BISC208 Mastering Biology Exam 1 (University of Delaware, Dr. DeVito)

Phenotypic plasticity is more important in...

long-lived species

Loss of water from the aerial parts of plants is called...

transpiration

The surface area of a plant's root system is substantially larger than the surface area of its shoot system. The extensive surface area of roots is an adaptation associated with...

contact with soil particles for mineral and water absorption

What is meant by phenotypic plasticity in roots and shoots?

The ability to modify form depending on environmental conditions

Carbon dioxide enters the inner spaces of the leaf through the...

stoma

A student examining leaf cross sections under a microscope finds many loosely packed cells with relatively thin cell walls. The cells have numerous chloroplasts. What type of cells are they?

parenchyma

The veins of leaves are...
I) composed of xylem and phloem
II) continuous with vascular bundles in the stem and roots
III) finely branched to be in close contact with photosynthesizing cells

I, II, III

Which structure is correctly paired with its tissue system?
I) tracheid - vascular tissue
II) guard cell - vascular tissue
III) companion cell - ground tissue
IV) root hair - vascular tissue

I) tracheid - vascular tissue

Which cells primarily transport sugars over long distances?

sieve-tube elements

Water transport is the primary function of which cell type?

Tracheids

Which cell types retains the ability to undergo cell division?

a parenchyma cell near the root tip

The water lost during transpiration is a side effect of the plant's exchange of gases. However, the plant derives some benefit from this water loss in the form of...

evaporative cooling and mineral transport

Most of the water taken up by a plant is...

lost during transpiration

The value for Ψ in root tissue was found to be -0.15 MPa. If you take the root tissue and place it in a 0.1 M solution of sucrose (Ψ = -0.23 MPa), the net water flow would be...

from the tissue into the sucrose solution

When an animal cell is placed in a hypotonic solution and water enters the cell via osmosis, the volume of the cell increases until it bursts. This does not happen to plant cells, because...

they have cell walls, which provide pressure to counteract the pressure of the incoming water

In which conditions would transpiration be expected to be highest?

A hot, dry, and windy day

Which of the following statements about bulk flow are correct?
I) Bulk flow is driven primarily by pressure potential.
II) Bulk flow depends on a difference in pressure potential at the source and sink.
III) Bulk flow depends on the force of gravity on a column of water
IV) Bulk flow may be the result of either positive or negative pressure potential.

I, II, and IV

What drives the flow of water through the xylem?

the evaporation of water from the leaves

Root hairs are most important to a plant because they...

increase the surface area for absorption

Water potential is generally most negative in which parts of a plant?

mesophyll cells of the leaf

Which theory of water transport in xylem can also be used to explain the primary movement of water in nonvascular plants such as mosses?

capillary

Photosynthesis ceases when leaves wilt, mainly because...

stomata close, preventing carbon dioxide from entering the leaf

What would tend to increase transpiration?

higher stomatal density

Which of the following structural features of plants would NOT be expected to reduce transpiration?
I) reduced leaf size
II) stomata on upper and lower surfaces of leaf
III) abundant epidermal hairs on leaves and stems
IV) thick cuticle on leaves and stems
V) sunken stomata

II) stomata on upper and lower surfaces of leaf

Some plants growing in arid climates have small leaves and thick waxy cuticles on the upper epidermis. This is an adaptation for...

decreasing water loss from leaves

According to the pressure-flow hypothesis, which direction are sucrose and water flowing in the phloem when roots are sources and leaves are sinks?

Water and sucrose flow up the stem

The water potential of phloem sap is lowest in which season / time?

Near leaves at the start of spring

Movement of phloem sap from a source to a sink depends upon...

active transport of sugars into the sieve-tube elements

Which primary meristem gives rise to the vascular tissue system?

Procambium

Plants contain meristems whose major function is to

produce more cells

Which part of the root or leaf has the lowest (most negative) water potential?

leaf air spaces

The flow of xylem from root to leaf in a tall tree is principally due to

a decrease in water potential in the leaves due to evaporation

What is the force behind the process known as "transpiration" in plants?

Cohesion-tension

Why do only some of the plant cells exposed to a particular hormone respond?

Only some cells have the receptors for the hormone

Using purified auxin, how would you manipulate a bed of roses to have stems that bend to the east?

Place the auxin on the west side of their stems

Charles and Francis Darwin concluded from their experiments on phototropism by grass seedlings that the part of the seedling that detects the direction of light is the...

