Learning Checks BIO 311D

Single-celled Paramecium live in pond water (a hypotonic environment relative to the cytosol). They have a structural feature, a contractile vacuole, which enables them to osmoregulate. If sucrose or saline was added to the pond water in different concentrations (in millimolars, mM), under which conditions would you expect the contractile vacuole to be most active?

0.0 mM sucrose

Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems?

Energy transfer between trophic levels is usually less than 20 percent efficient.

Select ALL correct statements regarding the Hardy Weinberg equilibrium: (assume we are discussion a 1 gene - 2 allele situation)

For a population in Hardy Weinberg equilibrium, if one allele frequency is given, you can calculate all genotype and phenotype frequencies.

What is the biological significance of genetic diversity between populations?

Genetic diversity reduces the probability of extinction.

An individual plant was discovered that could not grow towards light. After some research, it was determined that the reason was a defective gene that did not allow for the level of cell elongation necessary for a phototropic response. This mutation greatly reduces the fitness of the individual plant. Which reason best describes the reason for the loss of fitness?

The plant could not adjust to directional light, which reduced photosynthetic activity and therefore energy available for reproduction.

As N approaches K for a certain population, which of the following outcomes is predicted by the logistic equation?

The population growth rate will approach zero.

White seed color in beans is dominant to gray. Assume a series of experiments where plants with white seeds were crossed among themselves, and the following progeny were produced: 305 white and 98 gray. What is the most probable genotype of each parent? Correct!

Ww x Ww

'Amniotes' is the clade of vertebrates that have an amnion that allows for reproduction on land. Can we say that kangaroos belong in the amniote clade?

Yes, kangaroos are amniotes.

Which of the following animals most likely uses the largest percentage of its energy budget for homeostatic regulation?

a bird living year-round in a desert

During mammalian labor and delivery, the contraction of uterine muscles is enhanced by oxytocin. This is an example of ________.

a hormone that is involved in a positive feedback loop

Someone who studies the effect of temperature on the enzymatic processes of photosynthesis in a species of C4 grass is ______

a physiological ecologist

A human cell containing 22 autosomes and a Y chromosome is?

a sperm

Fight-or-flight reactions include activation of the ________.

adrenal medulla, leading to increased secretion of epinephrine

Use the following figure to answer the question.Which category in the figure makes available the highest productivity per square meter?

algal beds and reefs

House finches were found only in western North America until 1939, when a few individuals were released in New York City. These individuals established a breeding population and gradually expanded their range. The western population also expanded its range somewhat eastward, and the two populations have recently come in contact. If the two forms were unable to interbreed when their expanding ranges met, it would be an example of ________.

allopatric speciation

The duplication of homeotic (Hox) genes has been significant in the evolution of animals because it ________.

allowed for the evolution of more complex forms

Which of the following characteristics of plants is absent in their closest relatives, the charophyte algae?

alternation of multicellular generations

Plants often use changes in day length (photoperiod) to trigger events such as dormancy and flowering. It is logical that plants have evolved this mechanism because photoperiod changes ________.

are more predictable than air temperature changes

Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools?

biological

Introduced species can have deleterious effects on biological communities by ________.

competing with native species for resources and displacing them

The needles of some pine species contain chemicals that inhibit growth of understory plants. This is an adaptation in response to a species interaction. Which type of species interaction?

competition

Which of the following causes populations to shift most quickly from an exponential to a logistic population growth?

competition for resources

Nitrogen fixation is a process that ________

converts nitrogen gas into ammonia

Some organisms are labeled as being photo-heterotroph. The 'photo' part in this term tells us that they ________. Correct!

get their energy from sunlight

Analysis of a blood sample from a fasting individual who had not eaten for 24 hours would be expected to reveal high levels of ________.

glucagon

Snake behavior in Wisconsin changes throughout the year. For example, a snake is ________.

more active in summer because it can gain body heat by conduction

Ammonites are a group of marine mollusk animals that disappeared from the fossil record 65 million years ago. They are closely related to living octopuses, squid, and cuttlefish. Which 'species definition' can be used for this prolific group of organisms?

