Keystone Review Module 2 PPT

8/10/2019 Keystone Review Module 2 PPT

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Keystone ReviewModule B


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BIO.B.1.1 Describe the three stages of thecell cycle: interphase, nuclear division,cytokinesis.

Describe the events that occur during thecell cycle: interphase, nuclear division,and cytokinesis.

Compare the processes and outcomes ofmitotic and meiotic nuclear division.


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Which statement BEST describes the phaseof the cell cycle shown?

A. The cell is in prophase ofmitosis because thenumber of chromosomeshas doubled.

B. The cell is in prophase I ofmeiosis because of thenumber of chromosomeshas doubled.

C. The cell is in telophase ofmitosis because the cell isseparating and containstwo copies of eachchromosome.

D. The cell is in telophase ofmeiosis because the cell is

separating and containstwo copies of each


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Answer - C A. Incorrect - The cell is not in prophase. This

is obvious as the cell contains two nuclei, acondition which only occurs in telophase.

B. Incorrect - The cell is not in prophase. Thisis obvious as the cell contains two nuclei, acondition which only occurs in telophase.

C. Correct - The cell is in telophase, which canbe seen from the two nuclei. Onlytelophase of mitosis includes two copies ofeach chromosome.

D. Incorrect - The cell is in telophase, but inmeiosis each cell contains only 1 copy ofeach chromosome.


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Answer - D

A. Incorrect both mitosis and meiosisare both multi-step processes

B. Incorrect mitosis occurs in both

prokaryotic and eukaryotic cellsC. Incorrect meiosis produces

gametes, it is not involved in therepair of organisms.

D. Correct mitosis producesgenetically identical cells; meiosisproduces genetically different cells.


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Patau Syndrome can be a lethal geneticdisorder in mammals, resulting fromchromosomes failing to separate during

meiosis.Part A: Identify the step during the process

of meiosis when chromosomes wouldmost likely fail to separate.

Part B: Describe how chromosomeseparation in meiosis is different fromchromosome separation in mitosis.

Part C: Compare the effects of a disordercaused by chromosomes failing toseparate during meiosis, such as Patausyndrome, to the effects of chromosomes

failing to separate during mitosis.


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Identify the step during the process of meiosiswhen chromosomes would most likely fail toseparate. Anaphase I or II are the most likely steps in

which chromosomes would fail to separate.During Anaphase I, homolgous chromosomesare pulled to opposite sides of the cell. If thespindle fibers do not attach properly duringmetaphase, the homologous pairs will notseparate correctly. If the homologous pairsdo not separate, two will go into one cell.

Anaphase II is the phase in which sisterchromatids are pulled to opposite sides of thecell. If sister chromatids fail to separate, twowill go into one gamete. If this gamete werefertilized it would result in a trisomy, such as


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Describe how chromosome separation inmeiosis is different from chromosomeseparation in mitosis.

There are two divisions within meiosis,meiosis I and meiosis II. Duringmeiosis I, chromosomes line up in

homologous pairs in order for the cellto be reduced from diploid to haploid.They then line up end to end inmeiosis II in order to separate sisterchromatids.

In mitosis, chromosomes separate onlyonce. They line up end to end. Thisresults in two identical, diploid cells.


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chromosomes failing to separate duringmeiosis, such as Patau syndrome, to theeffects of chromosomes failing to separateduring mitosis.When a mutation occurs during meiosis, the

organism in which the mutation occurs is not

affected. However, the disorder will bepassed to their offspring. Since all the cells inthe offspring begin with the two parentalgametes, every cell in the body of theoffspring will contain the mutation.

When a mutation occurs during mitosis, theorganism in which the mutation occurs isaffected. However, the mutation will only

occur in the localized region in which themutated cell is found. It cannot be passed to


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Which event most likely occursnext in mitosis?

