statements best describes the rationale for applying the principle of parsimony in constructing phylogenetic trees?

similarity due to common ancestry should be more common than similarity due to convergent evolution

Which of the following is an example of homoplasy?

cell walls in plants and fungi

Which of the following organisms would be most likely to fossilize?
a) rare worm
b) common worm
c) common squirrel
d) rare squirrel

common squirrel - needs skeleton to fossilize

What event can trigger an adaptive radiation

a vicariance event splitting the habitat

Islands are well known for having many endemic species- species that are unique to that location. What is a likely explanation for this pattern?

Colonizers encounter fewer competitors on an island, so they can diversify

How do mass extinctions differ from background extinctions?

During mass extinctions a large proportion of organisms that were alive at that time die out.

Compared to unicellularity, multicellularity allows organisms to

grow larger and move faster

Which is the correct series of events in the history of life on Earth?

anaerobic metabolism --> photosynthesis --> O2 --> aerobic metabolism

Paleontologists believe that mammals evolved directly from

reptiles

Modern ___ represents the taxonomic group that originally bridged the gap between water-dwelling and land-dwelling vertebrates in the distant past

amphibians

Which group of vertebrates were the first to evolve a waterproof egg, allowing them to move further onto dry land?

reptiles

The predominant mechanism driving cellular differentiation is the difference in gene

expression

Communication within and between cells of an embryo can include all of the following except ____.

changes in gene sequences

Which observation below provides evidence that differentiated cells retain all the genes of developing cells?

Nuclei from mature cells can direct the development of an entire individual

Cloning of plants from cuttings demonstrates that ____.

mature plant cells retain genetic information

Gene expression in developing organisms is regulated on several different levels. In many developing animals, regulation of gene expression is influenced by the action of Hox genes. Which of the following regulatory elements is produced by many Hox genes?

transcriptional factors

Why would gene duplication events such as those seen the Hox gene complex, set the stage for adaptive radiation?

One copy of a gene can perform the original function while other copies are available to take on new functions.

Which of the following likely has the most Hox genes?
a) jellyfish
b) bees
c) dolphins
d) slugs

dolphins

The protein of the bicoid gene in Drosophila determines the ____ of the embroy.

Anterior; posterior axis

In combination, what do the products of gap genes, pair rule genes, and segmentation polarity genes of fruit flies do?

They define the segmented body plan of the embryo

What is common to gap genes, segment -polarity genes, and homeotic genes?

They code for transcription regulatory factors.

What happens during gastrulation?

The three embryonic tissue germ layers form

Which of the following is the most basic process in the developing embryo because all of the other processes listed can occure only after it or in conjunction with it?

Mitosis

Evolutionary theory has until recently stressed genetic mutations that alter protein amino acid sequences as the major source of variation that leads to speciation. Evo-devo (evolutionary developmental biology) offers a different understanding of the role of genetic change in evolution. Which of the following statements best summarizes this understanding?

Similar genes are found in most developing animals bodies; changes in the times and places they are expressed can lead to phenotypic variation

Sperm-egg interactions are species-specific in sea urchins, but not in mammals. What might be one reason for this difference?

Sea urchin fertilization occurs in open ocean

Suppose an antibody to bindin was introduced into a chamber containing sea urchin sperm and eggs. You predict that the antibody-treated sperm will _____.

not be attracted to bind to the egg membrane.

In snake populations, rare individuals are found that have well-developed hind limbs, but are normal in all other respects. These unusual snakes suggest that _____.

Mutations in genes that repress expression of hind limb organizer genes can cause snakes to have limbs; snakes retain the genes for hind limb pattern formation, even though the genes are usually not activated during development; some snakes have mutations in Hox genes that permit development of limbs

Which of the following would you not classify as an animal?
a) sponges
b) jellyfish
c) coral
d) choanoflagellates

d) choanoflagellates

An organism that exhibits cephalization probably also ____.

is bilaterally symmetrical

Which of the following is most likely to be aquatic?

suspension feeder

Which of teh following is a feature of the tube within a tube body plan in most animals?

The mouth and anus form the ends of the inner tube

Suppose a researcher for a pest-control company developed a chemical that inhibited the development of an embroyonic mosquito's endodermal cells. Which of the following would be a likely mechanism by which this pesticide works?

the mosquito would have trouble digesting food, due to impaired gut function

In examining an unkown animal species during its embryonic development, how can you be sure what you are looking at is a protostome and not a deuterostome?

you see a mouth, but not an anus

A radula is a pecialized feeding organ used to scrape material off of food for ingestion, much like a cheese grater scrapes shreds off of a block of cheese. Snails, which have this structure, are thus which kind of feeder?

mass feeder

What do biologists cite as the primary benefit of the evolution of a coelom in animals?

the hydrostatic skeleton, allowing greater range of motion

Why might researchers choose to use molecular data ( such as ribosomal RNA sequences) rather than morphological data to study the evolutionary history of animals?

Sequence data can be gathered faster than mophological data, and morphological data can lead to wrong conclusions.

One difference between a morula and a blastula is that ___.

a blastula has a hollow center, a morula doesn't

Yolk is mostly lipid and its primary function during development is to

provide energy for the egg

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