Bio concepts #3 Flashcards
(219 cards)
1
Q
Charles Darwin is best known for this book
A
On the Origin of Species by Means of Natural Selection
2
Q
Anaximander argued humans are the offspring of what animal?
A
fish
3
Q
Jean-Baptiste Lamarck is most notably associated with what theory?
A
Transmutation theory
4
Q
Characteristics acquired by habits and other behavioral adaptations to changes in the environment could be genetically transmitted to offspring
A
Transmutation theory
5
Q
The imprints or remains of organisms that lived in the past
A
fossils
6
Q
document differences between past and present organisms
A
fossils
7
Q
Reveal that many species have become extinct
A
fossils
8
Q
Reveals the historical sequence in which organisms have evolved
A
fossil record
9
Q
Link early extinct species with species living today
A
fossils
10
Q
What does “descent with modification” mean in Darwin’s theory?
A
all life is connected by common ancestry, and descendants accumulate adaptations to changing environments over time.
11
Q
How did Darwin’s theory differ from the long-held view of the Earth and species?
A
Darwin’s theory suggested that the Earth is very old and that species change over time through evolution, whereas the long-held belief was that the Earth was young and species were unchanging.
12
Q
Why is Darwin’s concept of evolution by natural selection considered a theory?
A
it is broader in scope than a hypothesis, generates new hypotheses, and is supported by a large body of evidence.
13
Q
What discovery in the late 1970s supported the idea that whales evolved from land-dwelling mammals?
A
Paleontologists unearthed transitional fossils and concluded that whales likely arose from a wolf-like carnivore.
14
Q
What did molecular biologists discover about the relationship between whales and hippopotamuses?
A
Molecular biologists found a close genetic relationship between whales and hippopotamuses and hypothesized that both are descendants of a common cloven-hoofed ancestor.
15
Q
What did the discovery of Pakicetus and Rodhocetus in 2001 reveal about whale evolution?
A
The fossils of Pakicetus and Rodhocetus showed the distinctive ankle bone of a cloven-hoofed mammal, confirming that whales are closely related to land-dwelling, cloven-hoofed ancestors.
16
Q
A process of descent with modification
A
evolution
17
Q
Evolution is described as what type of process?
A
remodeling process
18
Q
Similarity resulting from common ancestry is known as what?
A
homology
19
Q
reveal evolutionary relationships
A
structural and molecular homologies
20
Q
remnants of features that served important functions in the organism’s ancestors
A
vestigial structures
21
Q
Helps explain why early stages of development in different animal species reveal similarities not visible in adult organisms
A
understanding of homology
22
Q
How do biologists represent patterns of descent?
A
Biologists use an evolutionary tree (often turned sideways) to show patterns of descent, illustrating how species are related through common ancestry.
23
Q
What types of homologies can be used to determine the branching sequence of an evolutionary tree?
A
Both anatomical structures (e.g., bones, organs) and molecular structures (e.g., DNA, proteins) can be used to determine the branching sequence of an evolutionary tree.
24
Q
Darwin’s greatest contribution to biology
A
explanation of how life evolves
25
How did Darwin use artificial selection to support his theory of natural selection?
Darwin reasoned that if artificial selection could produce significant changes in a short time, then natural selection could cause even greater modifications in species over hundreds or thousands of generations.
26
What does it mean that individuals do not evolve, but populations do?
Natural selection acts on individual organisms, but evolution occurs at the population level over time, as the frequency of traits changes across generations.
27
What types of traits can natural selection act on?
Natural selection can only amplify or diminish traits that are heritable—traits that can be passed on to offspring through genetic inheritance.
28
Is evolution goal-directed?
No, evolution is not goal-directed. It does not lead to perfectly adapted organisms
29
What is an example of natural selection in action related to pesticides?
insects with genetic mutations that provide resistance survive and reproduce, leading to more resistant populations over time.
30
Why is natural selection considered more of an editing process than a creative mechanism?
Natural selection edits the gene pool by favoring traits that already exist in a population, rather than creating new traits or perfect organisms. It acts on genetic variation that is already present.
31
How is natural selection contingent on time and place?
Natural selection favors traits that are advantageous in a specific environment at a specific time, meaning the traits that are beneficial can vary depending on environmental conditions.