A. The chromatin condenses.B. The nuclear envelope dissolves.

C. The chromosomes double in number.D. The cell membrane pinches inward todivide the cytoplasm.


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Answer - D

A. Incorrect - The condensing of thechromatin occurs during prophase at thebeginning of mitosis.

B. Incorrect - The nuclear envelopedissolves after the chromatin condensesinto chromosomes during prophase.C. Incorrect - The chromosomes double innumber during the S phase, not duringmitosis.D. Correct: The next event would showtelophase, when the cell begins to separateinto two daughter cells.


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Mitosis and meiosis are processes by which animaland plant cells divide. Whichstatement best describes a difference betweenmitosis and meiosis?

A. Meiosis is a multi-step process.B. Mitosis occurs only in eukaryoticcells.

C. Meiosis is used in the repair of anorganism.D. Mitosis produces genetically identical

daughter cells.


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Answer - D

A. Incorrect - Both meiosis and mitosis aremulti -step processes.B. Incorrect - Mitosis also takes place in

prokaryotic cells.C. Incorrect - Meiosis generates gametesused in sexual reproduction.D. Correct - Cells produced through mitosiscontain DNA identical to the parent cells,whereas meiosis produces cells that arehaploid and often genetically different.


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Bio.B.1.2 Explain how geneticinformation is inherited. Describe how the process of DNA

replication results in the transmissionand/or conservation or genetic

information. Explain the functional relationships

between DNA, genes, alleles, andchromosomes and their roles ininheritance.


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What process helps to preserve the geneticinformation stored in DNA during DNAreplication?

A. The replacement of nitrogen basethymine with uracil.

B. Enzymes quickly linking nitrogen

bases with hydrogen bonds.C. The synthesis or unique sugar and

phosphate molecules for eachnucleotide.

D. Nucleotides lining up along thetemplate strand according to basepairing rules.


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Answer: D

A. Incorrect DNA replication creates DNA,uracil is used only in RNA

B. Incorrect Nitrogen bases are linked withhydrogen bonds created by enzymes, butthis is not what preserves geneticinformation.

C. Incorrect the genetic information in DNA isstored in the order of the base pairs, not inthe sugar or phosphate.

D. Correct The template strand provides theenzymes with the correct nucleotide order.The order of the nucleotides is how thegenetic information is store.


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In a flowering plant species, red flower color isdominant over white flower color. What is thegenotypes of any red-flowering plant resulting fromthis species?

A. Red and white alleles present on onechromosome

B. Red and white alleles present on two

chromosomesC. A red allele present on both

homologous chromosomesD. A red allele present on at least one

of two homologous chromosomes.


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Answer - D

A. Incorrect only one allele for each traitis present on each chromosome.

B. Incorrect since white alleles are

recessive, their presence is irrelevant. An organisms would be red if it had onered and one white allele, or two red andno white alleles.

C. Incorrect only one red allele is neededsince red is dominant.D. Correct Since red is dominant, only

one chromosome needs a red allele inorder for the plant to have red flowers.


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BIO.B.2.1 Compare Mendelian and non-Mendelian patterns of inheritance.

Describe and/or predict observedpatterns of inheritance (i.e. dominant,recessive, co-dominance, incomplete

dominance, sex-linked, polygenic, andmultiple alleles). Describe processes that can alter

composition or number ofchromosomes (ie. Crossing-over,nondisjunction, duplication,translocation, deletion, insertion, and

inversion)


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Genotype(s) Phenotype

ii OIAIA, IAi A

IBIB, IBi B

IAIB AB

A. phenotypes O or AB. phenotypes A or ABC. phenotypes A, B, ABD. phenotypes O, A, B, AB


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Answer: D

A. IncorrectB. IncorrectC. Incorrect

D. Correct all blood types arepossible. In all instances, an A or Oallele could possibly have beenpassed to the child and combine withthe A allele from the father.

A l f i ll (f l ) i h


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A cattle farmer genetically crosses a cow (female) with awhite coat with a bull (male) with a red coat. The resultingcalf (offspring) is roan, which means there are red and whitehairs intermixed in the coat of the calf. The genes for coatcolor in cattle are co-dominant.

