BCOR-012 Final Exam Part 2

Flashcard maker : Christine Brunetti
In Meiosis, a _____ parent cell divides to form _____ daughter cells
Diploid; 4 haploid
When do homologous chromosomes line up in a pairwise fashion on the equatorial plate during meiosis?
During metaphase 1 only
Which sequence provides a model for describing the process of meiosis
Chromosomes replicate ⇾ Homologous chromosomes separate ⇾ Cytokinesis ⇾ Sister chromatids separate ⇾ Cytokinesis
Sister chromatids present at metaphase 2 might not be genetically identical to each other because ______
Of crossing over events taking place during Meiosis 1
Independent assortment results in gametes containing _____
Many combinations of genes and parts of genes that originated from both the organism’s male or female parent
Two genes coding for proteins involved in glycolysis reside on the same chromosome. Can these genes assort independently?
Yes, with a greater chance if the genes are located far apart from one another on the chromosome
If cells with the genotype SsYyRr undergo meiosis, how many types of gametes will be produced? Assume that the genes are on different chromosomes.
8
In a pedigree analysis, a shaded circle is used to represent a _____ and a partially shaded circle is used to represent an _____
Fully affected female; unaffected female carrier
A human disease is observed to follow an autosomal dominant pattern of inheritance. If a boy diagnosed with the disease has a father who does not have the disease, what can be deduced about the boy’s mother?
She must be affected by the disease also
Tongue-rolling is a human trait that follows an autosomal recessive pattern of inheritance. A girl with the tongue-rolling trait has two brothers who do not have this trait. What is true of the children’s parents?
One parent must be heterozygous and the other is either heterozygous or homozygous recessive
A man affected by a recessive trait on the X chromosome marries a woman who neither shows the trait nor is a carrier. Which outcome is possible if they have two children-a son and a daughter?
An unaffected son and a carrier daughter
In what way did T. H. Morgan’s fruit fly data not conform to Mendel’s law of independent assortment?
In his F1 generation, Morgan observed more than the expected numbers of flies with parental phenotypes
What factor determines how often two alleles for a gene will recombine?
The physical distance that separates them on the chromosome
The gene for body color and wing shape reside on the same chromosome in fruit flies. After crossing female flies having gray bodies and normal wings with male flies having black bodies and vestigial wings, Morgan observed that some of the F1 flies had nonparental phenotypes (gray bodies with vestigial wings, or black bodies with normal wings). What accounts for this?
The alleles for wing shape and body color recombined by crossing over
What fraction of offspring of the cross Aa × Aa is homozygous for the dominant allele?
1/4
What fraction of the offspring of the cross AaBb × AaBb would show the dominant phenotypes for both genes?
9/16
Suppose unattached earlobes are a dominant trait. Phil and Maggie both have unattached earlobes but their daughter, Celia, does not. If Phil and Maggie have a second child, what is the probability that he or she will have attached earlobes?
1/4
The cross AaBb × AaBb is an example of a _____ cross; the results of such crosses led Mendel to propose what we now call the law of _____
Dihybrid; independent assortment
In a test cross, peas of an unknown genotype are crossed with peas of a known genotype. In this example, smooth peas are the unknown and wrinkled peas are the known (rr). If half of the offspring from that cross are smooth and half are wrinkled, what is the genotype of the unknown plant?
Heterozygous: Rr
The 9:3:3:1 ratio is obtained _____
Through a dihybrid cross in which the genes are on different chromosomes
_____ is the term for when heterozygous offspring have superior fitness than their homozygous parents
Heterosis
Codominance
Involves the expression of both alleles at a locus producing two different phenotypes
Incomplete dominance
Results in a phenotypic ratio of 1:2:1 in the F2 generation from a monohybrid cross
A woman of blood group A has a child with a man of blood group B. The child’s blood is type O. What are the genotypes of the parents?
Mother: IAIO; father: IBIO
Coat color in rabbits involves the effects of multiple gene interactions. If a rabbit has two recessive alleles (cc) for coat color, it is always albino no matter what the genotype of other genes involved in coat color. This is an example of _____
Epistasis
The fact that a trait such as height in humans varies over a wide range of values is due to _____
Multiple alles and the environmental influences on the expression of these genes
When a true-breeding red flower is crossed with a white flower, and all the F1 flowers are pink, this is due to _____
Incomplete dominance
Which statement about linkage of genes is false?
Genes on the same chromosome assort independently
True statements about linkage of genes
Crossing over between two linked genes can alter phenotypes of progeny; Genes on the same chromosome are said to be linked; Genes on the same chromosome that are far apart have a higher recombination frequency than those that are close together; Crossing over results in recombinant phenotypes
In many animals, including humans, sex is determined by a single _____, or by a pair of them. Both males and females have two copies of each of the rest of the chromosomes, which are called _____
Sex chromosome; autosomes
In sex-linked inheritance of a recessive gene, if a normal male and a heterozygous female carrier mated, all _____
Male offspring who receive the mutant X chromosome would show the trait
Wild-type fruit flies have red eyes. A white-eyed female fly is crossed with a red-eyed male fly. All of the females from the cross are red-eyed and all of the males are white-eyed. What type of inheritance pattern is this?
Sex-linked on X chromosome
Genes located on mitochondrial DNA are usually inherited ______
From the mother
Lateral gene transfer between individuals of a species _____
Can result in bacterial strains resistant to antibiotics
In order for natural selection to change a trait within a population, what must be true about the trait?
The trait must have a genetic basis
A study showed that the mortality risk for human babies goes up as birth weight decreases below the average. Another study shows an increase in mortality risk as birth weight increases above the average. What can be said about human birth weight?
