Exam 2 Bio1520
What happens during the follicular phase of the ovarian cycle? Select all that apply. Structures in the ovary produce estrogen Structures in the ovary produce progesterone FSH and LH are present Eggs are developing One or more eggs has been released and will implant in the uterus if fertilization has occurred
A, C, and D
Which of the following observations supports the "good genes" hypothesis to explain male/male competition and female choice? The color and quality of male sage grouse air sacs, used in courtship displays, are extremely sensitive to parasitic infections Ring-tailed lemurs mate only during the autumn breeding season, and females are not receptive to males at other times of the year Female widowbirds prefer males with the longest tails, but males with longer tails are more susceptible to predation Human males with symmetrical faces are considered more attractive than those with asymmetrical faces
A, C, and D any trait that is BOTH an 'honest indicator' of genetic health AND something that females find attractive would be consistent with the good genes hypothesis to explain male/male competition and female choice. air sacs are susceptible to infection, meaning that they honestly indicate the 'good genes' of the male to females. longer tails hinder survival in the presence of predators, so a male that has a long tail and has escaped predation has 'good genes'. symmetry is biologically challenging to achieve, and thus is also an indicator of 'good genes'
what phase does birth control pill mimic?
luteal phase
Secretions from which part of the male reproductive anatomy in humans produces molecules that stimulate smooth muscle contractions in the uterus of females? seminal vesicles testes bulbourethral gland prostate gland
A sperm are produced in the seminiferous tubules within the testes. the seminal vesicles produce fructose and prostaglandins added to semen immediately prior to ejaculation; fructose is a source of chemical energy for sperm movement, and prostaglandins stimulate smooth-muscle contractions in the uterus to aid sperm movement into the oviducts. the bulbourethral glands produce alkaline mucus added to semen immediately prior to ejaculation, which helps to lubricate the tip of the penis and neutralize acids in the urethra. the prostate gland produces antibiotics and citric acid (an additional source of nutrients for sperm) to semen immediately prior to ejaculation.
Which of the following best describes the ploidy level of the cells found in the embryo sac after fertilization? There are haploid, diploid, and triploid cells. All cells are polyploid. All cells are triploid. All cells are diploid. The ploidy level varies among species.
A the antipodal cell sand synergid cells are haploid; the embryo is diploid, and the endosperm is triploid.
Diplontic life cycles are characteristic of: animals plants fungi single-celled eukaryotes prokaryotes (bacteria and archaea)
A
The nervous system originates from ectoderm mesoderm endoderm
A the nervous system originates from ectodermal tissue which folds in on itself to create the neural tube (which will become the brain and the nerves of the vertebral column in vertebrates). the creation of the neural tube is due to signals from the underlying notochord.
During cleavage, individual cells of the embryo must not be: growing dividing responding to cytoplasmic determinants or induction
A
What is the relationship between the following terms: gametophyte, sporophte, spore, gamete. gametophytes produce gametes, which fuse and develop into sporophytes; sporophytes produce spores, which develop into gametophytes gametophytes produce spores, which develop into sporophytes; sporophytes produce gametes, which fuse and develop into gametophytes gametophtyes produce gametes, which develop into sporophytes; sporophytes produce spores, which fuse and develop into gametophytes gametophytes produce spores, which fuse and develop into sporophytes; sporophytes produce gametes, which develop into gametophytes
A
Which type of male competition would you typically expect in species with external fertilization? Male-male aggression or courtship displays Sperm competition Both Neither
A
Which of these structures is NOT formed during gastrulation? Blastocoel Archenteron Endoderm Mesoderm Ectoderm
A Gastrulation is the reorganization of the embryonic cells (blastomeres) of the blastula to create the three embryonic germlayers (endoderm, mesoderm, ectoderm). the archenteron (primitive gut) forms as a result of the movement of blastomeres into the blastocoel. the blastocoel exists prior to gastrulation as a result of cleavage, and is necessary for gastrulation to occur; without the blastocoel, there is no space for the archenteron to form.
Which of the following is a cost experienced by an individual in a promiscuous mating system? An individual experiences high risk of sexually transmitted diseases and parasites. If a male does not have an alpha ranking, he is unlikely to mate at all. The male does not ensure 'genetic insurance' by mating with multiple females. Cuckoldry is common (where a male contributes to parental care of an offspring that he is not related to).
A promiscuous mating systems enable rapid spread of parasites and sexually transmitted diseases in populations. a defining characteristic of promiscuious mating systems is that all/most males mate with all/most females, which achieves 'genetic insurance' on the part of the male that at least some of the offspring in the population will be his. it also achieves insurance on the part of the females against infanticide, as males are selected against killing offspring since they may be killing their own (the reverse occurs in polygynous mating systems, where it is adaptive for males to kill existing offspring when they take over a group previously monopolized by a different male). cuckoldry is not relevant in promiscuous mating systems, where parental care is generally performed only by females (either singly or communally).
One way embryonic cells can learn their position in an embryo is by detecting the concentration of a morphogen hormone DNA polymerase gene encoding a transcription factor
A this is the definition of a morphogen, a molecule that exists in a concentration gradient and provides spatial information to the embryonic cells based on the local concentration. some morphogens are hormones, such as auzin in plant development; some morphogens are mRNAs or proteins, such as biocoid in fruit fly development. transcription factors control what genes are activated or repressed in different cell types, and play a role in development. Genes are not present in concentration gradients.
Aquatic animals that rely on external fertilization for reproduction have a low probability of successful fertilization. Which of the following is a mechanism used to increase the liklihood of successful external fertilization? (select all that apply) courtship rituals to synchronize male/female gamete release depositing sperm into the female reproductive tract production of extremely large number of gametes that are released simultaneously containment of sperm within spermatophores
A and C
Which of the following is/are TRUE of the fertilization envelope? Select all that apply. The fertilization envelope is the physical structure responsible for the slow block to polyspermy. The fertilization envelope prevents dehydration of the fertilized egg. The fertilization envelope arises as a result of the acrosomal reaction. The fertilization envelope is the same thing as the jelly layer. The fertilization envelope forms when the vitalline layer lifts away from the egg plasma membrane None of these are true.