Tip of the coleoptile

What conclusion is supported by the research of both Went and Charles and Francis Darwin on shoot responses to light?

A chemical substance involved in shoot bending is produced in shoot tips

What are phototropins?

A group of blue-light receptors

Why is the hypersensitive response adaptive even if it results in the death of plant cells?

Cell death of virally infected cells and their neighbors prevents the dispersal of virus to other parts of the plant

The apical bud of a shoot produces ________, resulting in the inhibition of lateral bud growth.

Auxin

Plant hormones can have different effects at different concentrations. This explains...

Auxin can stimulate cell elongation in apical meristems yet inhibit the growth of axillary buds

The dropping of leaves and fruit are principally controlled by...

Ethylene

You have a small tree in your yard that is the height that you want it, but it does not have as many branches as you want. How can you prune it to trigger it to increase the number of branches?

Cut off the tips of the main shoots

What is the most likely plant response to an attack by herbivores?

Production of chemical compounds for defense or to attract predators of the herbivores

True or false? Plants do not produce many defenses against pathogens unless they are threatened because defensive structures and compounds require much energy and materials to produce and maintain.

True

What is the initial localized response of a resistant plant to pathogen invasion?

Hypersensitive response

How does a plant defend against herbivores?

The hormone systemin is produced at the site of injury and signals the plant to produce proteinase inhibitors

For a plant to initiate chemical responses to herbivory before it is directly attacked by herbivores...

volatile "signal" compounds must be perceived

When an arborist prunes a limb off a valuable tree, he or she may paint the cut surface with a nontoxic sealant. The primary purpose of the paint is to...

block entry of pathogens through the wound

Systemic acquired resistance (SAR) in a plant in response to a pathogen attack means...

the plant induces resistance in other parts of the plant by sending a message about the infection

A plant seedling bends toward sunlight because...

auxin is found in greatest abundance on the dark side of the stem

What is the physical basis of the phototropic response?

Cell elongation

True or false? Auxin is asymmetrically distributed in shoots because the auxin on the side of the plant facing the source of light is destroyed.

False

Where does the majority of stem growth in a plant occur?

Apical meristem

How does auxin produce gravitropism in a plant that is placed on its side?

Auxin accumulates on the lower surface of the root and inhibits elongation of cells in that region

How does auxin produce phototropism?

Auxin accumulates in cells on the side of the plant opposite the source of light and stimulates their elongation.

Why do plants have one hormone that promotes seed germination and another that suppresses seed germination? Why not just have one or the other?

Antagonistic hormones allow finer control of germination

According to the current evidence, what is the major function of cytokinins in plants?

Cell division by activating cell-cycle-promoting genes

If you were shipping green bananas to a supermarket thousands of miles away, which of the following chemicals would you want to eliminate from the plants' environment?

Ethylene

You are part of a desert plant research team trying to discover crops that will be productive in arid climates. You discover a plant that, under water-deficit conditions, produces a hormone that triggers a suite of drought responses. Most likely the hormone is...

Abscisic acid

Plant growth regulators...

often have a multiplicity of effects

After some time, the tip of a plant that has been forced into a horizontal position grows upward. This phenomenon is related to...

auxin movement toward the lower side of the stem

Why might a dwarf plant produce more seeds than a normal plant that received the same amount of sunlight and performed the same amount of photosynthesis?

Energy not spent on growth is shunted to reproduction

Many plants are capable of responding very rapidly to mechanical stimuli. For instance, Venus Flytraps respond more quickly than their insect prey can escape. A very mild touch or a light breeze can cause the leaves of the Sensitive Plant to close tightly. This rapid transmission of touch is accomplished by...

self-propagating changes in membrane potential

Which of the following can be sensed by plants?
I. gravity
II. pathogens
III. wind
IV. light

I, II, III, and IV

f cells in the _____ are removed, roots will no longer respond to gravity

Root cap

Seed germination is induced by red light and inhibited by far-red light. What is responsible for this phenomenon?

Phytochrome changing its shape when exposed to red versus far-red light

Which signal indicates shade to a plant?

Far-red light

The detector of light during de-etiolation (greening) of a tomato plant is...

phytochrome

What light exposure would increase the level of the Pfr form of phytochrome?

Red light

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it _____.

dismissed the idea that species are constant and emphasized the importance of variation and change in populations

What is plausible evidence supporting the hypothesis that birds evolved from dinosaurs?

Fossilized transitional forms are discovered that possess features of birds and dinosaurs yet are difficult to classify into either group.