A. What cross would produce only roanoffspring.

B. Explain how a roan calf results from onewhite- and one red-coated parent. INyour explanation, use letters torepresent genes. Be sure to indicate

what colors the letters represent.C. Predict the possible genotypes and

phenotypes of the offspring producedfrom two roan cattle.


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A. Answer: White and red

B. A white parent and a red parentwould produce all roan offspring.Roan offspring are all heterozygous,

containing one red and one whiteallele. Red cows are homozygous forred alleles- RR. White cows arehomozygous for white alleles -WW.Therefore, a red and a white cowwould produce all heterozygous (RW),roan offspring.


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C. Answer

Roan cows would produce 25% redcows (RR), 50% roan cows (RW), and25% white cows (WW)


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Answer: D

A. Incorrect a deletion involves theremoval of a gene or genes from thechromosome.

B. Incorrect an insertion involves addinggenes to a chromosome

C. Incorrect an inversion involvesrearranging genes on one chromosome

D. Correct this image shows two differentsized chromosomes, indicating non-homologous chromosomes. A portion ofone is being switched with a portion ofthe other. This is the definition of


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A scientist observes that a certain trait is determined by a singleallele. An organism inherited one version of the trait from oneparent and another version from the other parent. Both versions ofthe trait are expressed in the phenotype of the offspring. Whichpattern of inheritance best classifies the observed trait?

A. dominance

B. sex-linkageC. co-dominanceD. incomplete dominance


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Answer - C

A. Incorrect - The pattern of inheritance does notreflect that one allele is dominant and the other isrecessive since both traits are expressed in theindividual.

B. Incorrect - The information given does notprovide enough evidence for a sex-linkage patternof inheritance.C. Correct - The pattern of inheritance is best

described as co-dominance because both traits arefully expressed in the phenotype of the individual.D. Incorrect - Since both versions of the trait areexpressed without a modification of the phenotypeexpressed, the pattern of inheritance is notincomplete dominance.


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BIO.B.2.2 Explain the process of proteinsynthesis (i.e. transcription, translation, andprotein modification). Describe how the processes of

transcription and translation aresimilar in all organisms.

Describe the role of ribosomes,endoplasmic reticulum, Golgiapparatus, and the nucleus in theproduction of specific types ofproteins.

Which statement describes a cell process that is common to both


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Which statement describes a cell process that is common to botheukaryotic and prokaryotic cells?

A. Both cell types carry out transcription in the nucleus.B. Both cell types use ribosomes to carry out translation.

C. Both cell types assemble amino acids to carry out transcription.D. Both cell types carry out translation in the endoplasmic reticulum.


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Answer - B

A. Incorrect prokaryotes lack anucleus

B. Correct both prokaryotes and

eukaryotes carry out translation onribosomes.C. Incorrect transcription does not

involve amino acidsD. Incorrect prokaryotes lack

endoplasmic reticulum.

The endoplasmic reticulum is a network of membranes within the cell,


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The endoplasmic reticulum is a network of membranes within the cell,and it is often classified as rough or smooth, depending on whetherthere are ribosomes on its surface. Which statement best describesthe role of rough endoplasmic reticulum in the cell?

A. It stores all proteins for later use.B. It provides an attachment site for larger organelles.C. It aids in the production of membrane and secretory proteins.D. It stores amino acids required for the production of all proteins.


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Answer - C

A. Incorrect the endoplasmicreticulum is not a storage organelle.

B. Incorrect ribosomes, which are

small organelles, attach to rough ERC. Correct ribosomes are housed on

the rough ER. This is wheretranslation occurs.

D. Incorrect ER is not a storageorganelle

The bacterium Acetobacter aceti is found in acidic environments and has an


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The bacterium Acetobacter aceti is found in acidic environments and has anacidiccytoplasm. For this reason, most of its proteins are able to function in acidicconditions. This property distinguishes Acetobacter aceti proteins from those ofmost other organisms. Which characteristic does Acetobacter aceti most likely

share with other organisms?