A and E
Which of the following is/are true of pollen and embryo sacs (select all that apply): They are gametophytes They are sporophytes They are stages in the angiosperm life cycle that produce gametes They are stages in the angiosperm life cycle that produce spores They are multicellular They are single-celled Pollen is single-celled; the embryo sac is multicellular
A, C, and E
Match each structure with its function in sexual reproduction of angiosperms
Anther - Specific structure that contains micropsorocyte, including meiosis and pollen grain development Carpel - Contains all structures related to "female" part of angiosperm Filament - Stalk linking anther to flower Ovary - Specific structure that contains megasporocyte, including meiosis and ovule development Petal - Attract pollinators Stamen - Contains all structures related to "male" part of angiosperm Sepal - Protect the developing flower bud Stigma - Structure that receives pollen Style - Stalk that links stigma to ovary Pollen grain - The male gametophyte Embryo sac - The female gametophyte
As an animal gets larger, which of the following occurs? Its surface area grows more rapidly than its volume. Its volume grows more rapidly than its surface area. Its volume and surface area increase in proportion to each other. Its volume increases, but its total surface area decreases.
B
Cells of mammalian embryos remain totipotent (can turn into any type of cell in the adult body) until the 16-cell stage. This means you can remove any individual cell from a mammalian embryo up to the 16 cell stage, and the individual cell will undergo normal development to become a normal organism. (This is how identical twins arise.) How does this compare with what you know about amphibian embryos such as the Xenopus embryo previously described? It is pretty much the same It is pretty different What?
B
During the follicular phase, secretion of _______ causes maturation of the ______. progesterone; corpus luteum. FSH; ovarian follicle. LH; ovarian follicle. estrogen; corpus luteum. none of these
B
Follicle stimulating hormone (FSH) and leutinizing hormone (LH) are important hormones involved in regulating the female reproductive cycle, but not in males. True False
B
In humans spermatogenesis and oogenesis differ in a number of ways. Which of the following is NOT one of them? number of functional gametes produced by a single meiosis event ploidy of final meiotic products timing of meiotic divisions (when they occur in the male/female life cycle) number of gametes produced in a given time period all of these are differences between human male and female gametogenesis
B
In humans, fertilization normally occurs on the surface of the ovary, at ovulation within the oviduct, after ovulation within the uterus, just prior to implantation within the uterus, immediately post-implantation none of these
B
The primary function of the corpus luteum is to stimulate the development of the mammary glands maintain progesterone levels after ovulation has occurred support pregnancy in the second and third trimesters nourish and protect the egg cell none of these
B
What is the relationship between a sporocyte and a spore? sporocytes develop into megaspores; spores develop into microspores sporocytes are cells that divide to produce spores sporocytes are the multicellular, diploid stage of the plant that produce spores spores differentiate into sporocytes
B
Which of the following ensures species-specific fertilization? Enzymes in the acrosome Bindin proteins in sperm membrane Cortical granules within the egg Cytoplasmic determinants in the egg
B
Which of the following is FALSE? Multicellularity allows organisms to become larger than physiologically possible for a single cell Cell volume places an upper limit on cell surface area In a multicellular organism, all cells must be exposed to either the environment or a circulatory system Adaptations that increase surface area, such as invagiations or flattened cell shape, allow cells to become larger Development and cell specialization is a consequence of multicellularity All of these are true All of these are false
B
What would be the phenotype of a Drosophila mutant embryo that contained twice the normal levels of Bicoid in a concentration gradient across the embryo? It would have two posteriors. Structures normally found only at the anterior end would also develop in more posterior locations. Structures normally found only at the posterior end would also develop in more anterior locations. It would develop normally.
B Bicoid is a morphogen, a molecules that works via concentration gradient to influence cell identity; cells determine where they are along the body axis (and thus what type of cell they shoudl become) based on the concentration of morphogen they are exposed to. High concentrations of bicoid causes cells to recognize that they are at the anterior (head) end of the embryo. If bicoid were twice as concentrated, across the embryo, then cells would be exposed to higher levels of bicoid across the entire length of the embryo. This would mean that cells toward the middle of the embryo would be exposed to biocoid levels normally present only at the anterior end, and thus resulting in structures that are normally only in the anterior end of the embryo to be present farther toward the posterior of the embryo.
There are populations of snails in New Zealand that can produce sexually or asexually. The snails are parasitized by a type of worm, which is a major stressor to the snails. Given what you know about conditions that favor sexual or asexual reproduction, you would expect to see the snails produce asexually when: there are many parasitic worms in the environment there are few parasitic worms in the environment
B because asexual reproduction is faster than sexual reproduction, asexually reproducing organisms have a huge advantage of sexually reproducing organisms when conditions are favorable; if the asexual organisms are well-adapted to the environment, they will quickly out-compete sexually reproducing organisms. sexual reproduction offers a better advantage in rapidly changing environments, unfavorable conditions, or in the presence of pathogens and parasites, due to increased opportunities for genetic recombination. the presence of parasitic worms would favor sexual reproduction because the worms would rapidly adapt to the asexually reproducing snails who only have mutation as a means of genetic diversity; sexually reproducing snails have mutation and genetic recombination as sources of genetic diversity.
Sporocytes divide by meiosis to create spores. What is different between the microsporocyte and megasporocyte in angiosperms? The ploidy of the spores produced. The number of surviving spores. Whether the spores develop into unicellular or multicellular gametophytes.
B meiosis always involve two cellular divisions to go from 2n to 1n, and it always produces cells with half the ploidy of the original parent cell. the defining feature of alternation of generations is that there is both a multicelluar diploid stage AND a multicellular haploid stage; plant spores always develop into multicellular gametophtes (pollen and the embryo sac, in the case of angiosperms). in the case of the microsporocyte, four surviving pollen grains are produced (four gametophytes.) in the case of the megasporocyte, only one spore survives to become the embryo sac.
Fertilization in all animal species results in formation of a fertilization envelope which: Prevents the zygote from dehydrating Prevents more sperm from fertilizing the same egg Permits the egg to implant in the uterine wall
B polyspermy is prevented first by the short-lived fast block (egg membrane depolarization) and the long-lived slow block caused by separation of the vitelline envelope from the egg plasma membrane; once the vitelline envelope lifts away from the plasma membrane, it is called the fetilization envelope. the zygote is protected from dehydration by the amnion of the amniotic egg (in amniotes) or by being laid in water in non-amniotes. implantation in the uterine wall only occurs in placental mammals, and is mediated by the extra-embryonic tissues of the blastocyst.