morphological species concept

Positive tropism is movement or growth towards a stimulus, whereas negative tropism is the movement or growth away from a stimulus. Knowing this we can state that plant shoots exhibit ______.

negative gravitropism and positive phototropism

Use the following figure to answer the question.Consider the global nitrogen cycle depicted in the figure. What is the limiting portion of the cycle for plants?

nitrogen fixation by bacteria

Atrial systole ______________.

occurs at the same time as ventricular diastole

You own 300 acres of patchy temperate forest mixed with grassy meadows. Which one of the following actions would increase the net primary productivity of the area the most?

planting 500 new trees

Just like animals, plants have the adaptation of increased surface areas to allow for the exchange of materials with the environment. E.g. root hairs are an adaptation to optimize the uptake/intake of:

water and inorganic nutrients

A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 49% of the animals display a recessive trait (aa), the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants.What is the estimated frequency of allele A in the gene pool?

0.7

Approximately how many kilograms (kg) of tertiary consumer biomass can be supported by a field plot containing 1000 kg of plant material?

1

Use the figure and the following description to answer the question.In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding, dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in the figure, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square. Which of the boxes marked 1-4 correspond to plants that will be true-breeding?

1 and 4 only

Albinism is a recessive trait. A man and woman both show normal pigmentation, but both have one parent who has albinism (without melanin pigmentation). What is the probability that their first child will have albinism?

1/4

Skin color in a certain species of fish is inherited via a single gene with four different alleles. One fish of this type has alleles 1 and 2 (S1S2), and its mate has alleles 2 and 4 (S2S4). If each allele confers a certain number of color darkness such that S1 has one unit, S2 has two units, and so on, where the units are additive, then what proportion of their offspring would be expected to have five units of color?

1/4

A porcupine eats 3,000 J of plant material. Of this, 2,100 J is indigestible and is eliminated as feces, 800 J are used in cellular respiration, and 100 J are used for growth and reproduction. What is the approximate production efficiency of this animal?

11%

Plant species A has a diploid number of 16. Plant species B has a diploid number of 12. A new species C arises as an allopolyploid from A and B. The diploid number for species C would probably be _____.

28

Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers, and the other has white, terminal flowers; all F1 individuals have red, axial flowers. The genes for flower color and location assort independently. Among the F2 offspring, what is the probability of producing plants with red, terminal flowers?

3/16

A population of ground squirrels has an annual per capita birth rate of 0.07 and an annual per capita death rate of 0.03. Using these birth and death rates, calculate an estimate of the total number of individuals added to (or lost from) a population of 1,000 individuals in one year.

40

In onions (Allium), cells of the sporophyte have 16 chromosomes within each nucleus. How many chromosomes should be in the nucleus of an egg within the embryo sac prior to fertilization?

8

Throughout the years, ecologists want to estimate the population size of sea otters. Assume that all conditions for a mark-recapture estimate are present. A team of marine ecologists captures and tags 20 sea otters and sets them free. A few weeks later, they re-capture 40 sea otters, of which only 1 is tagged. What is the estimate of the population size at this time?

800

Examine the digestive system structures in the figure. The agents that help emulsify fats are produced in location ________.

9

Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether or not cacti have spines. Homozygous recessive nn cacti have no spines at all. If cacti heterozygous for both traits, SsNn, were allowed to self-pollinate, the offspring would segregate into which of the following phenotype ratios?

9 sharp-spined:3 dull-spined:4 spineless

In the figure below, which two values indicate the driving force of carbon dioxide diffusing into our bloodstream?

>45 vs 40

Select ALL correct statements regarding mitosis and meiosis: A. The amounts of DNA in cells of a single species are the same at the end of mitosis of a diploid cell, as they are at the start of meiosis II. B. Mitosis is possible in both haploid and diploid cells. Meiosis is only possible in haploid cells. C. Barring any replication errors, sister chromatids in a single chromosome are always identical to each other. D. Sister chromatids are separated both in mitosis and meiosis II. However, there are only half as many sister chromatids during meiosis II, compared to mitosis of a diploid cell in the same species.

A and D

Organisms maintain dynamic homeostasis through behavioral and physiological mechanisms. Which of the following statements is a complete and accurate explanation of a negative feedback mechanism used by animals to regulate body temperature?