A. the method that the organism uses to reproduce itself B. the physical and chemical responses to environmental changesC. the type of organelle used to produce energy for cellular functionsD. the process used to form proteins by transcription and translation


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Answer - D

A. Incorrect - Bacteria are prokaryotes andreproduce by binary fission; most organismsthat are eukaryotes reproduce by mitosis andmeiosis.B. Incorrect - Bacteria are prokaryotes, lackingmembrane-bound organelles, which respond tochanges in their environment differently thaneukaryotic cells.C. Incorrect - Bacteria are prokaryotes and donot have membrane-bound organelles, such asmitochondria that produce energy for eukaryoticcells.D. Correct - Prokaryotes and eukaryotes both


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BIO.B.2.3 Explain how geneticinformation is expressed. Describe how genetic mutations alter

the DNA sequence and may or maynot affect phenotype (e.g. silent,

nonsense, frameshift)

A genetic mutation resulted in a change in the sequence of amino


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g g qacids of a protein, but the function of the protein was not changed.Which statement best describes the genetic mutation?

A. It was a silent mutation that caused a change in the DNA of the

organism.B. It was a silent mutation that caused a change in the phenotype of

the organism.C. It was a nonsense mutation that caused a change in the DNA of the

organism.D. It was a nonsense mutation that caused a change in the phenotype

of the organism.


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Answer - A

A. Correct silent mutations changethe genetic code of the DNA, but donot result in changes to the protein

function. Therefore, the phenotypeof the organism is not affected.B. Incorrect a silent mutation by

definition does not changephenotype

C/D. Incorrect a nonsense mutationtotally destroys protein function

A mutation occurs at the midpoint of a gene


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A mutation occurs at the midpoint of a gene,altering all amino acids encoded after the point ofmutation. Which mutation could have produced thischange?

A. deletion of two nucleotidesB. deletion of three nucleotidesC. insertion of six nucleotides

D. insertion of twelve nucleotides


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Answer - A

A. Correct - A deletion of two nucleotides will most likelycause a shift in the codon sequence that codes for anamino acid. This could cause a change in the sequenceof amino acids attached after the point of themutation.B. Incorrect - A deletion of three nucleotides will cause adeletion of the original amino acid in the protein but willnot cause a change in the rest of the amino-acidsequence.

C. Incorrect - An insertion of six nucleotides will add twoadditional amino acids to the protein but will not cause achange in the rest of the amino-acid sequence.D. Incorrect - An insertion of twelve nucleotides will addfour additional amino acids to the protein but will notcause a change in the rest of the amino-acid sequence.

f


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BIO.B.2.4 Apply scientific thinking, processes,tools, and technologies in the study ofgenetics. Explain how genetic engineering has

impacted the fields of medicine,forensics, and agriculture (e.g.

selective breeding, gene splicing,cloning, genetically modifiedorganisms, gene therapy)

Genetic engineering has led to genetically modified plants that resist


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insect pests and bacterial and fungal infections. Which outcome wouldmost likely be a reason why some scientists recommend caution inplanting genetically modified plants?

A. unplanned ecosystem interactionsB. reduced pesticide and herbicide useC. improved agricultural yield and profitD. increased genetic variation and diversity


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Answer - A

A. Correct genetically modified plants mayspread their genes to wild plants duringpollination, which cannot be controlled in theoutdoor environment. This may result in genes

for resistance being spread into ecosystems,causing unintended results.B. Incorrect this type of genetic engineering

reduces the use of pesticides and herbicides,but this is a positive effect.

C. Incorrect increasing resistance to pests wouldincrease yields, but this is a reason to plantthese plants.

D. Incorrect increased genetic diversity

increases survival of a species and is a positive


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BIO.B.3.1 Explain themechanisms of evolution. Explain how natural selection can

impact allele frequencies of apopulation.

Describe factors that can contribute tothe development of new species (e.g.isolating mechanisms, genetic drift,founder effect, migration).

Explain how genetic mutations mayresult in genotypic and phenotypicvariations within a population.

In North America the eastern spotted skunk mates


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In North America, the eastern spotted skunk matesin late winter, and the western spotted skunk matesin late summer. Even though their geographicranges overlap, the species do not mate with eachother. What most likely prevents these two speciesfrom interbreeding?