32
typically show individual variation
organisms
33
the ultimate source of the genetic variation that serves as raw material for evolution
mutations
34
How is most genetic variation in sexually reproducing organisms generated?
Most genetic variation results from the unique combination of alleles that each individual inherits, due to processes like independent assortment, recombination, and random fertilization during sexual reproduction.
35
What are the three random components of sexual reproduction that generate fresh assortments of alleles every generation?
crossing over, independent orientation of homologous chromosomes during meiosis, and random fertilization.
36
What is crossing over, and how does it contribute to genetic variation?
the exchange of genetic material between homologous chromosomes during meiosis, leading to new combinations of alleles.
37
How does the independent orientation of homologous chromosomes at metaphase I of meiosis contribute to genetic variation?
During meiosis, the homologous chromosomes align independently at metaphase I, resulting in a random distribution of maternal and paternal chromosomes to the gametes, increasing genetic diversity.
38
How does random fertilization contribute to genetic variation?
any sperm can fertilize any egg, leading to numerous possible combinations of alleles in the offspring.
39
a group of individuals of the same species that live in the same area and interbreed
population
40
consists of all copies of every type of allele, at every locus, in all members of the population.
gene pool
41
a change in the frequencies of alleles in a population’s gene pool and evolution occurring on its smallest scale.
microevolution
42
What are the conditions under which allele and genotype frequencies will remain constant, according to the Hardy-Weinberg equilibrium?
A large population, Random mating, No mutation, no gene flow, or no natural selection.
43
How does a large population contribute to Hardy-Weinberg equilibrium?
A large population helps prevent random changes in allele frequencies due to genetic drift, maintaining allele frequencies over generations.
44
Why is random mating important for Hardy-Weinberg equilibrium?
Random mating ensures that alleles combine in a way that does not favor any particular genotype, allowing allele frequencies to remain unchanged.
45
How do mutation, gene flow, and natural selection affect Hardy-Weinberg equilibrium?
These factors disrupt equilibrium by introducing new alleles, changing allele frequencies, or favoring certain genotypes, which causes evolution to occur.
46
How can the Hardy-Weinberg equation be used to test whether evolution is occurring?
The Hardy-Weinberg equation predicts expected allele and genotype frequencies. If observed frequencies differ from the expected ones, it suggests that evolutionary forces are acting on the population.
47
What does it mean if a population's allele frequencies match those predicted by the Hardy-Weinberg equation?
If the population’s allele frequencies match the predictions, it indicates that no evolution is occurring, and the population is in Hardy-Weinberg equilibrium.
48
What happens if a population’s allele frequencies do not match those predicted by the Hardy-Weinberg equation?
If allele frequencies deviate from the predictions, it suggests that evolutionary processes (e.g., natural selection, mutation, or genetic drift) are influencing the population, causing evolution to occur.
49
What are the three main causes of evolutionary change?
natural selection, genetic drift, and gene flow
50
How does natural selection contribute to evolutionary change?
Natural selection favors individuals with traits that enhance survival and reproduction, causing those traits to become more common in the population over time.
51
What is genetic drift, and how does it cause evolutionary change?
Genetic drift is a random change in allele frequencies due to chance events, and it is more significant in small populations.
52
How does gene flow lead to evolutionary change?
Gene flow occurs when individuals migrate between populations, introducing new alleles and increasing genetic diversity within a population.
53
What is the bottleneck effect, and how does it impact genetic diversity?
The bottleneck effect occurs when a population is drastically reduced in size (due to a catastrophe or other event), leading to a loss of genetic diversity because only a small subset of the original gene pool survives.
54
How does the founder effect lead to genetic drift?
The founder effect occurs when a small group of individuals colonizes a new habitat or island, carrying only a subset of the original population's genetic variation, leading to reduced genetic diversity in the new population.
55
How do the bottleneck effect and founder effect contribute to genetic drift?
Both effects cause genetic drift by reducing the population size and limiting genetic variation. In the bottleneck effect, this happens due to a population collapse, while in the founder effect, it occurs when a small group establishes a new population.
56
What is relative fitness?
the contribution an individual makes to the gene pool of the next generation, compared to the contributions of other individuals in the population.
57
How is relative fitness determined?
by how many offspring an individual produces and how many of those offspring survive and reproduce, relative to other individuals in the population.
58
What is stabilizing selection, and how does it affect a population?