It is a trait that is shaped by stabilizing selection
Each of the following features of a population, with the exception of one, may prevent the population from maintaining Hardy-Weinberg equilibrium. Which of the following is the exception?
The population is large
What is the sum of frequencies of all alleles for any given gene in a population?
1
Using the Hardy-Weinberg equations, determine the frequency of a homozygous recessive genotype (q2) if the frequency of the dominant allele is p = 0.8. Assume that there are only two types of alleles for this gene in the population.
0.04
In explaining what we now call evolution, Darwin often used the phrase \”descent with modification.\” Fundamental to this idea is that _____
Divergent species share a common ancestor
Mistakes in the replication of DNA _____
Provide genetic variation
Which phenomenon is not an evolutionary mechanism?
Random mating
Which evolutionary process adapts populations to their environments?
Natural selection
The frequency of one allele for a given gene locus with two alleles (A at frequency p and a at frequency q) in a population is known. Assume Hardy-Weinberg conditions hold true. Which statement is false?
The frequency of heterozygotes is given by (p + q)/N, where N is the number of individuals in the population
The frequency of an allele in a population of manatees is 0.15. If the population is at Hardy-Weinberg for this locus, what number of 600 individuals should be homozygous for this allele?
13.5
The Hardy-Weinberg equilibrium is not applicable under which condition?
Asexual reproduction
The Hardy-Weinberg equilibrium is applicable under which conditions?
Random mating; Infinite population size; No gene flow; No mutations
You discover a population of seals and find it to be at Hardy-Weinberg equilibrium with respect to the A locus. Suppose that there are two alleles at this locus and the frequency of one of those alleles (the a-6 allele) is 0.4. Of the individuals that carry at least one a-6 allele, what percent are homozygotes?
25
Which statement about selection is true?
Disruptive selection is the only type of selection that can produce a bimodal distribution
______ selection operates if individuals within a population with the smallest and largest body sizes have fewer offspring than those of average body size
Stabilizing
Suppose the size of a population of mustard plants is 6,000. According to genetic drift theory, what is the probability that a newly-arisen mutation will become fixed in this population?
1/12,000
Which statement about synonymous mutations is true?
They do not change the phenotype
A neutral mutation _____
Is fixed in a population at a rate equal to the mutation rate
A gene involved in neural development shows three times as many synonymous site substitutions than nonsynonymous ones. A likely explanation is that this gene _____
Is under purifying selection
Which observation would most seriously challenge the hypothesis that most noncoding DNA is slightly deleterious?
Species with larger population sizes have more noncoding DNA
Which statement about he genomes of organisms is false?
The total size of the genome of eukaryotes varies little from organism to organism
Sexual recombination ______
Can result in the elimination of harmful mutations
Gene families are groups of ______ genes that arose by _____ & _____
Homologous; Gene duplication; Sequence evolution
Which of the following statements is true of the parsimony method for reconstructing phylogeny?
The preferred phylogenetic tree under the parsimony method is the tree that requires the smallest number of evolutionary changes to explain the data
Which of the following types of data could be compared during the construction of a phylogenetic tree?
Base sequences of the same gene from two individuals of different species
In the experiment described in the tutorial, why did the investigators add a mutagen to the culture medium?
To increase the rate of evolutionary change in the viruses
Why did the investigators keep the identities of each virus generation a secret from the other researchers developing the phylogenetic tree?
To be sure that only the sequence information was used in the construction of the phylogenetic tree
Of the following scenarios, which would provide the best analogy for describing the process of constructing a phylogenetic tree using genetic information?
Assembling a jigsaw puzzle
A student comments that constructing phylogenetic trees must be possible for organisms with many shared characteristics such as camels and horses, but not possible for organisms with no obvious shared characteristics such as oak trees and sharks. Which statement provides the best evaluation of the student’s thinking?
The student’s thinking is flawed because oak trees and sharks can be compared using phylogenetic analysis, since all organisms share some basic genetic characteristics
The _____ of a phylogenetic tree represents the common ancestor, the _____ represent events where lineages diverged, and the _____ axis represents time. Assume that the tree is oriented as described in the textbook.
Root; Nodes; Horizontal
A _____ is any group of organisms we name, while a _____ is any _____ that consists of all the evolutionary descendants of a common ancestor
Taxon; Clade; Taxon
Which statements about traits is true?
A trait may be considered ancestral or derived, depending on the point of reference; Derived traits differ from their ancestral forms; Homoplastic traits can arise by convergent evolution; Traits may be lost by evolutionary reversal
The bones in the wings of birds and bats are _____ because they derived from a _____ ancestor, while the wings are _____ traits
Homologous; Common; Homoplastic
A sea squirt is thought to be more closely related to vertebrates than once thought because _____
Both vertebrate embryos and sea squirt larvae have notochords
Three character sets are being considered for inclusion in a phylogenetic analysis of lizards. The first (A) is fossil data on lizards from 10 to 20 million years ago. The second (B) is on a variety of mating behaviors that have been shown to be learned. The third (C) is from a few nuclear genes that have variable rates of evolution. Which is least likely useful to the analysis of phylogenetic relationships, and why?