A. Habitat isolationB. Gametic isolationC. Geographic isolationD. Reproductive isolation


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Answer D

A. Incorrect these skunks share a geographicrange and likely share habitat. Habitat isolationinvolves species which share a range but notthe same habitat

B. Incorrect gametic isolation generally refers tospecies which send out gametesindiscriminately, such as pollen of trees

C. Incorrect geographic isolation involves twospecies whose ranges do not overlap

D. Correct all of these choices are reproductiveisolation. These skunk species mate atdifferent times, which is an example of temporalisolation. This is the best answer as temporal

isolation is a type of reproductive isolation.

A t ti i th th t d f


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A mutation occurs in the genes that code forcoat color in deer. Which change will mostlikely result from this mutation?

A. A change in the selection pressuresacting on coat color.

B. A change in the coat-color genes of

deer predator speciesC. An increase in coat-color diversity inthe population

D. An increase in the number of genesfor coat color in the population.


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Answer - C

A. Incorrect an additional coat color genewould not change selection pressures.

B. Incorrect a change in deer coat colorwill have no effect on the coat color ofpredator species

C. Correct an additional gene for coatcolor will definitely change the coat color

diversityD. Incorrect a mutation will increase thenumber of alleles for the gene, but willnot create an entirely new gene


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BIO.B.3.2 Analyze the sources ofevidence for biological evolution. A) Interpret evidence supporting the

theory of evolution (i.e. fossil,anatomical, physiological,

embryological, biochemical, anduniversal genetic code.


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The skeletons of mammalian forelimbs represent variationsof a structure that was present in their common ancestor.What has most likely caused the variation in forelimbs?

A. Changes inmusclestructure

B. Changes in thegenetic codeC. Trait formation

due tobehaviors

D. Development ofvestigial

structures


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Answer - C

A. Incorrect changes in muscle structure wouldnot cause the variation in forelimbs. It is morelikely bone structure changes would occur first.

B. Correct changes in the genetic codes would

be needed to make a change in phenotype.C. Incorrect- the only traits that can be inheritedare those that an organism is born with,therefore changes due to behaviors would notresult in skeletal changes. For example, if youdye your hair green, you will not give birth togreen-haired children.

D. Incorrect vestigial structures are those thatare present, but no longer used, in organisms.

All of these organisms use their forelimbs.

The gene COII is in the genome of many organisms.


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The gene COII is in the genome of many organisms. A comparison of the number of base differencesbetween the COII gene in a rat and that of two otheranimals is shown.

Animal Number of base differences from a ratMouse 101

Cow 136

Part A: Based on the data, describe a possible evolutionaryrelationship between rats, mice, and cows.

Part B: Describe how different organisms having a common genesuch as COII supports the theory of evolution.

Part C: The COII gene of a monkey has 203 base differences fromthe same gene in a rat and 201 base differences from the same genein a mouse. Compare the evolutionary relationships between themonkey, the rat, and the mouse.


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Answers

Part A: Mice and rats are more closelyrelated than rats and cows. This canbe seen from the smaller number of

differences in the COII protein.Part B: Different organisms would nothave the same gene by chance. If twoorganisms share a gene, it is likelythat they shared a common ancestorwho passed the gene on to eachspecies.


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Part C

A rat and a mouse are more closelyrelated to each other than to amonkey. They have only 101 base

difference for the COII protein. The mouse is more closely related to

the cow than the rat, with a differenceof 201 bases rather than 203.

The frequency of an allele in a fly population


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q y y p pchanges from 89% to 20% after three generations.Which other events most likely occurred during thesame time period?