Stabilizing selection favors intermediate phenotypes, selecting against extreme traits. This reduces variation and maintains the status quo in the population.
59
What is directional selection, and how does it affect a population?
Directional selection shifts the overall makeup of the population by favoring one of the phenotypic extremes over the other, leading to a gradual change in the population's characteristics.
60
What is disruptive selection, and when does it occur?
Disruptive selection favors extreme traits over intermediate traits. It typically occurs when environmental conditions vary, making extreme traits more advantageous than intermediate ones.
61
a form of natural selection in which individuals with certain characteristics are more likely than other individuals to obtain mates
sexual selection
62
How can secondary sex characteristics give individuals an advantage in mating?
Secondary sex characteristics, such as bright colors, large size, or elaborate displays, can help individuals attract mates, increasing their chances of reproducing and passing on those traits.
63
What is intrasexual selection, and how does it influence mating?
Intrasexual selection occurs when individuals of the same sex compete directly for mates, such as through physical contests or displays, leading to increased reproductive success for the winner.
64
Why is evolution constrained by existing variation?
Evolution can only act on the genetic variation already present in a population. New, advantageous alleles do not arise on demand, and natural selection works with what exists.
65
How does historical constraints limit evolution?
Evolution co-opts existing structures and adapts them to new situations. Organisms are limited by their evolutionary history and cannot create entirely new, unrelated structures from scratch.
66
Why are adaptations often compromises?
Adaptations often serve multiple functions, and optimizing one function may limit the ability to perform others. This makes evolution a process of balancing different needs rather than achieving perfection.
67
How do chance, natural selection, and the environment interact in evolution?
Evolution is shaped by random events (like genetic drift), natural selection, and environmental factors. Because environments change unpredictably, evolution is a dynamic process that can take unexpected paths.
68
the process by which one species splits into two or more species, accounts for both the unity and diversity of life
speciation
69
What does the biological species concept define a species as?
A species is a group of populations whose members can interbreed in nature and produce fertile offspring, but not with members of other species. This concept emphasizes reproductive isolation.
70
What is reproductive isolation in the context of the biological species concept?
Reproductive isolation occurs when members of different species are prevented from interbreeding, either by physical barriers or biological differences, maintaining species boundaries.
71
What are some limitations of the biological species concept?
The BSC is problematic for: Asexual organisms, Hybridization (when species can interbreed and produce fertile offspring), Fossil species (can't test interbreeding), Ring species (connected populations with limited or no interbreeding)
72
based on observable physical traits and can be applied to asexual organisms and fossils
morphological species concept
73
defines a species by its ecological niche and focuses on unique adaptations to particular roles in a biological communtiy
ecological species concept
74
defines a species as the smallest group of individuals that share a common ancestor and thus form one branch of the tree of life
phylogenetic species concept
75
serve to isolate the gene pools of species and prevent inbreeding
reproductive barriers
76
What is the difference between prezygotic and postzygotic reproductive barriers?
Prezygotic barriers prevent fertilization from occurring, while postzygotic barriers affect the viability or fertility of offspring after fertilization.
77
What are some examples of prezygotic barriers?
Habitat isolation, Temporal isolation, Behavioral isolation, Mechanical isolation, Gametic isolation
78
What are some examples of postzygotic barriers?
Hybrid inviability, Hybrid sterility, Hybrid breakdown
79
How can a geographically separated small population become genetically unique?
A small, geographically separated population can become genetically unique due to natural selection, mutation, and genetic drift, which alter its gene pool over time.
80
How does natural selection contribute to genetic uniqueness in a separated population?
Natural selection acts on traits that are advantageous in the new environment, leading to changes in allele frequencies that may differ from the original population.
81
How does mutation contribute to genetic uniqueness in a separated population?
Mutation introduces new genetic variations in the small population, adding to the differences between the isolated population and the original one.
82
How does genetic drift affect genetic uniqueness in a separated population?
Genetic drift causes random changes in allele frequencies in small populations, which can lead to significant genetic differences over time.
83
How can different food sources contribute to the development of reproductive barriers?
When populations of a species adapt to different food sources, they may evolve differently in terms of mating preferences and behavior, leading to ecological isolation and reproductive barriers over time.
84
How do different pollinators lead to reproductive isolation?
Populations of plants can adapt to different pollinators (e.g., bees vs. hummingbirds), leading to behavioral isolation where populations no longer interbreed due to differences in pollination and mating behaviors.