What is the significance of the archenteron? It will become the mesoderm It will become the digestive tract It initiates gastrulation It will become the blastopore
B the archenteron results from invagination of cell into the blastocoel during gastrulation. it is the privitive gut which will become the digestive tract, and is the beginning of the 'tube within a tube' organization of most animal body plans. the archenteron is lined with endoderm (inner tissue layer), while the mesoderm is between the endoderm and the ectoderm (outer tissue layer). gastrulation initiates at the blastopore, which is the site where endodermal cells begin transit into the blastocoel.
The highest peak in the diagram below shows? estrogen triggering ovulation LH triggering ovulation FSH supressing menstruation estrogen promoting endometrial growth progesterone suppressing menstruation
B the blue line
Which structure develops into fruits? Seeds Ovaries Ovules Flowers Stems Endospores Carpels
B the ovary, which contains the ovules, which contain the embryo sac (female gametophyte), develops into a fruit if double fertilization and early embryonic development into a mature seed is successful. ovaries are located at the base of the carpel.
Which of the following is a "cost" associated with sexual reproduction? other than mutation, no new genetic diversity in the next generation requires time/energy to find/court mate only females can produce offspring disruption of beneficial allele/trati combinations none of the aboves are costs associated with sexual reproduction
B, C, and D
Which of the following is/are true of Hox genes? they control the locations of specific parts of the body plan of plants and animals, such as the locations of eyes, limbs, or leaves they are evolutionarily conserved in all animals except sponges they activate expression of genes which control development of body segments they are chemical signals present in the unfertilized egg changes in Hox genes has contributed to rapid diversification of animal lineages
B, C, and E Morphogens are present in concentration gradients in the unfertilized egg. Hox genes are far down the cascade of events that play a role in development, and are ultimately activated much later in development as a result of genes which were activated by genes which were activated by genes which were activated by (etc.) the original morphogen. Hox genes also are not present in concentration gradients. Hox genes control segment identity in animals, specifying where eyes, legs, etc. should develop; they are evolutionarily conserved in all animals except sponges (thus a synapomorphy in all animals excelt sponges). Evolution of different animal groups closely (but does not completely) correlated with duplications in Hox genes, suggesting they are an important contributor to speciation events in animal lineages. Hox genes are not present in plants; MADS box genes play an analagous role in plant development, though MADS box genes and Hox genes are not evolutionarily related.
In a species where females typically mate with multiple males (select all that apply): there is no competition between males males likely compete indirectly with each other through sperm competition for successful fertilization of a female's eggs males likely compete directly with each other for the opportunity to male with a female males may have elaborate penis morphologies or large ejaculate volumes females may have the ability to preferentially use sperm from a specific male
B, D, and E
In species that reproduce via external fertilization: males do not have to compete with each other for access to a female's eggs only females provide parental investment, in the form of the nutrition present in the egg sexual selection does not operate sperm and egg encounter each other outside of the female's body, typically in an aquatic environment none of these
D
After ovulation (in the luteal phase), high levels of _ ___ _ inhibit secretion of _ ___ _. FSH and LH ... estrogen and progesterone HCG ... estrogen and progesterone progesterone ... FSH and LH estrogen ... FSH
C
During ejaculation, sperm cells are transported away from the testis into the abdominal cavity via the: seminiferous tubules. Sertoli cells. vas deferens. prostate gland. epididymis.
C
How does "the pill" work to prevent pregnancy? It produces a thickened mucus to impede sperm. It is a barrier between the vagina and the cervix. It delivers progesterone causing the ovary to discontinue ovulating a new oocyte. It blocks the oviduct, preventing passage of eggs or sperm.
C
In vertebrate animals, spermatogenesis and oogenesis differ in that oogenesis begins at the onset of sexual maturity, whereas spermatogenesis begins during embryonic development oogenesis produces four functional haploid cells, whereas spermatogenesis produces only one functional spermatozoon cytokinesis is unequal in oogenesis, whereas it is equal in spermatogenesis spermatogenesis is not completed until after fertilization occurs, but oogenesis is completed by the time a girl is born
C
Reproduction from an unfertlized egg is called Budding Fragmentation Parthenogenesis Sexual reproduction
C
What is a cost to the female in a polygynous mating system? little opportunity to mate with a genetically fit male high risk of contracting sexually transmitted diseases little help from male in caring for offspring high competition between females for access to males
C
What is the relationship between ovule, ovary, and seed? Ovules contain ovaries; ovaries become seeds after they are fertilized Seeds contain ovules; ovules become ovaries after they are fertilized Ovaries contain ovules; ovules become seeds after they are fertilzed Seeds contain ovaries; ovaries become ovules after they are fertilized Ovules contain seeds. seeds become ovaries after they are fertilized Ovaries contain seeds; seeds become ovules after they are fertilized
C
Which of the following best demonstrates the relationships between the different developmental processes? Cell differentiation is the major driver of the other developmental processes Cell proliferation, on its own, can result in substantial changes to embryo shape In the absence of induction, most of the other developmental processes would be severely impaired or not occur Programmed cell death usually only occurs when needed to eliminate defective cells in an embryo
C
Which of the following does NOT represent a form of parental investment? a spermatophore containing nutrients eaten by a female insect a male fish mouthbrooding eggs abandoned by a female a copulatory plug deposited in the reproductive tract of a female mouse a female bird incubating externally-laid eggs all of the above represent a form of parental investment
C
If the chorion were removed from an amniotic egg, what would happen to the embryo inside? The embryo would suffer from lack of water. The embryo would suffer from lack of nutrients. The embryo would have difficulty respiring. The embryo would have nowhere to excrete waste. The embryo would develop normally.
C Amnion - fluid filled cavity that provides aqueous environment and cushions against mechanical shock; Yolk sac - nutrients - blood vessels transport nutrients from yolk to embryo; Chorion - gas exchange between embryo and air; Allantois - waste disposal sac, also functions with chorion in gas exchange
In species that are capable of both sexual and asexual reproduction, under which of the following conditions is sexual reproduction more likely to occur? when males and females find each other when conditions for survival are favorable when conditions for survival are unfavorable cannot be determined: the conditions favor sexual over asexual remains a complete mystery.