A ground squirrel's hypothalamus detects changes in environmental temperatures and responds by activating or suppressing metabolic heat production.

Eating a taco consisting of a flour tortilla with organic pork shoulder, salsa verde, queso fresco, cilantro, onion, and avocado engages the following A. amylases in small intestine B. amylases in saliva C. bile salts in the small intestine D. pepsin in our stomach

A, B, C, D

Neil Shubin was instrumental in finding the connection between fish and land living vertebrates. Select ALL correct statements. [Note: the Devonian is a period in the Paleozoic. Tiktaalik is a fossil from the Devonian] A. The transition occurred gradually over time, so there are many intermediate forms. B. There are no tetrapod fossils in the geologic record before the Devonian. C. Tiktaalik had characteristics of both fish (scales, fins, and fin rays) and tetrapods (flat head, eyes on top, strong interlocking ribs, and a neck). D. Tiktaalik's characteristics would have enabled it to survive both in and out of water, like amphibians and reptiles today.

A, B, C, D

Select ALL correct statements regarding Mendel's Law of Independent Assortment: A. Mendel's second law is equivalent to the random assortment of homologous chromosome pairs in metaphase I of meiosis. B. In the classic Mendel cross, the Law of Independent Assortment predicts more phenotypic combinations in the F2 generation than in the P generation. C. The self-crossing of a dihybrid can be represented by a 4X4 Punnett square. D. The Law of Independent Assortment is applicable to two genes located on separate chromosomes.

A, B, C, D

Use the following figures to answer the question below. ​ Based on the data in the figures, which of the following statements are correct? (select all that apply) A. Area 1 has more average precipitation than Area 2 B. Area 2 might be considered a desert because of it's relatively high temperature C. Area 2 might be considered a desert because of its low precipitation amounts. D. Area 2 has a higher annual temperature variation compared to Area 1.

A, C, D

A black guinea pig crossed with a guinea pig with albinism produced 12 black offspring. When the albino was crossed with a second black animal, six blacks and six albinos were obtained. What is the best explanation for this genetic situation?

Albinism is a recessive trait; black is a dominant trait.

Endosymbiosis is an evolutionary theory that explains the origin of eukaryotes and suggests a specific order in which this might have occurred. Ancestral cells engulfed and then began to use the metabolic processes of the smaller cells. Based on shared processes and features, which statement most accurately describes the order, the theory, and the evolutionary implications for all organisms within domain Eukarya?

As Earth was becoming more aerobic, mitochondria would have provided an advantage to host cells by converting "toxic" oxygen into energy for heterotrophic cells. Since mitochondria are found in all eukaryotes, these combinations likely evolved first. Photosynthetic eukaryotes probably acquired an autotrophic prokaryote, which developed an advantageous symbiotic relationship with the host cell.

In human blood types, Rh positive is a trait that shows simple dominance over Rh negative. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Which of the following phenotypes is possible for the father?

B positive

The discussion activity this week focused on Information Literacy Skills. Which of the following skills were introduced and practiced? Select all that apply. A. Analysis of a peer-reviewed paper using guiding questions for abstract, introduction, methods and results. B. Finding articles in the Web of Science database. C. Construction of keyword strings to perform searches. D. Using the CRAAMP framework to assess validity of a source.

B, C, D

Why does the fitness of a phenotype depend on frequency-dependent selection?

Because selection favors the least common phenotype.

The haploid gametophytes of bryophytes are ________.

usually multicellular, but one cell thick

Use the following figure to answer the question.Diagram of a food web (arrows represent energy flow and letters represent species)If the figure represents a marine food web, zooplankton are most likely ________.

C

The figure below shows us the spread and phylogeny of the SAR-CoV-2 virus, also known as the corona virus, that is causing the current worldwide pandemic. What can we learn from this figure? A. That the corona virus is mutating. B. That the virus originated in China in late 2019 C. All answer choices are correct. D. That different regions have different versions of Corona virus.

C. All answer choices are correct

The convoluted shape of mesophyll cells leads to a high surface-to-volume ratio in leaves. This is an adaptation to aid ___.