85
How does flower color influence reproductive isolation in monkey flowers?
In monkey flowers, a gene for flower color affects pollinator choice, leading to reproductive isolation between species by attracting different pollinators, which prevents interbreeding.
86
How do predators or environmental pressures contribute to reproductive barriers?
Differences in environmental pressures like predators or habitat conditions can lead to geographical isolation and changes in mating behaviors, further promoting reproductive isolation.
87
occurs when a new species arises within the same geographic area as its parent species
sympatric speciation
88
duplication of the chromosome number due to errors in cell division
polyploidy
89
How can habitat differentiation contribute to sympatric and allopatric speciation?
Habitat differentiation can lead to speciation by causing populations to exploit different resources or habitats. This reduces interbreeding, which can eventually lead to sympatric speciation or allopatric speciation
90
How does sexual selection drive speciation?
Sexual selection, through mate choice, can cause populations to evolve distinct traits. Over time, this can lead to sympatric speciation when mating preferences cause reproductive isolation within the same geographic area.
91
What is the difference between sympatric and allopatric speciation?
Sympatric speciation occurs when new species form within the same geographic area, often due to habitat differentiation or sexual selection. Allopatric speciation occurs when a population is geographically isolated, leading to genetic divergence over time.
92
How does sexual selection contribute to sympatric speciation?
Sexual selection can lead to sympatric speciation if different populations within the same area develop distinct mating preferences, causing reproductive isolation and eventually leading to the formation of new species.
93
How does experimental evolution help biologists test speciation?
By observing the process of speciation in laboratory populations (e.g., fruit flies or bacteria), scientists can manipulate variables and track how isolation, genetic drift, and natural selection drive species formation.
94
Why are isolated ecosystems (like islands) useful for studying speciation?
Isolated ecosystems provide natural laboratories where populations can become genetically isolated, allowing scientists to study how genetic drift, natural selection, and sexual selection lead to the formation of new species.
95
How has sexual selection contributed to the diversification of cichlids in Lake Victoria?
driven diversification by favoring traits like coloration and behavior that are selected by females. These preferences have led to speciation through mate choice and sexual dimorphism.
96
What role does coloration play in the speciation of cichlids in Lake Victoria?
in mate choice, with females selecting brightly colored males. This has led to the evolution of different color morphs and contributed to reproductive isolation and speciation.
97
What is adaptive radiation, and how does it apply to cichlids in Lake Victoria?
Adaptive radiation refers to the rapid diversification of species from a common ancestor. In Lake Victoria, sexual selection and ecological factors have led to the emergence of hundreds of cichlid species in a relatively short time.
98
How does behavioral isolation contribute to speciation in cichlids?
Behavioral isolation, such as distinct mating rituals or courtship behaviors, prevents interbreeding between cichlid species, further promoting reproductive isolation and speciation.
99
How is sexual selection a form of sympatric speciation in Lake Victoria?
In Lake Victoria, sexual selection based on traits like coloration and behavior has led to sympatric speciation, where new cichlid species form within the same geographic area due to reproductive isolation.
100
the evolution of many diverse species from a common ancestor is known as
adaptive radiation
101
How does isolation lead to speciation on islands?
reduces gene flow between populations, allowing for genetic divergence and the evolution of distinct species due to different environmental pressures and conditions.
102
What is adaptive radiation, and why does it occur on islands?
the rapid diversification of an ancestral species into many species, each adapted to different ecological niches. It occurs on islands due to the availability of various habitats and limited competition.
103
How does recolonization contribute to speciation on islands?
Recolonization occurs when populations spread to different parts of an island or chain, leading to further isolation and speciation as populations adapt to different conditions, reinforcing reproductive isolation.
104
What is endemism, and why is it common on islands?
refers to species that are found only in a specific geographic location, such as an island. It is common on islands because species evolve independently in isolated environments, becoming specialized to local conditions.
105
Can you give examples of adaptive radiation on islands?
Darwin’s finches in the Galápagos, Hawaiian honeycreepers, and cichlids in the African Great Lakes, all of which evolved into multiple species adapted to different ecological niches.
106
Why are islands considered "natural laboratories" for studying evolution?
because they often provide geographic isolation, distinct ecological niches, and opportunities for adaptive radiation, allowing scientists to study speciation and the formation of endemic species.