A. an environmental change and a flypopulation increaseB. an environmental change and a fly

population decreaseC. interbreeding of flies with an invasivespecies and fly population speciation

D. interbreeding of flies with anestablished local species and flypopulation speciation


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Answer - B

A. Incorrect - An environmental change that did not favor theindividuals in the population with the allele most likely led to thechange in allele frequency; however, since the allele frequencydecreased by so much, there would had to have been adecrease in the population within a three-generation period oftime.B. Correct - An environmental change that did not favor theindividuals in the population with the allele most likely led to thechange in allele frequency; since the allele frequency decreasedby so much, there would had to have been a decrease in thepopulation within a three-generation period of time.C. Incorrect -Interbreeding between species is not likely to occurand can produce off spring that are not able to reproduce.Speciation would most likely need more than three generationsto occur.D. Incorrect - Interbreeding between species is not likely to occur

and can produce off spring that are not able to reproduce.

BIO B 3 3 Apply scientific thinking processes tools


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BIO.B.3.3 Apply scientific thinking, processes, tools,and technologies in the study of the theory ofevolution.

A. Distinguish between the scientificterms: hypothesis, inference, law,theory, principle, fact, and observation.


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Answer: D

A. Incorrect this is not a testablehypothesis, it is simply a fact that thefrogs living in that pond are defined

as a population.B. Incorrect also not a testablehypothesis

C. Incorrect it is not possible to judgethe happiness of fish

D. Correct it is possible to set up anexperiment to see the response of

frogs to sudden stimuli

BIO.B.4.1- Describe ecological


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B O.B. . esc be eco og calevels of organization in thebiosphere.

A. Describe the levels of ecologicalorganization (i.e. organism,population, community, ecosystem,

biome, and biosphere).B. Describe characteristic biotic andabiotic components of aquatic andterrestrial ecosystems.

A student wrote several observations in a field


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A student wrote several observations in a fieldnotebook. Which term best classifies all of thestudents observations?

Observations: 2 grey wolves, 5 moose, severalspecies of conifer trees, large granite rock, shallowpond

A. PopulationB. Food chainC. EcosystemD. Community


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Answer: C

A. Incorrect a population is a group oforganisms belonging to the samespecies living in the same time andplace.

B. Incorrect a food chain contains onlyorganisms, not abiotic factors

C. Correct an ecosystem contains both

the biotic and abiotic factors in an areaD. Incorrect a community is all the livingspecies in a particular area at aparticular time

A researcher observing an ecosystem describes the


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amount of sunlight, precipitation, and type of soilpresent. Which factor is the researcher most likelydescribing?

A. biotic factors in a forestB. Biotic factors in a tundraC. Abiotic factors in a prairie

D. Abiotic factors in an ocean


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Answer - C

A or B. Incorrect the factors describedare abiotic, not biotic

C. Correct the abiotic factors listedinclude soil, making this the only likelyoption.

D. Incorrect the abiotic factors listedinclude soil, which is not likely to bedescribed in an ocean environment.


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Answer - D

A. Incorrect the arrows in the foodweb show the flow of energy. Energyflows from krill to penguins to seals

B. Incorrect again, this is the reverseof the energy flow shown in the diagramC. Incorrect the arrows show thatseals eat penguins, penguins do not eatsealsD. Correct the arrows show thatenergy does flow from fish to penguinsto seals.

A species of snapping turtles has a tongue that


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resembles a worm. The tongue is used to attractsmall fish. Which best describes the interactionbetween the fish and the snapping turtle?

A. PredationB. SymbiosisC. Parasitism

D. competition


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BIO B 4 2 D ib i i d


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BIO.B.4.2 Describe interactions andrelationships in an ecosystem

A. Describe how matter recycles through anecosystem (i.e. water cycle, carbon cycle,oxygen cycle, and nitrogen cycle).

B. Describe how ecosystems change in

response to natural and human disturbances(e.g. climate changes, introduction ofnonnative species, pollution, fires).

C. Describe the effects of limiting factors on

population dynamics and potential speciesextinction.D. Describe the effects of limiting factors on

population dynamics and potential species

extinction.

Whi h t t t tl d ib h


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Which statement correctly describes hownitrogen in the soil returns to the atmosphere?

A. Soil bacteria convert nitrates intonitrogen gas.

B. Decomposers directly convert

ammonium into nitrogen gas.C. Plants assimilate nitrites and convertthem into nitrogen gas.