C because asexual reproduction is faster than sexual reproduction, asexually reproducing organisms have a huge advantage of sexually reproducing organisms when conditions are favorable; if the asexual organisms are well-adapted to the environment, they will quickly out-compete sexually reproducing organisms. sexual reproduction offers a better advantage in rapidly changing environments, unfavorable conditions, or in the presence of pathogens and parasites, due to increased opportunities for genetic recombination.
Ongoing communication via a diverse set of chemical signals best describes which of the five essential developmental processes? cell differentiation cell proliferation programmed cell death induction cell movement and differential expansion
D
If an egg distributed all the constituents of its cytoplasm uniformly (eg, no cytoplasmic determinants or asymmetric yolk distribution), which of the following outcomes is most likely? all daughter cells will die all daughter cells will move to new locations all daughter cells will express the same set of genes
C cytoplasmic determinants are asymmetrically located throughout the egg genome. cytoplasmic determinants are transcriptional regulators and thus control blastomere fate by altering transcription in the blastomeres that contain them. if cytoplasmic determinants where distributed equally throughout the egg, then they would not provide different instructions to different blastomeres during early development, and thus all blastomeres would transcribe the same sets of genes as each other. in fact there are many maternally-deposited molecules which ARE distributed evenly throughout the egg, but these molecules do not function as cytoplasmic determinants specifically because they are present equally in all blastomeres.
Which of the following is NOT true of cytoplasmic determinants? They are asymmetrically distributed across the unfertilized egg They are usually mRNAs or proteins They originate from the embryonic genome They arre distributed unequally in different blastomeres as a result of cleavage
C cytoplasmic determinants have two defining features: they are asymmetrically located throughout the egg (for example, in a concentration gradient across the egg), and they are deposited from the MATERNAL genome. they are not derived from the embryonic genome. cytoplasmic determinants are typically mRNAs or proteins derived from the maternal genome. tissue-specific proteins are transcribed later on during embryonic development, from the embryonic genome, as part of cell differentiation (becoming specialized cell types). if cytoplasmic determinants where distributed equally throughout the egg, then they would not provide different instructions to different blastomeres (cells resulting from cleavage) during early development. in fact there are many maternally-deposited molecules which ARE distributed evenly throughout the egg, but these molecules do not function as cytoplasmic determinants specifically because they are present equally in all blastomeres.
As cleavage progresses, individual cells in the embryo: Get larger Stay constant in size Get smaller Differentiate
C during cleavage, the embryo stays the same size. in order for this to occur, the cells in the embryo divide without growing between cell divisions, and thus they get smaller with every division. differentiation, the process of becoming a specialized cell time, occurs much later in embryonic development.
Gametes are produced by [blank] in the haplontic life cycle, by [blank] in the diplontic life cycle, and by [blank] in the alternation of generations life cycle. mitosis; mitosis; mitosis mitosis; mitosis; meiosis mitosis; meiosis; mitosis mitosis; meiosis; meiosis meiosis; meiosis; meiosis meiosis; mitosis; meiosis meiosis; mitosis, mitosis
C gametes are always haploid, regardless of the ploidy of the organism that produces them. if the organism is haplid (haplontic life cycle), then the only cellular process to make haploid cells is mitosis, because mitosis creates cells which are identical to the parent cell. if the organism is diploid (diplontic life cycle), then the only cellular process to make haploid cells is meiosis, because meiosis reduces ploidy by half. in alternation of generations, the diploid organism produces haploid spores (via meiosis) which grow into haploid multicellular organisms. these haploid multicellular organisms produce gametes via mitosis.
The mature, multicellular organism is [blank] in the haplontic life cycle, [blank] in the diplontic life cycle, and [blank] in the alternation of generations life cycle. diploid; haploid; diploid haploid; diploid; haploid haploid; diploid; there is a haploid and a diploid at different stages there is a haploid and a diploid at different stages; diploid; haploid haploid; there is a haploid and a diploid at different stages; diploid there is a haploid and a diploid at different stages; haploid; diploid diploid; there is a haploid and a diploid at different stages; haploid diploid; haploid; there is a haploid and a diploid at different stages
C gametes are always haploid, regardless of the ploidy of the organism that produces them. if the organism is haplid (haplontic life cycle), then the only cellular process to make haploid cells is mitosis, because mitosis creates cells which are identical to the parent cell. if the organism is diploid (diplontic life cycle), then the only cellular process to make haploid cells is meiosis, because meiosis reduces ploidy by half. in alternation of generations, the diploid organism produces haploid spores (via meiosis) which grow into haploid multicellular organisms. these haploid multicellular organisms produce gametes via mitosis.
The surgical removal of one oviduct would Decrease the time between ovulation and implantation. Decrease the number of eggs produced by the ovary. Prevent half of a woman's eggs from reaching the uterus.
C oviducts connect the ovaries to the uterus. in general, ovaries alternate between production of mature follicles (eggs). in the absence of one oviduct, the ovaries would each continue to alternate producing eggs; however, the eggs produced in the 'disconnected' ovary would not be able to reach the uterus.
What is the selective advantage for a male to participate in a polyandrous mating system? He is more likely to obtain more mates than if he did not cooperate. He cannot outcompete other males for female attention. His offspring are unlikely to survive without his parental care. He cannot provide any parental care.
C polyandry is rare and the ecological factors that favor it typically involve very low survival rates of offspring such that females must constantly reproduce in order for any offspring to survive. this means females are not available to raise the young, as they would be unable to produce additional young if they had to care for an existing brood or clutch. therefore in polyandry there is typically a "role reversal" between males and females in terms of rearing young. females abandon the nest (jacana birds) or transfer eggs to the male's brood pouch (pipefish). thus the offspring only survive (and the male ensures reproductive success) only if he cares for them. in polyandry, females compete for access to males. a male who cannot outcompete others for access to females is only likely to successfully mate in true monogamy or promiscuity mating systems.