Which of the following is the best modern definition of evolution?

descent with modification

Which of the pairs of plant structures below are homologous?

rose bush leaf and oak tree leaf

Which of the following most strongly supports the common origin of all life on Earth? All organisms ________.

use essentially the same genetic code

About thirteen different species of finches inhabit the Galápagos Islands today, all descendants of a common ancestor from the South American mainland that arrived a few million years ago. Genetically, there are four distinct lineages, but the thirteen species are currently classified among three genera. The first lineage to diverge from the ancestral lineage was the warbler finch (genus Certhidea). Next to diverge was the vegetarian finch (genus Camarhynchus), followed by five tree finch species (also in genus Camarhynchus) and six ground finch species (genus Geospiza). If the six ground finch species have evolved most recently, then which of these is the most logical prediction?

Their genomes should be more similar to each other than are the genomes of the five tree finch species.

What must be true of any organ described as vestigial?

It must be homologous to some feature in an ancestor.

In biology, fitness is defined as _____.

the ability of an individual to produce surviving offspring

Given a population that contains genetic variation, what is the correct sequence of the following events under the influence of natural selection?
1. Well-adapted individuals leave more offspring than do poorly-adapted individuals.
2. A change occurs in the environment.
3. Genetic frequencies within the population change.
4. Poorly-adapted individuals have decreased survivorship.

2 → 4 → 1 → 3

If you say that a ground squirrel has greater evolutionary fitness than another ground squirrel in the same population, you mean that the animal

has more offspring that survive and reproduce themselves.

Which concept(s) for identifying species cannot be applied to asexual or fossil species?

Biological species concept

Biological, morphological, and phylogenetic species concepts allow biologists to identify evolutionarily independent groups because they all rely on criteria indicative of _____.

no gene flow between populations

Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate between the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees.
What keeps the two populations separate?

habitat isolation

Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate between the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees.
The two populations are ________.

different subspecies, under the morphological species concept

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 to 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.

Which of the following forms a monophyletic group?

Pyrodicticum, Thermoproteus, and Halophiles

Which of the following statements about species, as defined by the biological species concept, is (are) correct?
I. Biological species are defined by reproductive isolation.
II. Biological species are the model used for grouping extinct forms of life.
III. All members of a species can potentially interbreed.

I and III

The largest unit within which gene flow can readily occur is _____.

a species

Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if true, would be cause for this reclassification?
a) The two forms live in similar habitats.
b) The two forms have similar food requirements.
c) The two forms have many genes in common.
d) The two forms are very similar in coloration.
e) The two forms interbreed often in nature, and their offspring have good survival and reproduction.

e) The two forms interbreed often in nature, and their offspring have good survival and reproduction.

What is genetic drift?

A change in allele frequencies caused by random events

True or false? The last ice age produced many different species mainly because populations dispersed and colonized new habitats.

False

Reinforcement is

a type of natural selection

A subset of a population of birds leaves its habitat on the mainland and colonizes a nearby island. The birds, after a period of time, become reproductively isolated. The island sinks and the population of birds that lived on the island returns to itsoriginal habitat. Will these populations be able to interbreed and why?

The populations will not be able to interbreed because they are different species.

A population of birds colonizes an area in which the insects upon which they feed live inside trees. Which of the following events accounts for an observed increase in average beak size in the bird population over time based on fitness change and what it caused.

Increased fitness of large-beaked birds, leading to natural selection

True or false? A flood that separates a population of frogs onto opposite sides of a lake is an example of a vicariance event that may result in allopatric speciation.

True

If you understand how ancestor−−descendant relationships are shown in trees, you should be able to draw a small tree that shows the relationship between humans and our closest living relatives, chimpanzees, and label and explain what the node means.

The node is the point where the chimpanzee and human branches meet. This is the inferred ancestor of chimpanzees and humans (which is neither chimpanzee nor human).

The approach to estimating phylogenetic trees is most like the approach of which species concept?

phylogenetic species concept

True or false? The absence of a trait cannot be used as a synapomorphy in phylogenetic analysis, only shared derived traits that are present in the clade can be used.

False; the loss of a trait, such as the loss of legs in snakes, can be a valuable synapomorphy for a clade.

Which of the following would be useful in creating a phylogenetic tree of a vertebrate taxon?
I. morphological data from fossil species
II. genetic sequences from living species
III. behavioral data from living species

I, II, and III

Parsimony assumes that the tree with _____ number of character changes is the most likely to represent evolutionary history.

the fewest