CO2 absorption

Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They wondered if the same fungal individual would colonize different trees, forming an underground network that potentially could transport carbon and nutrients from one tree to another Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years (Fig. A). Two of the three species (Douglas fir, birch) could form ectomycorrhizal connections with the same fungal species, but the third species (cedar) could not form an ectomycorrhizal connection with the fungal species. In some of the pots, the researchers placed airtight bags over the Douglas fir and birch seedlings and injected carbon dioxide made from carbon-13 into the bags with the Douglas fir and carbon dioxide made from carbon-14 into the bags with the birch. (13C and 14C are different isotopes of carbon that can be detected and measured by researchers.) As the seedlings photosynthesized, the carbon dioxide was converted into sugars that could be tracked and measured by the researchers. The researchers measured whether the sugars in each plant contained only the carbon isotope that was in the air of their plastic bag or also the carbon isotope from the air around the other plant. Which of the following results support the hypothesis that fungi can move carbon from one plant to another? [Hypothesis: Sugars made by one plant during photosynthesis can travel through a mycorrhizal fungus and be incorporated into the tissues of another plant.] (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the field. Nature 388:579-82).

Carbon-14 is found in the Douglas fir seedling's tissues and carbon-13 in the birch.

If two animals share the characteristic of having an internal skull with a jaw, what other characteristic(s) will they share? A. having deuterostome development B. having four limbs C. all answer choices are correct D. multiple answers, but not all, are correct E. having a spine (vertebrae)

D

Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true?

Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted.

DNA was isolated from three different cell types of the same organism, the relative DNA content for each type was determined, and the results were plotted on the graph shown in the figure below. Refer to the graph to answer the following questions. Which sample of DNA might represent a zygote?

I

Refer to the drawings in the figure below of a single pair of homologous chromosomes as they might appear during various stages of either mitosis or meiosis, and answer the following question(s).Which diagram represents anaphase I of meiosis?

I

The following question refers to the following phylogenetic trees. ​ Which tree depicts the closest relationship between zygomycetes and chytrids?

I

Transpiration in plants requires ________. I)adhesion of water molecules to cellulose II)cohesion between water molecules III)evaporation of water molecules IV)active transport through xylem cells V)transport through tracheids

I, II, III, and V

Refer to the life cycles illustrated in the figure below to answer the following questions. The 3 diagrams are labeled I, II, III from left to right. Which of the life cycles is typical for plants, and what do you base your answer on?

II - it shows mitosis in the haploid and the diploid stage

Which of the following is a generally accurate statement about the current research regarding forest fragmentation?

In fragmented forests, the number of forested-adapted species tend to decline and the number of edge species tend to increase.

Which of the following statements describes a major difference between meiosis II and mitosis in a diploid animal?

Meiosis II occurs in a haploid cell, while mitosis occurs in diploid cells.

A patient is hospitalized with muscle spasms caused by failure of back muscles to relax after contraction. Which of the following would be most likely to help?

Induce tropomyosin and troponin to bind to the myosin binding sites on actin.

Use the following information to answer the question.Giardia intestinalis can cause disease in several different mammalian species, including humans. Giardia organisms (G. intestinalis) that infect humans are similar morphologically to those that infect other mammals, thus they have been considered a single species. However, G. intestinalis has been divided into different subgroups based on their host and a few other characteristics.In 1999, a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species. The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G. intestinalis and a few other morphologically distinct species of Giardia. The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species. (T. Monis, et al. 1999. Molecular systematics of the parasitic protozoan Giardia intestinalis. Mol. Biol. Evol. 16[9]:1135-44.) By examining the phylogenetic tree diagrammed in the figure above, what conclusion can you draw about the species G. microti?

It is part of a monophyletic group that also includes G. intestinalis.

Ecology and evolution are closely related fields as shown in this diagram Which of the following statements is an example of a way how ecology influences evolution? (arrow on the right side of the diagram)

Light moths being eaten by birds because they stand out against the (new) dark background.