The primary ovarian hormone(s) responsible for maintaining the uterine lining following ovulation is/are (select all that apply): FSH LH Estrogen Progesterone Testosterone Inhibin
D
Undescended testes in a human male probably results in infertility because he cannot produce sperm through meoisis. the sperm do not have flagella the testes are not close enough to the vas deferens for the sperm to cross the gap the temperature is too warm for the sperm to swim the pH is too acidic for the sperm
D
Which of the following supports development/maintenance of a polygynous system? The female(s) control access to resources and maintain multiple mini-territories. Males and females form groups based on non-mating hierarchies and social contexts. The females(s) aggregate for communal offspring care, and the male(s) exploit these groupings for reproductive pursuits. Breeding success is low without combined efforts by more than one individual.
C polygynous mating systems require the capacity for a single male to 'monopolize' a group of females; this means that a) the females must all be in one location and b) they cannot all be sexually receptive at the same time. if they are not all located in the same place (ie, resources are scattered, multiple mini-territories), then other males can mate with some of the females when the primary male is not near them. if the females are all sexually receptive at the same time, then other males can mate with females while the primary male is mating with another. in species with low breeding success, multiple males often mate with a single female. in species that aggregate in groups including both males and females, a single male cannot monopolize all females due to the presence of other males.
What is the role of the calcium signal in the egg? Ensure species-specific fertilization Release enzymes to digest sperm bindin proteins Release proteases to digest bindin receptors on egg Attract sperm to the egg
C sperm-egg membrane fusion causes a Ca2+ wave under the egg plasma membrane. this reaction initiates fusion of cortical granules, which lie just under the egg membrane, with the egg plasma membrane. these cortical granules release the digestive enzymes into the space between the egg plasma membrane and the vitilline layer, where they digest the sperm bindin receptors that allow the sperm to bind the egg. once these receptors are degraded, the vitelline envelope separates from the egg plasma membrane, causing the the slow block to polyspermy by making it impossible for additional sperm to reach the egg plasma membrane. species-specific fertilization is mediated by the sperm bindin and receptor molecules on the egg that recognize the sperm bindin molecules. (each species has different versions of bindin and bindin receptors.)
During fertilization, the acrosome _____. prevents polyspermy by releasing enzymes that destroy surrounding sperm nourishes sperm mitochondria, increasing sperm motility digests the coatings surrounding the plasma membrane of the egg injects the sperm nucleus into the egg during fertilization Answer
C the acrosome is a compartment in the sperm that contains digestive enzymes. contact between the sperm and the jelly layer/zona pellucida initiate release of the digestive enzymes which degrade the jelly layer. polyspermy is prevented by the short-lived fast block (egg membrane depolarization) and the long-lived slow block caused by separation of the vitelline envelope from the egg plasma membrane. sperm mitochondria are nourished by component of the semen such as citric acid and sugars. the sperm nucleus enters the egg upon membrane fusion between egg and sperm.
The results of the Xenopus experiment described in the powerpoint best support which biological conclusion? The first cell division can be manipulated. Presence or absence of yolk determines the success of development. The gray crescent contains cytoplasmic determinants important for proper development of dorsal structures. The gray crescent contains cytoplasmic determinants necessary for proper development of ventral structures.
C the formation of the 'belly piece' embryo from the portion of the fertilized egg which lacks any gray crescent material indicates that these cells lacked the ability to form any dorsal (back) structures. the instructions for dorsal structures were present in the gray crescent prior to fertilization, and thus qualify as cytoplasmic determinants. presence/absence of yolk was not manipulated in this experiment. the first cell division can be artificially manipulated, but this is not the biologically-meaningful finding from this experiment.
Which of these choices represents a major difference between the reproductive cycles of plants and humans? Humans produce gametes (sperm and eggs); plants produce spores. The reproductive cycle of humans involves haploid and diploid phases; that of plants involves only haploid phases. Human gametes are formed by meiosis, and plant gametes are formed by mitosis. Meiosis occurs in humans but not in plants. Human spores develop into sperm or eggs, and plant spores develop into seeds.
C the gametes produced by plants are called eggs and sperm, just as in animals. the reproductive cycle of all sexually-reproducing organisms involves a haploid and diploid cycle; in humans, the haploid portion is only the gametes, while in plants, the haploid cycle includes the spores, the gametophte, and the gametes. meiosis produces sperm and eggs in humans, and spores in plants. in eukaryotes, a spore is a haploid cell that is capable of developing into a multicellular, adult organism; humans do not make spores.
Which of the following is gametophyte tissue (is produced by the gametophyte)? Anther Stigma Pollen tube Sepal Fruit Integument
C the male gametophyte is pollen (contains the tube cell and the generative cell), the female gametophyte is the embry sac (contains the egg, polar nuclei, synergids, and antipodal cells). the pollen tube grows from the tube cell in the pollen through the style of the flower to reach the ovule, which contains the female gametophyte. thus the pollen tube is gametophyte tissue. flowers are sporophyte tissue. the stigma is the part of the flower that the pollen grain adheres to; the sepals are leaf-like structures that contain and protect the flower bud while it is developing; the integument is the sporophyte tissue within the ovule immediately surrounding the female gametophte. the fruit developes from the ovary. ovaries contain ovules which contain the female gametophte. thus fruits are also sporophyte tissue.
Which of the following is NOT a developmental process that explains the relationship beteween the notochord, somites, and limb muscles? induction proliferation differential expansion cell movement differentiation all of these describe the relationship between somites and limb development
C the most immediate structure required for limb muscle development is the somites; cells in the somite migrate to the limbs where they proliferate to develop into muscles, so removal of somites would prevent development of muscles. the somites arise and become specified for certain celll fates due to a combination of signals from the notochord, the dorsal ectoderm, and the neural tube. cells of the notochord secrete signals which induce folding of the dorsal ectoderm to form the neural tube. somites then form along side the neural tube after it is formed. differential expansion is a developmental process that occurs only in plants.
Which of the following explains why females are more likely to be "choosy" about mating partners than males? Females are more limited in the number of offspring they can produce than males are Eggs require more energy to produce than sperm Males can fertilize the eggs of multiple females, while a female's egg can only be fertilized by a single male All of these
D
What effect would surgical removal of the seminal vesicles have on the human male reproductive system? It would cause sterility because sperm would not be produced. It would cause sterility because sperm would not be ejaculated from the body. Semen would not contain energy-providing nutrients for the sperm. Sperm would exit the body in urine.