B, because it involves learned traits
The best way to assess the accuracy of methods to reconstruct phylogenetic history is to _____
Use experimental tests of organisms with known evolutionary histories
Phylogenetic analyses of opsin pigments have allowed scientists to infer that ancestral archosaurs _____
May have been nocturnal
Suppose that mice and humans differ by 30 substitutions in their globin genes, and rats and mice differ by five substitutions. On the basis of other evidence, we know that the ancestor to humans and mice lived 84 million years ago. Assuming the molecular clock is operating, rats and mice split from each other _____ million years ago
14
A molecular clock assumes that the genes used _____
Are evolving slowly
The studies of self-incompatible (outcrossing) species of Leptosiphon illustrate _____
How phylogenetic systematics can reveal convergent evolution
In the classification system devised by Linnaeus, the names of _____ of plants end with the suffix _____, while those of animals end with _____
Families; -aceae; -idae
Which statements about biological classification is true?
Taxonomists use biological classification to show evolutionary relationships among organisms; Separate rules for classification have been established by botanists and zoologists; Classifications should be monophyletic; A monophyletic group may be removed from a phylogenetic tree with a single cut
A taxon that contains organisms that do not share a common ancestor is referred to as _____
Polyphyletic
What did the simulation demonstrate about the rate at which geographically isolated subsets of a population become reproductively incompatible?
The rate increases as the rate of genetic change increases in both subsets
What factor contributes to genetic divergence between two geographically isolated populations?
The appearance of different mutations in the two populations; Natural selection; Genetic Drift
Which of the following is a key element of the Dobzhansky-Muller model of speciation, in which two lineages diverge from a single lineage?
Incompatible alleles at different loci become fixed in the two lineages
What is allopatric speciation?
The splitting of one species into two as a result of geographic barriers
Why is genetic drift often a factor influencing speciation after a founder event?
Because founder events typically involve small numbers of individuals
A biologist has identified two groups of salamanders with very similar physical features on opposite banks of a river. Which investigative approach would help determine whether the groups are the result of allopatric speciation?
Compare the gene pools of the two populations to see if there are any alleles not shared by both groups
A student states that genetic drift was responsible for genetic divergence of picture-winged Drosophila on the Hawaiian Islands, which led to speciation. Another student states that natural selection was responsible. Evaluate these two statements based on information presented about these flies in the tutorial
Both students are correct
What is polyploidy?
The condition of having more than the normal number of chromosomes
How do allopatric and sympatric speciation differ?
Allopatric speciation involves a physical separation of groups as they form new species; sympatric speciation does not
How is an allopolyploid plant formed?
Two plants of different species interbreed to form a plant of a new species
How would you expect the rate of speciation of an allopatric case to compare to the rate of speciation of a sympatric case involving formation of allopolyploid offspring?
The allopatric case would occur at a much slower rate than the sympatric case involving allopolyploid offspring
Ernst Mayr’s biological species concept _____
Does not apply to organisms that reproduce asexually
Which statement about the morphological species concept is true?
Linneaus used one
Which species concept most emphasizes the evolutionary history of species?
The lineage species concept
The Dobzhansky-Muller model _____
Emphasizes gene interaction
In the Dobzhansky-Muller model, an ancestral population (aabb) splits into two lineages. Different mutations produce different new alleles in each population (Aabb in one population, aaBb in the other). All of the following genotypes would be viable except _____
AaBb
True statements about speciation
Gene flow within a population must be interrupted for speciation to occur; The Dobzhansky-Muler model is based on a minimum of two gene loci; Chromosomal rearrangements can lead to speciation; Reproductive isolation may take millions of years
Which of the following is least likely to lead to allopatric isolation?
A small lake dividing a population of butterflies
Geographic isolation _____
Geographic barrier, genetic divergence, reproductive isolation
Darwin’s finches on the Galápagos Islands have diverged primarily via _____ speciation, and exhibit diverse morphologies owing to differences in _____
Allopatric; This diets
A butterfly is separating into two different groups—one that lays eggs in the understory of bushes and the other that lays eggs in the tops of bushes. This butterfly species is most likely experiencing _____
Symmetric speciation
What statement about polyploidy in plants is true?
Allopolyploids are hybrid plants that result from the mating of two closely related species
The distinction between pre zygotic and post zygotic isolation is whether _____
The isolation occurs before or after fertilization
Two geographically separated populations of butterflies begin to diverge in the time of day they are active. One group is active earlier in the day, and the other is active later. If this separation were to continue, it would most likely contribute to _____ isolation
Temporal
Pre zygotic isolating mechanisms can arise from all the following _____
Evolution of the structure of sexual organs; Specific interactions of plants with insect pollinators; Mate selection behaviors; Differences in mating periods
Suppose that the natural ranges of horses and donkeys were to overlap. Which of the following statements best describes what would likely happen to the populations over time?
Because their hybrid offspring are not reproductively fit, reinforcement could strengthen prezygotic barriers
Two populations that were once isolated come into contact. Which of the following statements about what might happen after contact is true?
If reproductive isolation is not complete, the two populations could interbreed; Hybrids, if fit, could spread through both populations, resulting in gene flow between them; If reproductive isolation had been established before contact, the two populations could not interbreed; Hybrid zones that last for long periods of time could develop
Which are most likely to evolve via direct natural selection?
Temporal isolation; Mechanical isolation; Behavioral isolation; Habitat isolation
Persistent hybrid zones, like those found in Bombina frogs in Europe, stay narrow due to _____
Low hybrid adult viability
Where does a mosquito pick up the Plasmodium falciparum parasite?
From an infected human
Why is a mosquito an efficient vector for transmitting Plasmodium falciparum to humans?
Because mosquitoes contact human blood with their mouth parts
Human to human transmission of Plasmodium falciparum is not observed. Why?
The infecting organism must pass through part of its life cycle in another host
What was the origin of all chloroplasts?
A single cyanobacterium
Which phrase could be used in a description of secondary endosymbiosis?