107
How have morphological studies contributed to understanding the speciation of Darwin’s finches?
show how traits like beak size and shape evolved to suit different food sources, helping to define distinct species and reinforcing adaptive radiation and speciation in Darwin’s finches.
108
What role does geographic isolation play in the speciation of Darwin’s finches?
Geographic isolation between islands in the Galápagos Archipelago reduces gene flow between populations, leading to genetic divergence and the evolution of new species, as seen in Darwin’s finches.
109
How have genetic studies advanced our understanding of Darwin’s finches speciation?
Genetic studies have confirmed that Darwin’s finches share a common ancestor and revealed how gene flow and selective pressures have driven their genetic divergence, leading to the formation of distinct species.
110
How does beak morphology correlate with the ecological roles of Darwin’s finches?
Beak morphology in Darwin’s finches is adapted to their food sources; large beaks for tough seeds, small beaks for insects, and specialized shapes for cactus flowers, driving their diversification into different species.
111
How have environmental changes influenced the speciation of Darwin’s finches?
Environmental changes like climate shifts and food availability (e.g., during droughts) have created selective pressures that favor certain traits in Darwin’s finches, driving speciation through adaptive radiation.
112
What did Peter and Rosemary Grant study in their long-term research on Darwin’s finches?
The Grants studied how natural selection influences beak size in Galápagos finches, specifically how environmental factors (like food availability) drive evolutionary changes in real time.
113
How did the 1977 drought impact beak size in Darwin’s finches?
led to a scarcity of small seeds, favoring finches with larger beaks that could crack harder seeds, resulting in an increase in average beak size in the population due to natural selection.
114
What did the Grants’ studies reveal about the genetic basis of beak size in Darwin’s finches?
The Grants discovered that beak size was heritable, meaning that offspring tended to inherit the beak size of their parents, allowing natural selection to act on this trait over generations.
115
How do environmental changes like drought and rainfall affect evolutionary processes in Darwin’s finches?
Environmental changes such as drought and rainfall influence the abundance of different seed types, favoring finches with either larger or smaller beaks depending on the food availability, leading to fluctuations in beak size over time.
116
Why are the Grants’ studies on Darwin’s finches considered a landmark in evolutionary ecology?
The Grants’ research is groundbreaking because they observed evolution in real time, documenting how natural selection acts on beak size and other traits in response to immediate environmental pressures.
117
How quickly did the Grants observe evolutionary changes in beak size in their finch population?
The Grants observed evolutionary changes in beak size over just a few generations, showing how natural selection can cause rapid evolutionary shifts in response to environmental changes like drought and food availability.
118
What is a hybrid zone?
a region where two closely related species come into contact and mate, producing at least some hybrid offspring.
119
What is reinforcement in the context of hybrid zones?
Reinforcement occurs when natural selection strengthens reproductive barriers between two species, preventing hybridization and promoting speciation.
120
What does fusion mean in the context of hybrid zones?
Fusion is the process by which two species that once diverged and formed a hybrid zone merge back into a single species due to increased gene flow and similar fitness of hybrids.
121
How does a stable hybrid zone differ from other outcomes of hybridization?
In a stable hybrid zone, hybrids continue to be produced, but the two species maintain their genetic distinction and do not merge or evolve into separate species over time.
122
What factors determine whether a hybrid zone will result in reinforcement, fusion, or remain stable?
the fitness of hybrids, the degree of reproductive isolation between the species, environmental conditions, and the genetic compatibility of the parent populations.
123
How does hybrid fitness influence the outcome of hybridization in contact zones?
If hybrids are fit and can reproduce successfully, fusion between species is more likely. If hybrids have low fitness, reinforcement may occur to maintain species separation.
124
What is the key difference between artificial selection and natural selection in terms of the number of generations?
Artificial selection occurs over a relatively short number of generations, while natural selection typically requires a much greater number of generations to result in significant changes.
125
Why must some members of a population be genetically resistant to a pesticide for resistance to develop?
Some individuals must be genetically resistant so they survive the pesticide and pass on their resistance traits to future generations.
126
What characteristic of Ambulocetus helped it function well on land and in water?
Joints of forelimbs (land): allowed movement on land; Powerful tail and large, paddle-like hind feet (water): aided in swimming.