C the seminal vesicles produce fructose and prostaglandins added to semen immediately prior to ejaculation; fructose is a source of chemical energy for sperm movement, and prostaglandins stimulate smooth-muscle contractions in the uterus to aid sperm movement into the oviducts. sperm are produced in the seminiferous tubules within the testes, and stored in the epididymis. any disruption in the transport pathway from the epididymis out of the body would prevent sperm from being ejaculated; this pathway consists of the vas deferens, the ejaculatory duct (where accessory fluids are mixed with the sperm), and finaly the urethra, the shared urogenital tube that transports semen or urine out of the body.
If you were to view a sample of animal tissue under a light microscope and notice an extensive extracellular matrix surrounding a tissue, which tissue type would you most suspect? Epithelial Striated muscle Connective Nervous
C this is part of the definition of connective tissue: connective tissue by definition consists of cells arranged in either a liquid (like blood), jelly-like (like fat tissue), or solid extracelluar matrix (like tendons, bone, or cartilage). Epithelial tissues consist of tightly-packed, sheet-like layers of cells that line organs or the body surface. Nervous tissue consistes of nerve cells and their supporting cells. Muscle tissue consists of bundles of long, thin, contractile cells.
Two flowers are both brightly colored and only open during the day, but flower A is highly scented and flower B is not. Flower A is most likely pollinated by an animal pollinator; flower B by wind Flower A is most likely pollinated by a bird; flower B by an insect Flower A is most likely pollinated by an insect; flower B by a bird Both flowers could be pollinated by either an insect or a bird Both flowers could be pollinated by either wind or an animal
C •Birds: active during day, respond to visual stimuli •Bees/butterflies/wasps: active during day, respond to visual and olfactory stimuli •Moths: active during night, respond to visual and olfactory stimuli •Bats: active during night, respond to visual and olfactory stimuli
Asexual reproduction by budding is represented by: one arm of a starfish breaking off and forming a new individual starfish a single-celled diatom undergoing mitosis and cytokinesis to form two new equally sized daughter cells. a single-celled yeast undergoing mitosis and unequal cytokenisis to grow a small new cell that will break off to become a daughter cell a bacteria undergoing binary fission to create two new daughter cells a multicellular hydra growing a small new multicellular hydra that will break off to form a new, independent hydra a lizard's unfertilized egg developing into a new adult
C and E
Which of the following is typically predictive of second-male advantge in mating? lekking copulatory plug mate guarding large testes and ejaculate volume none of these are predictive of second-male advantage
D
The developmental behavior demonstrated by the cells of the AER and ZPA is best described as differential expansion movement proliferation induction programmed cell death differentiation
D AER causes cells to grow distally away from the body, elongating the limb. ZPA specifies the anterior/posterior axis, causing development of different digits toward the posterior vs anterior side of the limb. the limb appears to be mirror-imaged, where it has normal organization but doubled as if it were an ink blot folded in half. the length of the limb suggests that AER was functioning correctly in causing cells to proliferate distally away from the body. the mirror-image suggests that there were two ZPA regions, each causing formation of posterior digits on both sides of the limb.
If the allantois were removed from an amniotic egg, which of the following would be primary outcome for the embryo? The embryo would suffer from lack of water. The embryo would suffer from lack of nutrients. The embryo would not be able to exchagne gases. The embryo would not be able to extrete wastes. The embryo would develop normally.
D Amnion - fluid filled cavity that provides aqueous environment and cushions against mechanical shock; Yolk sac - nutrients - blood vessels transport nutrients from yolk to embryo; Chorion - gas exchange between embryo and air; Allantois - waste disposal sac, also functions with chorion in gas exchange
Which structure produces signaling molecules that induce neural tube formation? Somites Coelom Mesoderm Notochord
D cells of the notochord secrete signals which induce folding of the dorsal ectoderm to form the neural tube. the notochord is mesodermal in origin, but it is specifically the notochord and not mesodermal cells in general that induce formation of the notochord. somites form along side the neural tube after it is formed. the coelum, or body cavity, does not contain cells and does not secrete signals during development.
Which of the following directors of embryonic development can be found within unfertilized eggs of protostomes? mRNAs transcribed from embryonic genome bindin proteins tissue-specific proteins cytoplasmic determinants
D cytoplasmic determinants have two features: they are asymmetrically located throughout the egg (for example, in a concentration gradient across the egg), and they are deposited from the MATERNAL genome. they are not derived from the embryonic genome. cytoplasmic determinants are typically mRNAs or proteins derived from the maternal genome. tissue-specific proteins are transcribed later on during embryonic development, from the embryonic genome, as part of cell differentiation (becoming specialized cell types). bindin proteins are present on mature sperm and are used to mediate sperm-egg binding during fertilization.
An ovary contains 20 ovules. Each ovule contains an egg and an endosporm, each of which must be fertilized by a sperm cell. How many pollen grains are required in order for all 20 ovules to develop into viable seeds with embryos and endosperm? Ten, since each pollen tube produces two sperm. Forty, since double fertilization requires two pollen to fertilize each embryo sac. One, since pollen tubes can release more than one sperm. Twenty, since each pollen tube releases two sperm. Two, since one pollen tube will release sperm and the other will release eggs.
D double fertilization refers to an angiosperm-specific phenomenon where two sperm are required to create the seed: one sperm fertilizes the haploid egg to create the diploid zygote (embryo) itself, while the other sperm fertilizes the two polar nuclei to produce the triploid endosperm. The endosperm grows into nutritive tissue which is then metabolized by the growing embryo. the pollen tube grows from the tube cell in the pollen grain (the male gametophyte) through the style of the flower to reach the ovule, which contains the female gametophyte. the generative cell in the pollen grain produces two sperm; thus one pollen grain produces the two sperm required to accomplish double fertilization.
Double fertilization is a component of the angiosperm life cycle, and produces: the pollen tube and ovules the endosperm and pollen tube the zygote and pollen tube the zygote and endosperm
D double fertilization refers to an angiosperm-specific phenomenon where two sperm are required to create the seed: one sperm fertilizes the haploid egg to create the diploid zygote (embryo) itself, while the other sperm fertilizes the two polar nuclei to produce the triploid endosperm. The endosperm grows into nutritive tissue which is then metabolized by the growing embryo. the pollen tube is part of the male gametophyte (pollen); it grows from the pollen grain on the flower stigma through the flower style to reach the ovary. the two sperm travel through the pollen tube to reach then female gametophyte (embryo sac which contains the egg and polar nuclei) inside the ovule. the ovule is the structure inside the ovary which contains the female gametophyte (embryo sac).