A eukaryote engulfing a eukaryote
What would a biologist look for in order to determine whether a chloroplast in a cell evolved as the result of primary endosymbiosis or secondary endosymbiosis?
The number of membranes in the chloroplast
Based on information provided in the tutorial, which of the following pairs of organisms has the closest evolutionary relationship?
Green algae and land plants
According to genetic evidence, two main lines of descent emerged from the last universal common ancestor. One of these lines gave rise to the _____
Bacteria and Archaea
Why were ribosomal RNA molecules (rRNA) so important in showing the relationships between organisms in the three domains?
Because rRNA is basic to all cells and its sequence reveals phylogenetic information
Consider the following series of strata in undisturbed sedimentary rocks:
(1) Richmond is found below Talos and above Pitts; (2) Pitts is found above Somas; (3) Garett is above Talos. Based upon the principles of stratigraphy, where would you be most likely find the oldest fossils?
Somas
The ratio of 14C to its stable isotope, (12C), is relatively constant in living organisms and their environment, however, this ratio changes once an organism dies. In a fossil less than 50,000 years old you would expect the ratio of 14C to 12C to be _____
Lower, because the 14C is not replenished after death
The half-life of 14C, a radioactive element of carbon, is approximately 5,000 years. The ratio of 14C to 12C in a fossil 25,000 years old would be about _____ that of a living organism today
1-32
Which would be the best way to determine the absolute age of a collection of sedimentary rocks that are thought to be between 50 and 200 million years old?
Paleomagnetic dating
Scientists divide geological time into eras and periods. The _____ is most inclusive, and the boundaries are based on _____
Era; changes on fossils
Plates of Earth’s crust
Can move via continental drift
The increase in the concentration of CO2 in Earth’s atmosphere over the past 100 years _____
Is primarily caused by the burning of fossil fuels by humans
In the process of _____, the _____ oceanic plate is forced _____ continental plate
Subduction; Thinner; Under
Which group of organisms has been most affected by periods of increased glaciation?
Marine life
What led to the mass extinction at the end of the Cretaceous period?
A meteorite striking Earth
Which of the following about oxygen is true?
It made aerobic metabolism possible
What is the most likely result of increased oxygen concentration on insects?
Increase in body mass
For every described currently living species of organism, there are about _____
fossil species
1/6
The Cambrian explosion took place over _____ years
More than 50 million
Coal is the fossilized remains of _____
Tree ferns and horsetails
Mass extinctions occurred at the end of each of the following periods except the _____
Silurian
In the _____ period, fishes diversified and evolved jaws and club mosses, horsetails, and tree ferns became common. The earliest fossil terrestrial vertebrate and insects date from this period and there was a mass extinction at the end of the period that may have been caused by meteorite impacts
Devonian
Over geologic time, the concentration of O2 in Earth’s atmosphere has increased. During the end of the _____ period, the O2 concentration decreased significantly and resulted in _____
Permian; Mass extinction
Gondwana is _____
The southern part of the supercontinent after it broke in two
Around 5 million years ago, Earth was in the _____ era, and the _____ period
Cenozoic; Tertiary
Where does meiosis take place in the moss life cycle?
In the sporangium at the time of spore formation
Where does fertilization take place in the moss life cycle?
In the archegonium of the gametophyte generation
Which set of terms represents a haploid/diploid pair?
Spore/sporophyte
In conifers, male gametophytes are called _____ and are formed by the division of microspores
Pollen
Which statement describes events leading to formation of offspring in the conifer life cycle?
A haploid sperm from pollen enters the female gametophyte and fuses with a haploid egg
How do the sporophyte and gametophyte generations compare in a conifer?
The sporophyte generation is much larger than the gametophyte generation and the two generations grow in a single individual
Double fertilization, which is a hallmark of angiosperm sexual reproduction, results in a _____
Diploid zygote and a triploid endosperm
Which statement correctly describes the general pattern of the alternation of generations in angiosperms?
The sporophyte generation (2n) produces spores (n) that produce gametophytes (n) that produce gametes (n) that fuse to produce a new sporophyte (2n)
Which structure is not a part of the sporophyte generation?
Egg
A biologist discovers a seed-bearing plant that has never been classified. Which feature will help him determine whether the plant is a gymnosperm or an angiosperm?
Female structures that produce an egg enclosed in a protective structure
Which of the following clades does not include algae?
Embryophytes
Which of the following is a nonseed vascular plant?
Fern
Which of the following characteristics is shared by all land plants?
Alternation of generations
The sporophyte generation _____
Extends from the zygote through the adult diploid plant
Which feature for obtaining water and minerals comes after the nonvascular plants in a phylogeny of the land plants?
Extensive root systems
he dominant stage of the life cycle of a moss is the _____
Haploid gametophytes
Which statement regarding vascular plants is true?
The tracheid is the principal water-conducting element of the xylem in all vascular plants except the angiosperms
Both club mosses and horsetails _____
Have simple leaves
Which of the following statements regarding the two leaf types (microphylls and megaphylls) is true?
Microphylls arose from small, sterile sporangia
What might be the advantage of seeds with a dormant but viable state?
Insuring the continuity of the species through time
All seed plants ____
Are heterosporous
Seed Plants _____
Produce spores by meiosis within the sporangia
A female conifer cone is made up of modified _____ and a male cone is made up of _____ along a central axis. The megastrobilus cone contains the _____ gametophytes and the microstrobilus, the _____ gametophytes.
Branches; Modified leaves; Female; Male
Coniferous gymnosperms, such as pines, depend primarily on _____ for pollination, thus the plants produce large quantities of pollen that disperse over large areas during the spring
Wind
How do angiosperms differ from gymnosperms?