127
What effect did farming and human activities in the 19th and 20th centuries have on the greater prairie chicken population?
These populations experienced the bottleneck effect, which reduced their number of alleles.
128
What did Peter and Rosemary Grant's research on beak size in finches in the Galápagos Islands show?
that natural selection is an ongoing, constant process
129
Which outcome from experiments with birds and frogs supports the hypothesis that females prefer male traits linked to "good genes"?
The offspring of more attractive males have better health and longer survival than the offspring of less attractive males.
130
What do the similarities in DNA, RNA, and genetic code among all living things provide strong evidence for?
They provide strong evidence for descent from a very distant common ancestor.
131
For most plants and animals, what is the mutation rate per generation, and in which type of populations will this rate have the least impact?
The mutation rate is about 1/100,000 genes per generation, and it has the least impact in populations with long time spans between generations.
132
What results from an inactive pseudogene that normally encodes for the enzyme GLO?
Humans must consume vitamin C in their diet.
133
What is the age range of fossils observed in the sedimentary rock at the Grand Canyon?
The fossils are hundreds of millions of years old.
134
What mechanism of microevolution is revealed by rats from one town in Norway hitching rides on different ships, resulting in different fur colors on each ship after ten years?
the effects of the founder effect.
135
What causes new alleles to arise, and what does this result in?
by mutation, which causes genetic variation.
136
What are the characteristics of a scientific theory?
A scientific theory is a widely accepted explanatory idea, broader than a hypothesis, that generates new hypotheses and is supported by a large body of evidence.
137
What is a typical use of the Hardy-Weinberg equation in public health?
It is used to estimate the number of people with alleles for specific diseases.
138
What are the consequences for a population of balancing selection and heterozygote advantage?
They preserve genetic variation.
139
Why can't natural selection fashion "perfect" organisms?
because adaptations are often compromises, evolution is limited by historical constraints, and change, natural selection, and the environment all interact.
140
What type of selection was operating in Maine when two extremely cold winters led to increased survival of barn swallows with larger bodies?
Directional selection.
141
What is the definition of a fossil cast?
A fossil cast is an empty mold of a specimen left in sediment that is filled in with dissolved minerals.
142
In evolutionary terms, how is an organism's relative fitness measured?
An organism's relative fitness is measured by its contribution to the gene pool of the next generation relative to the contribution of other organisms to that gene pool.
143
Among antibiotic-resistant bacteria, which causes the highest number of infections, and which causes the greatest proportion of "urgent" cases according to the CDC?
Streptococcus pneumoniae causes the highest number of infections, while Neisseria gonorrhoeae causes the greatest proportion of cases classified as "urgent" by the CDC.
144
Which conditions favor the development of drug resistance in bacteria?
Random mutation and nonrandom selection.
145
What is one consequence of increased human mobility compared to 300 years ago?
Gene flow is a more important cause of microevolution than in the past.
146
What is the first step in allopatric speciation of a population?
Geographic isolation of subpopulations.
147
What does the different mating calls of three frog species living in the same pond illustrate?
This illustrates behavioral reproductive isolation, which is a prezygotic barrier to reproduction.
148
Which species concept has been used to identify the largest number of species and is particularly useful for studying speciation in fossils?
morphological
149
What might occur over time in a squirrel population after an earthquake causes a large stream to flow down the center of the valley?
Two allopatric species of squirrel would evolve.
150
What is it called when one common ancestor gives rise to many diverse species?
Adaptive radiation.
151
What is the term for fossils in different layers of rock showing slight differences, with many transitional fossils linking newer species to older ones?
Gradual equilibrium.
152
What is the term for fossils that appear suddenly in strata of rock, persist through several layers, then disappear just as suddenly?
Punctuated equilibrium.
153
What would you predict will occur as the water of Lake Victoria becomes murkier due to pollution and development, affecting the cichlid fish species?
An increasing proportion of hybrids will form.
154
What did the work of Peter and Rosemary Grant in the Galápagos Islands show?
evolution of finch beak sizes over a 40-year period.
155
What does the difference in appearance between collared and pied flycatchers in allopatric versus sympatric habitats illustrate?
reinforcement of a reproductive barrier.
156
What is one limitation of the biological species concept?
Its inability to differentiate species of prokaryotes.
157
What is likely to occur in a hybrid zone?
Members of different species have opportunities to meet and mate.