As cleavage progresses, the cells of the embryo _____ and the whole embryo ______. get larger; gets larger stay constant in size; stays constant in size stay constant in size; gets larger get smaller; stays constant in size get smaller; gets smaller none of these
D during cleavage, the embryo stays the same size. in order for this to occur, the cells in the embryo divide without growing between cell divisions, and thus they get smaller with every division. differentiation, the process of becoming a specialized cell time, occurs much later in embryonic development.
One way embryonic cells can learn their position in an embryo is by engaging in the process of cell differentiation or differential expansion cell proliferation programmed cell death induction from adjacent cells
D each of these process can be a response to a cell knowing its location in an embryo, and each of them can be caused by induction (cell-cell communication)
In mammals, identical twins are produced by the separation of cells during gastrulation organogenesis pattern formation blastomere cleavage the development of the notochord
D in order for a cell to be capable of forming a new organism, it must not yet be 'specified' for a specific cell fate (ie, becoming a skin cell, or an anterior part of the body, or ectoderm, etc). at gastrulation (and of course later on in development), cell-fate differences have already been established. thus identical twins can only form from cells prior to gastrulation, during cleavage. this phenomenon is true of organisms that do not use cytoplasmic determinants in the egg to specify cell fate. if cytoplasmic determinants are present, and the very first cell division causes unequal partitioning of the cytoplasmic determinants, then cells can already have cell-fate-specific information during the first blastomere cleavage.
What is the selective advantage for a male to participate in a polyandrous mating system? He is likely to attract a greater number of mates. He cannot provide any parental care. He cannot outcompete other males for female attention. His offspring are unlikely to survive without his care. None of these.
D polyandry is rare and the ecological factors that favor it typically involve very low survival rates of offspring such that females must constantly reproduce in order for any offspring to survive. this means females are not available to raise the young, as they would be unable to produce additional young if they had to care for an existing brood or clutch. therefore in polyandry there is typically a "role reversal" between males and females in terms of rearing young. females abandon the nest (jacana birds) or transfer eggs to the male's brood pouch (pipefish). thus the offspring only survive (and the male ensures reproductive success) only if he cares for them. in polyandry, females compete for access to males. a male who cannot outcompete others for access to females is only likely to successfully mate in true monogamy or promiscuity mating systems.
Fertilization of a human egg takes place in the _____. cervix uterus ovary oviduct vagina
D sperm can survive in the oviduct for ~3-4 days. fertilization must in the oviduct immediately after ovulation. the cleavage divisions occur in the oviduct as the fertilized egg moves toward the uterus.
Cells of mammalian embryos remain totipotent (can turn into any cell in the adult body) until the 16-cell stage. This suggests that mammalian embryos: Have large amounts of evenly-distributed yolk Take longer to go through the cleavage cell divisions than other animals Do not have induction Do not have cytoplasmic determinants
D the fact that any mammalian blastomere up to the 16-cell stage can become a normal embryo indicates that the blastomeres do not have 'restricted cell fate.' this means they do not have specific changes in their gene expression to make them different from any other blastomere. this scenario would be impossible if mammalian cells had cytoplasmic determinants, because cytoplasmic determinants (by definition) are asymmetrically located throughout the egg genome and control blastomere fate by altering transcription in the blastomeres that contain them. in the absence of cytoplasmic determinants, all blastomeres would transcribe the same sets of genes as each other. in fact there are many maternally-deposited molecules which ARE distributed evenly throughout the egg, but these molecules do not function as cytoplasmic determinants specifically because they are present equally in all blastomeres. mammalian eggs actually have very small amounts of yolk, which is evenly distributed (consistent with the phenomenon discussed here). speed of development or cell division is irrelevant here: if there are cytoplasmic determinants, then it doesn't matter how quickly or how slowly the cells in an egg divides; ultimately they will end up with different genes expressed if there are cytoplasmic determinants present in the egg. finally, cell-cell signaling is central to development in ALL organisms, and take over the processes of development after cytoplasmic determinants cease playing a role in later development. in the absence of cytoplasmic determinants at all (as in the case of mammalian eggs), then cell-cell communication plays an even more important role in initiating differences between cells during development.
Which of the following plays a role in cells "knowing" where they are in an embryo and thus what type of cells they should become (differentiate into) during development? cell proliferation programmed cell death cell movement or differential expansion cell-cell signaling/induction cytoplasmic determinants
D and E cytoplasmic determinants set up initial identity/location information in many lineages including protostomes and some vertebrates. cytoplasmic determinants are important early in development during cleavage, but they are quickly 'titrated out' in later development, when cell-cell signaling (induction) becomes much more important in establishing identity/location information. the other developmental processes (movement, proliferation, programmed cell death) are all regulated by cell-cell signaling
An advantage of asexual reproduction is that it allows an individual to easily eliminate harmful mutations allows the species to endure long periods of unstable environmental conditions produces offspring that respond effectively to new pathogens enhances genetic variability in the species enables the species to rapidly colonize new habitats that are favorable to that species
E
Which of the following is NOT an example of parental investment? A male fish holds fertilized eggs in his mouth until they hatch to protect them from predators A female mammal produces milk for her offspring A male praying mantis is eaten by a female during mating, and the proteins from his body are deposited into the eggs she produces after mating with him A female bird sits on a nest to incubate eggs A male fish guards a female after mating with her, preventing other males from mating with her all of these are examples of parental investment
E
Monogamy is more likely to occur in a species with external fertilization. a species where females control access to resources. a species where females aggregate for social reasons. a species with a high degree of female parental care. a species that lives in a habitat with very scattered resources.
E monogamy typically occurs when a) care by both parents is required for survival of the offspring and b) males do not have opportunity to mate with multiple females. these situations occur when resources are highly scattered, such that females are not located in the same place (which would enable a male to mate with multiple females) and both parents must take turns acquiring food to feed the offspring.