Elevated carbon dioxide levels have been shown to contribute to the greenhouse effect, resulting in an increase in mean global temperature. Ecosystems where the largest warming has already occurred include snow-covered northern coniferous forests, tundra, and arctic sea ice habitats. Which statement best explains how the elimination of ice-covered ecosystems affects the rise or fall in global temperature?

More reflective surfaces of ice are replaced with darker, more absorptive surfaces, thereby contributing to the warming trend.

Which of the following is a correct statement about sugar movement in phloem?

Movement can occur both upward and downward in the plant.

Which statement is INCORRECT about the oxygen revolution?

Plants were responsible for the increase in atmospheric oxygen.

Among plants known as legumes (beans, peas, alfalfa, clover, for example) the seeds are contained in a fruit that is itself called a legume, better known as a pod. Upon opening such pods, it is commonly observed that some ovules have become mature seeds, whereas other ovules have not. Thus, which of the following statements is/are likely accurate?

Pollen tubes did not enter all of the ovules in such pods, and fruit can develop even if all ovules within have not been fertilized.

The common edible frog of Europe is a hybrid between two species, Rana lessonae and Rana ridibunda. The hybrids were first described in 1758 and have a wide distribution, from France across central Europe to Russia. Both male and female hybrids exist, but when they mate among themselves, they are rarely successful in producing offspring. What can you infer from this information?

Postzygotic isolation exists between the two frog species.

Based on this tree, which statement is correct?

Salamanders are a sister group to the group containing lizards, goats, and humans.

If you place a small piece of a cracker on your tongue, what would you expect to happen?

Salivary amylase degrades the starch from the cracker into glucose.

Genetic variation leads to genetic diversity in populations and is the raw material for evolution. Biological systems have multiple processes, such as reproduction, that affect genetic variation. They are evolutionarily conserved and shared by various organisms. Which of the following statements best represents the connection between reproduction and evolution?

Sexual reproduction increases genetic variation because random mutations can be shuffled between organisms.

Select the correct statement regarding sexual and asexual reproduction, in the context of evolutionary processes:

Sexual reproduction results in many new gene combinations, some of which can lead to differential reproductive success.

Assuming equal spore production rates, what is the likely consequence in a bryophyte with both asexual and sexual reproduction versus one with only sexual reproduction?

Species with both types of reproduction have higher population growth rates than species with only sexual reproduction.

Which of the following statements about stomata is accurate?

Stomata are important in terrestrial plants because they allow CO2 to diffuse into the plant.

What is the most important benefit gained by intestinal bacteria living in a mutualistic relationship with an animal?

The bacteria are provided with a regular source of nutrients.

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?

The two forms interbreed often in nature, and their offspring survive and reproduce well.

Which of the following statements about human evolution is correct?

The upright posture and enlarged brain of humans evolved separately.

What would be the effect on climate in the temperate latitudes if Earth were to slow its rate of rotation from a 24-hour period of rotation to a 48-hour period of rotation?

There often would be a larger range between daytime high and nighttime low temperatures.

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?

These two species mate in different climates.

Two animals have in common that they are triploblastic. Which of the following is an INCORRECT inference from this?

They both are invertebrates.

Which of the following is NOT a characteristic of all animals?

They have tissues, organs, and organ systems.

Which of the following is a consequence of biological magnification?

Toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers.

You are maintaining a small population of fruit flies in the laboratory by transferring the flies to a new culture bottle after each generation. After several generations, you notice that the viability of the flies has decreased greatly. Recognizing that small population size is likely to be linked to decreased viability, the best way to reverse this trend is to ________.

cross your flies with flies from another lab

The bulldog ant has a diploid number of two chromosomes. Therefore, following meiosis, each daughter cell will have a single chromosome. In addition to mutations, how might genetic diversity be generated in this species?

crossing over and random fertilization

The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence?

cyanobacteria → green algae → land plants

Imagine you are resting comfortably on a sofa after dinner. This could be described as a state with ________.

decreased activity in the sympathetic nervous system, and increased activity in the parasympathetic and enteric nervous systems