D. Nitrogen-fixing bacteria in plant rootsconvert nitrates into nitrogen gas.


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Answer - A

A. Correct - Soil bacteria convert nitratesinto nitrogen gas in a process known asdenitrification.

B. Incorrect decomposers make nitrogenavailable to producers, but do notconvert it into gas.

C. Incorrect plants only release nitrogen

when they are decomposedD. Incorrect nitrogen fixation removesnitrogen from the atmosphere.

Agricultural runoff can carry fertilizers into lakes and


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Agricultural runoff can carry fertilizers into lakes andstreams. This runoff can cause algae populationsto greatly increase. Which effect does this change

in the algae population sizes most likely have onaffected lakes and streams?

A. An increase in water levelB. An increase in water clarityC. A reduction in dissolved oxygen

needed by fish and shellfishD. A reduction in temperature variationsnear the waters surface


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Answer - C

A. Incorrect an algal bloom will have no effecton water level

B. Incorrect an algal bloom will decreaseclarity

C. Correct algal blooms lead toeutrophication, a process in which algae dieand decompose. This leads to the removalof large quantities of oxygen to the water.

Eventually, even decomposition stops andthe body of water is filled with half-decomposed algae

D. Incorrect this would have no effect on

temperature.

A farmer observed that an increase in a fields soil


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nitrogen content was followed by an increase inproducer productivity. What does this observationmost likely indicate about the relationship betweennitrogen and the producers in the field?

A. Nitrogen was a biotic factor

B. Nitrogen was a limiting factor C. Nitrogen became a surplus resourceD. Nitrogen became a selection

pressure


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Answer - B

A. Incorrect nitrogen is an abiotic factor B. Correct a limiting factor is something required

for an ecosystem to maintain growth. When it isabsent, growth stops. In this instance, the

primary productivity increased with theapplication of nitrogen, indicating that it was thefactor preventing growth in the ecosystem.

C. Incorrect nitrogen would not have caused anincrease in productivity if it was a surplusresource.

D. Incorrect there is nothing being selected on inthis example. Selection pressure indicatesevolution, which has nothing to do with this

example.

Isle Royale is located in Lake Superior. Isle Royale ishome to populations of wolves and moose The


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home to populations of wolves and moose. Theinteractions between the wolves and moose, as well asthe individual population sizes, have been studied since

1958. The graph shows the population sizes over timefor both wolves and moose.

A. Describe one limitingfactor for the moose

population.B. Explain one likely reason

why the wolf populationrapidly increasedbetween 1975 and 1980.

C. Predict what will happento the moose populationssize after 1994 bydescribing the shape ofthe curve. In youranswer, be sure to


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Answer

A. Predation by wolves is one limiting factor. Wolveseat the moose. Other factors could include foodavailability, competition, disease, etc.

B. Immediately previous to this time, the moosepopulation dramatically increased. The moose arefood for the wolves, therefore their population alsorose.

C. The moose population will continue to increase untilthe wolf population increases or the moose run out offood. This is predicted as the wolf populationincreased, causing a drop in moose population, afterthe last moose population increase. The moose arecurrently increasing again. If the wolf populationdoes not rebound, the moose will eventually reach

carrying capacity and their population levels will even

Scientists observed that the populations of top-level


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Scientists observed that the populations of top levelconsumers in a particular ecosystem were rapidlydecreasing. Further studies revealed that there was also

a decline in producer productivity. Which other changesdid the scientists most likely observe in the ecosystem?

A. increased producer diversityB. decreased population size at all levelsC. decreased primary consumer populations

onlyD. increased primary and secondary

consumer diversity


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Answer - B

A. Incorrect - A decline in producer productivity wouldmost likely result in a decrease in producer diversity. B. Correct - A decline in the producers of an

ecosystem will cause a decrease in all otherorganisms because

the producers are responsible for converting sunlightor chemical energy into usable energy for

consumers. C. Incorrect - Primary consumer populations will

decrease, but secondary consumer populations willalso decrease.

D. Incorrect - A decline in producer productivity wouldmost likely lead to a decrease in diversity in primaryand

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