Females of many insect species, including honeybee queens, can store gametes released by their mating partners in _____. their nests the cloaca the abdominal tract the uterus the spermatheca
E this is the definition of the term spermatheca. spermathecas are present in many invertebrate species such as insects, worms, and some molluscs. females in some species have multiple spermathecas which can store sperm from a single or multiple males, allowing fertilization of eggs for months after a single mating. sperm from the spermatheca fertilizes the egg as it passes through the oviduct
Spores are produced [blank] in the haplontic life cycle, [blank] in the diplontic life cycle, and [blank] in the alternation of generations life cycle. by mitosis; by mitosis; by mitosis by mitosis; by mitosis; by meiosis by mitosis; by meiosis; by mitosis by mitosis; by meiosis; by meiosis by meiosis; by meiosis; by meiosis by meiosis; by mitosis; by meiosis by meiosis; by mitosis; by mitosis by meiosis, are not produced; by meiosis by mitosis; are not produced; by mitosis are not produced; are not produced; by meiosis are not produced; are not produced; by mitosis
H spores are always haploid, and are always produced meiosis. in the haplontic life cycle, the diploid zygote immediately undergoes meiosis to produce haploid spores. the haploid spores grow into a mature, multicellular, haploid adult. this haploid adult produces gametes via mitosis. in alternation of generations, the diploid organism produces haploid spores (via meiosis) which grow into haploid multicellular organisms. these haploid multicellular organisms produce gametes via mitosis. there are no spores produced in the diplointic life cycle. the diploid zygote develops into a mature, muticellular organism which produces gametes by meiosis.
Match the tissue type to its description, function, or example:
Muscle - contract to facilitate movement; may be voluntarily or involuntarily controlled Epithelial - tightly aligned cells that create barriers between internal and extranal biological compartments; cells may be different shapes based on location/function Nervous - transmit both chemical and electrical signals Connective - composed of a matrix of living cells and non-living substances; blood is one example
Rank the following mating systems from least to most selection for sperm competition. (ie, from the system where you would expect to see the LEAST sperm competition to the system where you would expect to see the MOST sperm competition). If two systems would be expected to have about the same amount of sperm competition, use the equal sign. Polygyny Promiscuity True monogamy Social monogamy
Polygyny = True monogamy < Social monogamy < Promiscuity there should be minimal selection for sperm competition where females only mat with a single male; in this case the male who mates with the female is 'ensured' paternity and is unlikely to be selection for traits that enhance competition among sperm. in polygyny and true monogamy, females only ever mate with a single male. in social monogamy, females 'mostly' mate with one male, but also occasionally mate with other males; thus there is some selection for traits that enhance competiton among sperm. in promiscuity, females mate with many males, and thus there is strong selection for traits that enhance sperm competition.
Rank the following mating systems from least to most selection for sperm competition. (ie, from the system where you would expect to see the LEAST sperm competition to the system where you would expect to see the MOST sperm competition). If two systems would be expected to have about the same amount of sperm competition, use the equal sign. Polygyny Promiscuity True monogamy Social monogamy
Polygyny = True monogamy < Social monogamy < Promiscuity there should be minimal selection for sperm competition where females only mate with a single male; in this case the male who mates with the female is 'ensured' paternity and is unlikely to be selection for traits that enhance competition among sperm. in polygyny and true monogamy, females only ever mate with a single male. in social monogamy, females 'mostly' mate with one male, but also occasionally mate with other males; thus there is some selection for traits that enhance competiton among sperm. in promiscuity, females mate with many males, and thus there is strong selection for traits that enhance sperm competition.
Rank the following mating systems from least to most selection for sexual dimorphism. (ie, from the system where you would expect to see the LEAST sexual dimorphism to the system where you would expect to see the MOST sexual dimorphism). If two systems would be expected to have about the same amount of sexual dimorphism, use the equal sign. Polygyny Promiscuity True monogamy Social monogamy
True monogamy = Promiscuity < Social monogamy < Polygyny there should be minimal selection for sexual dimorphism where every male has equal chance of mating, as females are not discriminating among males prior to mating. in promiscuity and true monogamy, females every male is 'guaranteed' a mate and thus there is no competition among males for access to females. in social monogamy, some females will seek out extra-pair-copulations (mate with males that are not their social partner). thus females are selecting males based on certain cues (for example, as in the good genes hypothesis) which will cause some selecting for sexual dimorphism. in polygynous mating systems, only a single male will mate with females, causing very strong selection for sexual dimorphism for male-male competition and female choice.
what structure secretes progesterone to nourish the uterine lining?
progesterone is secreted from the corpus luteum following ovulation. the corpus luteum is located in the ovary, and is composed of the cells remaining from the ruptured follicle after the egg has matured and left the ovary. progesterone stimulates production of the uterine lining in anticipation of fertilization and embryo implantation. in the absence of fertilization and successful embryo implantation, the corpus luteum degenerates over time, ceasing production of progesterone and causing the uterine lining to shed. if fertilization and successful embryo implantation occurs, then the embryo secretes a hormone that prevents the corpus luteum from degrading to maintain the early pregnancy. once the placenta is formed, it takes over progesterone production to maintain the pregnancy.
Place the following events in order, where "event 1" < "event 2". Assume all steps occur sequentially, meaning you should never use the = symbol. the egg membrane depolarizes the acrosome reaction occurs the fertilization envelope lifts sperm binds the zona pellucida/jelly layer a wave of calcium proceeds throughout the cell cortical granules fuse with the plasma membrane, initiating the cortical reaction the sperm membrane fuses with the egg membrane
sperm binds the zona pellucida/jelly layer < the acrosome reaction occurs < the sperm membrane fuses with the egg membrane < the egg membrane depolarizes < a wave of calcium proceeds throughout the cell < cortical granules fuse with the plasma membrane, initiating the cortical reaction < the fertilization envelope lifts
What part of male anatomy is targeted during a vasectomy, and why does the procedure successfully block male fertility?
the vas deferens is severed and tied off/sealed; prevents sperm from reaching the urethra
In which step is there a spike in LH and FSH?
there is a small, gradual increase in FSH (follicle stimulating hormone) throughout the follicular phase to promote development of the follicle (egg). thre is a small spike in FSH and a large spike in LH (lutenizing hormone) that causes ovulation. ovulation is the event which marks the shift from the follicular phase (follicle maturation) to the luteal phase (dominated by progesterone production from the corpus luteum in anticipation of pregnancy).