Angiosperms flower; gymnosperms do not
You examine two flowers of the same species but from two separate plants. One flower has only stamens, while the other flower has only a pistil. You would conclude that the species is _____, and the flowers are _____
Dioecious; Imperfect
To determine how a flowering plant is pollinated, which structure or feature would be most important to examine?
Morphology of the corolla
Which of the following correctly pairs a fruit and with a fruit type?
Pear-Accessory
Which of the following statements about seeds is true?
All seeds rely on animals for their dispersal; All seeds are fleshy and edible; All types of seeds are found in only gymnosperms; All seeds are brightly colored
How do monocots and eudicots differ?
They differ in the number of cotyledons their seeds contain
Rhizomes stolonifer _____
Has two distinct mating types
Which is a correct sequence in the life cycle of Rhizopus stolonifer?
+ and – nuclei fuse → zygosporangium → sporangia → spores
A biologist is working on classifying a structure that she believes to be either a spore or a zygosporangium from a zygosporous fungus. What can the biologist do to make the distinction?
Determine whether the structure is haploid or diploid
A student comments that a fungus such as Rhizopus stolonifer could go for many generations without ever carrying out meiosis, but not without carrying out mitosis. Evaluate the accuracy of this statement
The statement is accurate
Fungi possess all of the following traits except _____
Cell walls containing peptidoglycan
Unicellular fungi _____
Are also called yeasts
The body of a multicellular fungus is called a _____. It is made up of _____ that may be septate or ______
Mycelium; hyphae; coenocytic
Which statement about fungal nutrition is true?
Fungi can break down cellulose and keratin
In what way do fungal decomposers contribute to Earth’s carbon cycle?
They return carbon atoms to the atmosphere in the form of respiratory CO2
Lichens are _____
Most often a unicellular green alga in association with fungal cells
Which of the following could be a photosynthetic partner of a lichen?
Cyanobacterium
A mycorrhizal association provides a plant with _____ and _____, and the fungus with _____ and _____
Water; minerals; sugars; amino acids
Using a microscope, you are examining a cross section of a plant root in which hyphae surround the plant cells but do not penetrate them. You are most likely looking at _____
Ectomycorrhiza
Both endophytic fungi and mycorrhizae _____
Are important in plant growth
Reproduction in fungi _____
Can occur asexually in unicellular fungi by budding
Sexually-reproducing fungi reproduce without distinct male and female structures because they _____
Express genetically distinct different mating types instead of male and female structures
Which of the following characteristics is unique to the Fungi?
Plasmogamy distant in time from karygamy
Zygomycota
Possess many septa in their hyphae cells
Glomeromycota
Are associated with 80%-90% of all plants
In most sac fungi, the ascospores are _____ and the hyphae are, _____. When the hyphae of two different mating types fuse, a _____ results
Haploid; haploid; dikaryon
Which statement about sexual reproduction in Basidiomycota is true?
The only diploid cells are those that contain fused nuclei
Sac fungus yeasts
Are often unicellular
The basidium of a club fungus is equivalent to the _____ of a sac fungus
Ascus
You are studying air pollution in New York City by documenting the abundance of lichens and the conditions likely to support them. What result are you likely to find?
Lichens are not abundant due to air pollution
Obelia is an example of a cnidarian that reproduces sexually _____
Sexually in its motile form and asexually in its sessile form
Which is a correct sequence in the life cycle of Obelia?
Zygote → planula → polyp → medusae
In which structure does meiosis occur?
Medusa
A biologist observes a single Obelia polyp on the sea floor not far from two large polyp colonies. What test could help determine whether the lone polyp arose from either or both large colonies as the result of asexual or sexual reproduction?
Compare sequences of several genes isolated from all three groups of polyps
What are the two main groups of protostomes?
Lophotrochozoans and ecdysozoans
Which feature distinguishes protostomes from deuterostomes?
Position of blastopore in embryo
Which feature is found in the common ancestor of the deuterostomes?
Pharyngeal slits
Which pieces of information support the idea that sea stars, acorn worms, and humans can be classified as deuterostomes?
Embryological data and genetic information
What explains why echinoderms have radial symmetry even though genetic analysis clearly places echinoderms with the deuterostomes that all share a bilaterally symmetrical common ancestor?
Echinoderms developed radial symmetry as a derived trait after splitting off from the common ancestor
A biologist discovers a new animal in a marine environment that has hexagonal radial symmetry. Of the following methods, which will best help him classify this organism with the deuterostomes or with some other group such as the ctenophores, sponges, or placozoans?
Raise the animal in the lab and trace the its embryological development
What does the term \”amphibian\” mean?
Double life
Which of the following statements about the frog life cycle is true?
The internal gills in the tadpole are replaced by lungs in the adult
In which stage of the frog’s life cycle does meiosis occur?
Adult
Protostome animals _____
Have a mouth derived from the blastopore
Which statement about the symmetry of organisms is true?
Radial symmetry is found in echinoderms
Which statement about coelomate animals is true?
They are triploblastic
Sponges
Reproduce both sexually and asexually
Which statement about ctenophores is true?
They have a complete gut
Which trait only occurs outside the lophotrochozoans?
Radial symmetry
Parasitic flukes of vertebrates can devote most of their bodies to reproduction because they _____
Acquire all of their nutrients from their host
Annelids
Have a coelom
Which statement about mollusks is true?
All mollusks have a shell
Ecysozoans
All have a cuticle
Arthropods are the most numerous animals on Earth. Which trait was least important to their success?