158
What should the farmer write to the rice sellers after discovering that the plants from two different companies produced weak offspring that did not produce seeds?
"The rice plants you sent me showed hybrid breakdown. Please refund my money."
159
How is sympatric speciation best defined?
Sympatric speciation is speciation that occurs without geographic separation between populations.
160
What is the chromosome count in the gametes of a tetraploid plant (4n) compared to its parent diploid plant, and with which plants can a tetraploid plant successfully mate?
The gametes of a tetraploid plant (4n) contain 2n chromosomes, while the gametes of its parent diploid plant contain n chromosomes. A tetraploid plant can successfully mate with itself or another tetraploid.
161
What would you predict would occur over time if starch- and maltose-preferring fruitflies were allowed to breed only with others of the same food preference?
The populations would become more reproductively isolated from one another.
162
The evolution of numerous species, such as Darwin’s finches, on different, isolated islands in the Galápagos is an example of __________.
Adaptive radiation
163
Females of different species of firefly respond to different blinking rhythms by the males of their own species. This is an example of a __________ reproductive barrier.
behavioral
164
Most hybrid animals are sterile. This illustrates a type of __________.
Postzygotic reproductive barrier.
165
Grolar bears result from __________ contact between __________ because of __________.
Increased: polar bears and grizzly bears: melting ice.
166
One species of male bowerbirds builds elaborate bowers filled with colorful objects, while another species builds simpler bowers filled with drab-colored objects. This example could be used to demonstrate which of the following?
The importance of sexual selection by females in speciation.
167
Which species concept is described by the statement: "Members of the same species occupy the same niche"?
Ecological species concept.
168
Which species concept is described by the statement: "Members of the same species have the potential to interbreed in nature and produce fertile offspring"?
Biological species concept.
169
Which species concept is described by the statement: "Members of the same species share a common ancestor"?
Phylogenetic species concept.
170
What observations did scientists make that led them to conclude that pollinator preference preserves the reproductive barrier between two species of monkeyflowers?
Bees visit only pink-colored monkey flowers; hummingbirds visit only red-colored monkey flowers.
171
Why do we usually recover completely from a cold, but rarely recover completely from polio?
The cells of the respiratory tract undergo mitosis, whereas mature nerve cells do not divide.
172
How is a protein made from DNA?
DNA is transcribed into RNA, and RNA is translated into a polypeptide (protein).
173
What is transcription?
Transcription is the synthesis of RNA under the direction of DNA.
174
What is translation?
Translation is the synthesis of proteins under the direction of RNA.
175
How is a gene currently defined?
A gene is a region of DNA that can be expressed to produce a functional product, either a polypeptide or an RNA molecule.
176
What does the sequence of nucleotides in DNA provide?
The sequence of nucleotides in DNA provides a code for constructing a protein.
177
What does translation require in terms of language conversion?
Translation requires the conversion of the nucleic acid language (RNA) to the polypeptide language (protein).
178
What happens during translation in terms of language change?
During translation, there is a change from the nucleotide sequence of the RNA to the amino acid sequence of the polypeptide.
179
What is the triplet code in gene expression?
The triplet code is the genetic instruction for the amino acid sequence of a polypeptide, written in DNA and RNA as nonoverlapping three-base "words" called codons.
180
What is the genetic code?
The genetic code is the set of rules that dictates the amino acid translation of each mRNA nucleotide triplet.
181
How do nearly all organisms use the genetic code?
Nearly all organisms use an identical genetic code to convert mRNA codons transcribed from a gene into the amino acid sequence of a polypeptide.
182
What happens during transcription in the nucleus?
In the nucleus, the DNA helix unzips, RNA nucleotides line up, and RNA polymerase joins them along one strand of the DNA, following the base-pairing rules.
183
What is the role of a promoter in transcription?
A promoter is a specific nucleotide sequence that acts as a binding site for RNA polymerase and determines where transcription starts.
184
What happens when RNA polymerase reaches the terminator?
RNA polymerase adds RNA nucleotides until it reaches a sequence of DNA bases called the terminator, which signals the end of the gene.
185
What is the role of messenger RNA (mRNA)?
Messenger RNA (mRNA) encodes amino acid sequences and conveys genetic messages from DNA to the translation machinery of the cell.
186
What happens to eukaryotic transcripts before leaving the nucleus as mRNA?