Male three-spined stickleback (Gasterosteus aculeatus) are small fish that can be found in northern coastal inland waters. While studying these creatures, you notice that males with a vivid red coloration on their undersides, get more opportunities to mate and father more offspring. To test the hypothesis that having a bright red belly is adaptive in these males, you first should _____

determine if the belly color is heritable

Three-spined stickleback fish (Gasterosteus aculeatus) show substantial heritable variation in gill-raker length related to differences in their diets. Longer gill rakers appear to function better for capturing open-water prey, while shorter gill rakers function better for capturing shallow-water prey. Which of the following types of selection is most likely to be found in a large lake (open water in the middle and shallow water around the sides) with a high density of these fish?

disruptive selection

A water molecule could move all the way through a plant from soil to root to leaf to air and pass through a living cell only once. This cell would be part of which structure?

endodermis

Which of the following outcomes is caused by excessive nutrient runoff into aquatic ecosystems?

eutrophication

In the demographic transition of the human population - what was a major determinant in the decrease of the birth rate?

female access to education and workforce

Use the following information to answer the question.Big Bend National Park in Texas is mostly Chihuahuan desert, where rainfall averages about 25 centimeters per year. Yet, it is not uncommon when hiking in this extremely arid zone to encounter mosses and ferns. One such plant is called "flower of stone." It is not a flowering plant, nor does it produce seeds. Under arid conditions, its leaflike structures curl up. However, when it rains, it unfurls its leaves, which form a bright green rosette on the desert floor. Consequently, it is sometimes called the "resurrection plant." At first glance, it could be a fern, or a moss.Which of the following characteristics is (are) possessed in common by true mosses, ferns, and spike mosses, and therefore becomes useless at helping to determine to which of these groups "flower of stone" belongs?

flagellated sperm and alternation of generations

Elephants hear sounds that are too low for humans to hear. This sensitivity is primarily due to the differences in the ________.

flexibility of the basilar membrane in the cochlea

In the oceans on either side of the Isthmus of Panama are 30 species of snapping shrimp; some are shallow-water species, others are adapted to deep water. There are 15 species on the Pacific side and 15 different species on the Atlantic side. The Isthmus of Panama started rising about 10 million years ago from the bottom of the ocean floor. The oceans were completely separated by the isthmus about 3 million years ago. In the figure, the isthmus separates the Pacific Ocean on the left (side A) from the Atlantic Ocean on the right (side B). The seawater on either side of the isthmus is separated into five depth habitats (1-5), with 1 being the shallowest and 5 the deepest. Which of these habitats is likely to harbor the most recently diverged species?

habitat 1

C4 plants have a low stomatal conductance, which helps reduce their water loss. They can do this because they _____.

have a CO2 concentrating mechanims

Plasmogamy can directly result in which of the following?

heterokaryotic cells or dikaryotic cells

In the formula for determining a population's genotype frequencies, the "2" in the term 2pq is necessary because ________.

heterozygotes can come about in two ways

Which of the following observations provides the best evidence of a biodiversity crisis?

high rate of extinction

After a midday rain shower, the water potential of the atmosphere will be __________ compared to warmer, dryer air. The water potential inside guard cells will ________________ as a response.

higher; decrease

In the 2011 dramatic movie 'Contagion', a virus causes a worldwide pandemic and social distancing is implemented around the globe. In the movie, epidemiologists study the genetic code, molecular structure, and origin of the virus that causes the disease. At one point, they mention that both bat and pig DNA code is found within the viral genetic code - meaning that both mammal species were host to the virus, before the virus started using humans as a host. This is most obvious a case of:

horizontal gene transfer

Rods exposed to light will ________.

hyperpolarize due to the closing of sodium channels

Hormones secreted by the posterior pituitary gland are made in the ________.

hypothalamus

Glucocorticoids do which of the following?

increase blood glucose levels

Which of the following experimental procedures would most likely reduce transpiration while allowing the normal growth of a plant?

increasing the level of carbon dioxide around the plant

Absorptive nutrition _________

is when fungi secrete digestive enzymes that break down organic matter externally

Overharvesting encourages extinction and is most likely to affect ________.

large animals with low intrinsic reproductive rates

In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common?

length, centromere position, staining pattern, and traits coded for by their genes

Upon exposure to blue light, plants not only begin to grow toward the light, but move their chloroplasts to the sunny side of each cell. The adaptive advantage of moving chloroplasts to the sunny side of each cell ________.