Molting
Which statement about crustaceans is true?
Most have a body that is composed of three regions
Which trait is unique to deuterostome animals?
Mouth formation on the end of embryos opposite the blastopore
Of the modern echinoderms _____
All have a water vascular system
Which statement about the notochord is true?
It is made up of large cells with turgid vacuoles
Which of the following best distinguishes amphibians and amniotes?
Egg structure
In the not-too-distant past, the theory that birds were reptiles was met with skepticism. What type(s) of evidence support this theory being true?
Molecular data
Marsupials differ from eutherians in that _____
Gestation in marsupials is brief
Place the following groups of eutherians in order of decreasing species richness.
(1) Bats
(2) Elephants
(3) Primates
(4) Rodents
(5) Shrews and moles
4; 1; 5; 3; 2
Homo neanderthalensis _____
Had a range that overlapped with that of Homo sapiens
Which of the following statements about air is correct?
As air falls, it contracts and becomes warmer
Precipitation tends to be _____ on the _____ side of a mountain because water vapor _____ as it rises there.
Higher; windward; condenses
The Cascade Mountains bisect the state of Washington into western and eastern portions. The western portion is bounded on its western border by the Pacific Ocean. The eastern portion is bounded on its eastern border by the state of Idaho. What might you predict about these two portions based on the information presented in the tutorial?
Eastern Washington has a higher proportion of drought-resistant vegetation than western Washington
Which of the following biomes has the greatest annual rainfall?
Tropical rain forest
Which of the following factors are important in determining the type of biome that characterizes a particular region?
Temperature and precipitation
Which of the following sets of biomes is placed in order from lowest to highest average annual temperature?
Tundra, woodland/shrubland, subtropical desert
Which of the following sets of biomes is placed in order from most to least biologically diverse?
Tropical rain forest, temperate seasonal forest, tundra
Which of the following aquatic biomes is known for its high biological diversity?
Coral reef
Which of the following sets of factors is important in distinguishing aquatic biomes?
Water temperature, water depth, water currents, salinity
Which of the following sequences places the aquatic biomes in order from lowest to highest salinity?
Stream, salt marsh, seagrass bed
Which of the following pairs of aquatic biomes shares the most similarities?
Salt marshes and mangrove forests
An ecological system encompasses _____
Biotic and abiotic factors
All of the field mice, grasshoppers, deer, hawks, and plants in a particular valley in Ohio constitute a _____
Community
The gut microbial community will be most similar between _____
Identical twins
Humans often experience digestive problems after taking a course of antibiotics to treat a bacterial infection, because the antibiotics destroy the body’s \”normal\” microbes. These microbes do all of the following except _____
Increased the flow of water out of the cells
How are climate and weather related to each other?
Climate is what is expected in a particular region, whereas weather is what actually occurs
The beaches with the strongest sunlight in December can be found in _____
Rio de Janeiro, Brazil
_____ energy drives global air circulation patterns
Solar
Global oceanic circulation is driven by all of the following except _____
Aquatic animals living in the oceans
Suppose that scientists discover a planet very similar to Earth. What information will be important in determining the growing seasons of the different regions on this new planet?
Temperature and precipitation
Rain tends to be much more common in mountains than in the adjacent lowlands because _____
Air cools as it travels up the mountains. Cool air holds less moisture than warm air, and the excess moisture is dropped as rain
Why does the leeward side of a mountain typically remain dry?
As air descends the slope, it warms and picks up moisture from the environment
Different types of tropical biomes are determined primarily by the _____ in that zone
Length of the dry season
The tundra biome is found _____
At high latitudes and in high mountains
In aquatic biomes you would not expect to find photosynthetic organisms in the _____ zone
Abyssal
A colleague brings you a sample containing an organism from an unknown location. It survives being subjected to dry conditions, continuous wave action, and full submersion in salt water but not in fresh water. This organism most likely comes from an _____
Intertidal Zone
The common periwinkle, Littorina littorea, is a small marine gastropod. Based on the name, it is most likely found in the _____ zone
Intertidal
Wallace’s line is based on what kind of barrier to dispersal?
A deep-water channel
Southern beeches, (genus Nothofagus), are found in South America, New Zealand, and Australia, as well as on certain islands of the southern Pacific Ocean. The most likely explanation for this widespread distribution is _____
Continental Drift
Which statement about the effect of human activities on ecological systems is true?
Human activities simplify natural ecosystems
When an ecologist designs a model to test a hypothesis about fires in a tropical savanna, knowledge about that ecosystem’s _____ is vital
Natural History
How do changing values for r affect the growth rate of a population?
Populations grow when r is positive, remain constant when r is zero, and shrink when r is negative
What is meant by the term \”doubling time\” and how did changing values for N0 affect the doubling time of a population?
Doubling time is the amount of time needed for a population to double in size; increasing N0 did not change the doubling time
The equations used in the tutorial apply to populations over short time intervals. Why can they not be applied to populations over very long time periods?
Real populations are affected by resource limitations that are not accounted for in the equations
How long will it take a population of 550 moose to double if 25 offspring are born and 14 moose die on average per year?
34.5 years
What is carrying capacity?
The number of individuals in a population that can be supported by an area
If the size of a population is greater than the carrying capacity (K), what will happen to the population?
The population will experience more deaths than births
According to the results of the simulation, how does distance affect the probability of extinction of subpopulations within a metapopulation, assuming that dispersal is active within the range of distances involved?
The greater the distance between subpopulations, the greater the probability of extinction
According to the results of the simulation, which subpopulations within a metapopulation are most likely to go extinct?