Before leaving the nucleus as mRNA, eukaryotic transcripts undergo RNA splicing, where: Introns (noncoding segments) are spliced out, Exons (expressed parts) are spliced together, a cap and tail are added to the ends of the mRNA.
187
Where does translation take place?
Translation takes place in the cytoplasm.
188
How does a ribosome translate mRNA into a polypeptide?
A ribosome attaches to the mRNA and translates its message into a specific polypeptide, aided by transfer RNA (tRNA) molecules.
189
What is the structure of a tRNA molecule?
Each tRNA is a folded molecule with a base triplet called an anticodon on one end and a specific amino acid attachment site on the other end.
190
What are ribosomes and what is their function?
Ribosomes are structures in the cytoplasm that coordinate the functioning of mRNA and tRNA and catalyze the synthesis of polypeptides.
191
What are ribosomes made of?
Ribosomes are made of ribosomal RNA (rRNA) and proteins.
192
What do ribosomes have binding sites for?
Ribosomes have binding sites for tRNAs and mRNA.
193
What are the three phases of translation?
The three phases of translation are: Initiation, Elongation, Termination
194
What is brought together during the initiation phase of translation?
During initiation, mRNA, a tRNA bearing the first amino acid, and the two subunits of a ribosome are brought together.
195
How does the sequence of codons in DNA determine the structure of a polypeptide?
The sequence of codons in DNA, through the sequence of codons in mRNA, spells out the primary structure of a polypeptide.
196
What are mutations and what causes them?
Mutations are changes in the genetic information of a cell or virus, caused by errors in DNA replication or recombination, or by physical or chemical agents called mutagens.
197
How do nucleotide substitutions, insertions, or deletions affect a gene?
Substituting, inserting, or deleting nucleotides alters a gene, with varying effects on its function.
198
What term refers to large-scale changes in the history of life, such as the development of legs, the impact of mass extinctions, and the appearance of novel traits?
Macroevolution
199
All animals with eyes have
light-sensitive cells
200
Mammalian species expanded and diversified due to __________, during a period that followed __________.
Adaptive radiation: the Cretaceous extinction
201
Continental drift is caused by movements in Earth’s __________. It is a process that __________.
Mantle: is ongoing and causes Earth’s plates to move toward and away from one another
202
Miller and Urey’s groundbreaking experiments showed that __________.
organic molecules could have been generated from inorganic precursors
203
A tremendous increase in the diversity of life forms took place during the __________, which began about __________ years ago.
Cambrian explosion: 535 million
204
What are stromatolites?
Fossilized rocks made of layers of sediment built up by photosynthetic prokaryotes about 3.5 billion years ago.
205
What appeared between 2.7 and 1.2 billion years ago?
Photosynthetic prokaryotes, Multicellular organisms, Oxygen in the atmosphere
206
In the “RNA world,” what catalyzed the replication of RNA nucleotides?
(Ribozymes are RNA molecules that can catalyze reactions, including RNA replication.)
207
What is the cause of an earthquake due to a strike-slip fault?
Opposing crustal plates stick together, then suddenly jerk forward
208
What is the most likely cause of the Cretaceous mass extinction?
A large asteroid crashing to Earth, sending up a huge cloud of hot vapor and debris.
209
What are consequences of continental drift?
Formation of Pangea and Breakup of Pangea
210
Which taxonomic category contains all the others?
Phylum
211
Divergence of snakes and tetrapods from their common ancestor was largely due to the influence of __________.
Homeotic genes
212
What is thought to have been the first step in the origin of life?
Abiotic synthesis of organic molecules
213
What was a limitation of mid-20th century experiments on the origin of life?
Many organic molecules could not be identified.
214
“Molecular clock” data allowed researchers to estimate when
humans began wearing clothes
215
When a volcano erupts, material from Earth’s __________ is thrown into the air.
Mantle
216
What is the most likely way that volcanoes contributed to the Permian mass extinction?
Caused a global temperature increase of about 6° Centigrade
217
How is radiometric dating of fossils performed?
The relative concentrations of the radioactive and stable isotopes of an element are compared.
218
Scientists working in the field "evo-devo" have discovered which fact about spined stickleback fish?
Sticklebacks from the ocean and from lakes have the same gene for spines, but it is not turned on in the pelvic region of adult lake sticklebacks.
219