maximizes light absorption by the chloroplasts for photosynthesis

The following question refers to the generalized life cycle for land plants shown in the figure. Each number within a circle or square represents a specific plant or plant part, and each number over an arrow represents meiosis, mitosis, or fertilization.In the figure, the process labeled "6" involves ________.

mitosis

Use the information to answer the following question.The Brazil nut tree, Bertholletia excels (n = 17), is native to tropical rain forests of South America. It is a hardwood tree that can grow to over 50 meters tall, a source of high-quality lumber, and a favorite nesting site for harpy eagles. As the rainy season ends, tough-walled fruits, each containing 8-25 seeds (Brazil nuts), fall to the forest floor. Brazil nuts are composed primarily of endosperm. About $50 million worth of nuts are harvested each year. Scientists have discovered that the pale yellow flowers of Brazil nut trees cannot fertilize themselves and admit only female orchid bees as pollinators. The agouti (Dasyprocta spp.), a cat-sized rodent, is the only animal with teeth strong enough to crack the hard wall of Brazil nut fruits. It typically eats some of the seeds, buries others, and leaves still others inside the fruit, which moisture can then enter and allow the remaining seeds to germinate.Entrepreneurs attempted, but failed, to harvest nuts from plantations grown in Southeast Asia. Attempts to grow Brazil nut trees in South American plantations also failed. In both cases, the trees grew vigorously, produced healthy flowers in profusion, but set no fruit. Consequently, what is the likely source of the problem?

pollination failure

In a community with strong top-down control, what is the effect of a carnivore (secondary consumer) on plant species (primary producer)?

positive effect

Consider a human population that is in a pandemic: a disease causing virus is spreading in this population. One person can infect several other persons. These newly infected persons in turn are infecting other persons and so on. The more people that are infected, the more new people will get affected in a next time step. Is this an example of a positive or a negative feedback?

positive feedback

Use the following figure to answer the question.In the ecosystem figure, which unit of the food web has the potential to lose the most energy as heat?

primary producers

If all fungi in an environment that perform decomposition were to suddenly die, then which group of organisms should benefit most, due to the fact that their fungal competitors have been removed?

prokaryotes

A woman standing and watching the stars on a cool, calm night will lose most of her body heat by ________.

radiation

What would be the consequence if we were to reverse the direction of water flow over the gills of a fish, moving water inward past the operculum, past the gills, then out the mouth? This reversal of water flow would ________.

reduce efficiency of gas exchange

Which of these events, based on plant fossils, came last (most recently)?

rise and diversification of angiosperms

The operation of the sodium-potassium pump moves ________.

sodium ions out of the cell and potassium ions into the cell

Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers, but they mate while inside of the flowers. A mutant version of the plant, now with red flowers, becomes more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occurred in this example, and what has driven it?

sympatric speciation; habitat differentiation

Use the following figures to answer the question below.East of the Mississippi River, in Hopkinsville Kentucky, the mean annual precipitation is 130 cm. The mean annual temperature is 14.3°C. In the winter, the mean temperature is 7.3°C, while in summer it is 20.6°C. Using the climograph shown here, how would we classify the biome found in Hopkinsville?

temperate broadleaf forest

Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus, ________.

the allele's frequency should not change from one generation to the next

Burning fossil fuels releases oxides of sulfur and nitrogen. These air pollutants can be responsible for ________.

the death of fish in lakes

The greatest difference in the concentration of respiratory gases is found in which of the following pairs of mammalian blood vessels?

the pulmonary vein and the superior vena cava

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

In cats, black fur color is determined by an X-linked allele; the other allele at this locus determines orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?

tortoiseshell females; black males

The conversion of a stimulus into an action potential by a receptor cell is called ________.

transduction

The main goal of sustainable development is to ________.

use natural resources such that they do not decline over time

If the DNA content of a diploid cell in the G1 phase of the cell cycle is x, then the DNA content of a single cell at metaphase of meiosis II will be?

x

Type 1 diabetes happens when your cells that make insulin (beta cells) in the pancreas are destroyed. What destroys them?

your immune system