Small subpopulations separated by large distances with no dispersal
A biologist is studying a metapopulation of a turtle species. He counts the number of eggs laid by this species in each subpopulation within the metapopulation. The subpopulations range in size from very large to very small. The following are different possible outcomes of this study. Which outcome would suggest that the subpopulations are open systems rather than closed systems?
The number of eggs counted over many breeding seasons remained fairly constant across all subpopulations
For which population would density best be measured per unit of volume, instead of per unit of area?
Earthworms in the soil in Pennsylvania
You know that the population density of rabbits in an area is 80 individuals per square kilometer. The birth rate is 0.04 per week, and the death rate is 0.03 per week. From this information, population size would be calculated by _____
Multiplying the occupied area by 80
In a population of 400 deer, the per capita birth rate is 0.16 per year and the per capita death rate is 0.22 per year. In the following year, you would expect a(n) _____ of _____ deer in this population
Decrease; 24
There are 300 individuals in a population at time x. During the next month, 60 individuals are born and 30 die. What is the per capita growth rate per month?
0.1
If b, the per capita birth rate, is higher than d, the per capita death rate, which of the following is most likely to occur?
The population will grow because r > 0
The survivorship of five-year-old foxes is 0.34. The fecundity of these foxes is 0.54. What is the mortality of five-year old foxes?
0.66
You are experimenting with sunflower photosynthetic rates. You expose different plants to different light intensities, ranging from no light to full sun. What type of relationship would you expect to see between increasing light intensity and rate of photosynthesis?
The rate of photosynthesis would increase but eventually level off
The principle of _____ states that once an organism has acquired a unit of some resource, that bit of resource cannot be used for multiple functions at once
Allocation
Which population cannot survive indefinitely?
One with a per capita birth rate of 0.05 and a per capita death rate of 0.08
A hypothetical population not constrained by environmental limits would experience _____ growth
Multiplicative
The number of individuals of any particular species that can be supported by a particular environment is known as _____
The carrying capacity
An exponentially growing population of skunks has a doubling time of 10 years. In 2013 it had a population of 3,000. If it continues to grow at this rate, the population size will be _____ in the year 2033
12,000
At carrying capacity, r is _____
Zero
The current human population per capita growth rate is _____
Positive, but lower than i twas in 1963
The set of subpopulations in an area make up a _____
Metapopulation
The difference between the BD growth model and the BIDE model is the inclusion of _____ in the BIDE model
Immigration and emigration
By necessity, in the BD model (not the BIDE model), populations are considered to be _____
Closed systems
Fishermen prefer to catch _____ rockfish, and this has led to a(n) _____ in the size of rockfish
Larger: decrease
The most effective way to reduce the number of ticks that cause Lyme disease in an area would be to _____ the number of _____
Decrease; Small mammals
In Janzen’s experiment, which of the following conditions describes his control group?
Acacia trees that are left undisturbed
In Janzen’s experiment, which of the following actions was performed on the experimental group?
Acacia trees were fumigated to remove ants
Suppose that Janzen had found no difference in survival rates of acacia trees in his control and experimental groups. Which of the following conclusions would he have drawn?
A mutualistic relationship may exist because trees may benefit in some way (e.g., reproductive success) not revealed by this experiment
If two organisms use the same resources and those resources are insufficient to supply their combined needs, the organisms’ interactions constitute _____
Competition
Predation is the type of interaction in which _____
One participant is harmed while the other benefits
Mutualism is the type of interaction in which ____
Both participants benefit
Commensalism is the type of interaction in which _____
One participant benefits and the other is unaffected
Guppies (fish) swimming in a stream disrupt the growth of algae without any effect on the fish. This relationship can best be described as _____
Amensalism
If you set up an experiment pairing different species of Paramecium together, under what circumstance would one species be least likely to go extinct?
Mutualism
A population of plants has a per capita growth rate of -0.12 per year. The presence of a mutualistic aphid increases this rate by 0.002 per aphid per square meter. Keeping the per capita growth rate of the plant above zero requires a _____ density of aphids of _____ per m2
Minimal; 61
At low densities and in the absence of any other beetle species, the population of a strain of the flour beetle Tribolium castaneum grows at a per capita rate of 0.3 per week. In controlled lab conditions, the per capita growth rate is reduced by 0.015 for every 100 individuals. The addition of a related beetle, Tribolium freemani, further reduces the per capita growth rate of T. castaneum by 0.02 for every 100 T. freemani individuals. If there are 800 T. castaneum and 500 T. freemani individuals, what is the per capita growth rate of the T. castaneum population?
0.08
Which factor is most likely to promote the coexistence of competing species via rarity advantage?
Interspecific competition being weaker than intraspecific competition
In a mythical world, Kelters eat Fygons and Joosts. Joosts are autotrophs, while Fygons eat autotrophs. Based on this information you would conclude that Kelters are _____
Omnivores
Which statement about primary consumers is true?
They are herbivores
The Muir effect _____
Expresses the idea that different components of food webs are often interdependent
Species introduced to regions outside their original range that then spread widely and become abundant at a cost to the native species of the region are known as _____ species
Invasive
Defensive strategies are most likely to evolve in ______
The resource of a consumer-resource relationship
A plant species produces a chemical that is toxic to herbivores. Over time, herbivores that can detoxify the chemical increase in frequency. A mutation in the plant produces a new, different toxic chemical that the herbivores cannot detoxify. This is an example of _____
An evolutionary arms race
Which relationship is most likely to lead to resource partitioning?
Interspecific Competition
Trading of goods and/or services between individuals of different species _____
Is most likely to be found in mutualists
Which statement about mutualisms is false?
They are highly stable
At Glacier Bay, Alaska, the gravel deposits left behind by a retreating glacier were colonized first by which of the following organisms?
Microorganisms
At Glacier Bay, Alaska, why were Dryas (an herbaceous plant) and alder trees among the first plants to appear during the ecological succession of gravel deposits left behind by a retreating glacier?
Dryas and alder trees have nitrogen-fixing bacteria in nodules on their roots
After reading about the changes at Glacier Bay, a student remarks that the pattern and interactions of organisms present at each stage in succession creates the conditions that lead to the pattern present at the next stage. A second student remarks that the soil produced at each stage of succession helps define the pattern present at the next stage. Evaluate these two statements
Both statements are accurate
According to results from the simulation in the tutorial, which island characteristics are associated with the highest species richness?
Large and close to the mainland
Which statement is supported by the MacArthur-Wilson model simulation?
Species diversity depends on the rates of colonization and extinction, which depend on the size and location of an island
A tsunami strikes a large peninsula, destroying the bird populations living there. The tsunami also fragments the peninsula into three islands of similar size but different distances from the mainland. What would the MacArthur-Wilson model predict about bird populations on these islands in the future?
The rates of colonization of bird species will decrease with increasing distance of the island from the mainland, leading to lesser diversity with distance
As a forest becomes fragmented into smaller and smaller patches, the effects of fragmentation on these patches _____
Increase
The microclimate at the edge of a forest fragment differs from that inside the forest. Which of the following is generally true of the edges compared to the interior of the forest?
The edges have lower humidity
Ideally, what should a land use committee do as it maps out areas of undeveloped land to convert to human housing?
Maximize the ratio of land area to edge length of a single undeveloped land fragment that will remain after development
A group of species that coexist and interact with one another in a defined geographic area is a _____
Community
What is the difference between species composition of a community and community structure?
Community structure takes into account the abundance of different species in a community, while species composition does not
An ecologist measures off a transect running through a park and identifies plants at regular intervals. The transect passes through various types of soils. As she moves through the transect she observes that some plants thin out as new ones appear, but that this change is gradual. This pattern is called _____
Species turnover
Which process does not contribute to species composition changes over short periods of time?
Evolution
A researcher is comparing the heights of the tallest plants found in communities where pollinators are abundant to those in communities where pollinators are scarce. The researcher is testing whether there is a relationship between _____ and pollinators
Habitat Structure
In 2011, a tornado tore through Springfield, Massachusetts, destroying a large proportion of the trees in the area. This event is an example of _____, and the subsequent growth of new trees is an example of _____
Disturbance; succession
The GPP of a community is 40 units per day on average, while the NPP of the community is 15 units per day. How many units are used for cellular respiration and other catabolic processes of the plants?
25
GPP and NPP are most closely associated with _____
Community function
The NPP of a community is 150 units per month and the GPP is 240 units per month. If the ecological efficiency of herbivores is 1/6, how many units of plant biomass are converted into biomass of herbivores?
25
You are a scientist designing an experiment to investigate NPP over large expanses of Earth’s surface. Which of the following could be measured by satellite to correlate with NPP?
Sunlight absorption by chlorophyll
Productivity in a community _____ with increasing species number and _____ with an increase in the number of functional groups
Increases; decreases
Which community has the highest species diversity?
Community 3, with four equally abundant species
There are five species of beetles of roughly equal abundance in a community. A storm substantially reduces the population of one species. This would result in a decrease in species _____ and no change in species _____
Diversity; richness
Species richness is highest in the _____
Tropics
Islands that are _____ and _____ the mainland tend to have the most species
Large; near
The mammalian fauna of an island is behaving in accordance with the MacArthur and Wilson theory of island biogeography. If the food supply on the island is permanently reduced, you would expect the number of mammalian species to _____, because _____ will _____
Decrease; extinction; increase
An island is at equilibrium in terms of species richness when the _____
Immigration rate is equal to the extinction rate
Earthworm activity adds nutrients and oxygen to the soil and makes it more homogenous. Thus, this soil has more value for agriculture. Which term best describes the agricultural value of earthworms?
Ecosystem service
Based on the theory of island biogeography, fragmentation should have the least effect when _____
Patches are close to one another
Wolves are crucial for maintaining healthy aspen forests because of their effects on _____
Trophic cascades
Which of the following is the major compartment for carbon in Earth’s system?
Fossil fuels
How are humans influencing the carbon cycle?
By cutting forests and burning biomass, which increase the atmospheric pool of CO2; Through changes in land use, which increase the atmospheric pools of CO2 and CH4; By burning fossil fuels and manufacturing cement, which increase the atmospheric pool of CO2
By what process does nitrogen enter the living components of ecosystems?
Through fixation by microbes
How are humans influencing the nitrogen cycle?
By increasing the rate of nitrogen fixation through industrial processes and intensive agriculture; By increasing the production of oxides of nitrogen and other chemical forms through livestock production and some forms of agriculture; By increasing the production of oxides of nitrogen and other chemical forms through burning fossil fuels and biomass
Which pathway represents the shortest path that a nitrogen atom in atmospheric nitrogen, N2, could travel and end up in a protein in a human?
N2 → bacterium → plant → human
A student remarks that it is a good thing that humans discovered how to use industrial processes to fix nitrogen because this ensures that the nitrogen cycle can remain intact if nitrogen-fixing bacteria ever go extinct. Evaluate the accuracy of this statement.
The statement is inaccurate because humans would not be able to distribute the product of nitrogen fixation from industrial processes in the same way that bacteria are able to distribute it globally now

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