Free Biology Flashcards about Bio101 Chpt 13

Question Answer
What broad set of ideas was established by the work of Lamarck, Lyell, and Darwin? Earth and its life are ancient and ever-changing; fossils document the evolution of life-forms over time.
Which best describes the fossil record? The fossil record is the highly ordered sequence in which fossils are found in layers of sedimentary rock.
The forelimbs of humans, cats, and bats have a number of detailed similarities in their construction. What best explains these similarities? The forelimbs are similar because all of these organisms inherited the basic forelimb design from a common ancestor
Variation among _____ within a _____ makes microevolution possible individuals … population
According to the Hardy-Weinberg principle, the frequencies of alleles in a population will remain constant if _____ is the only process that affects the gene pool. sexual reproduction
A population of small fish live in a lake with a sandy bottom that gives it a mottled look. The major predator is a bird that hunts by sight. Most of the fish are light sandy brown, but 10% are mottled and is heritable. Which of these statements is most a The proportion of mottled fish will increase over time.
Which best describes how an organism’s Darwinian fitness is measured? the organism’s reproductive success relative to other individuals in the same population
Blue poppies native to China are grown at a plant-breeding center in California, where those with the thickest leaves survive and reproduce best in the drier climate. This evolutionary adaptation of the poppies to their new environment is due to ____ directional selection
Certain bacterial strains have traits that allow them to resist the effects of antibiotic drugs. How do the resistance traits arise in a bacterial population, and under what circumstances will the resistance traits be most common? The resistance traits are produced by chance mutations and are present to varying degrees in most bacterial populations. Resistance traits will be most prevalent, however, in bacteria that are chronically exposed to antibiotic drugs.
An adaptation is _____. a heritable trait that confers a reproductive advantage on the individual possessing it
Which of the following is a true statement about Charles Darwin? He proposed natural selection as the mechanism of evolution.
At the time Darwin voyaged on HMS Beagle, the popularly accepted theory in Europe that explained the origin of Earth’s plants and animals held that the various species _____. had been created rapidly by a divine creator a few thousand years before
What was significant to Darwin about the fauna and flora of the Galápagos Islands? The species were similar to South American species, indicating common descent, but they had been extensively modified and were well-adapted to island life.
German shorthaired pointers, Scottish terriers, and Beagles are capable of interbreeding and producing viable, fertile offspring. The diversity seen in these breeds of dogs is the result of _____. artificial selection
Which of the following contradicts Darwin’s views? Earth is about 6,000 years old.
The breeding by humans of plants and animals with desired traits is called _____. artificial selection
If members of a population have traits that are both heritable and variable among individuals, then _____. advantageous traits will probably become more widespread in subsequent generations
Darwin inferred that there is a struggle for existence in which each individual’s odds of surviving to reproduce are quite poor, based on the observation that _____. natural population sizes usually stay about the same over long periods of time
“Differential success in reproduction” is the essence of _____. natural selection
In natural selection, _____ determine which phenotypes are successful. current conditions in the local environment
Fewer insects are killed today because many mosquitoes today are descendants of mosquitoes with insecticide-resistant characteristics
Experiments and observations indicate that natural selection acts _____. fairly quickly in some circumstances (within a few generations), and often temporarily in response to changes in the immediate environment
When they were first sold, insecticides were highly effective in killing mosquitoes. Today, a much smaller proportion of these insects die when sprayed with the same chemicals. Fewer insects are killed today because _____. a few mosquitoes were probably resistant to the insecticide before it was used. These survived to reproduce and are now the norm in populations that have been exposed to the chemical
Fossils are most likely to be found in _____. sedimentary rock
Which best summarizes the order of appearance of major life-forms (from earliest to most recent) and the time at which life first appeared as documented by the fossil record? prokaryotes, unicellular eukaryotes, multicellular eukaryotes, with the oldest life-forms appearing about 3.5 billion years ago
Evidence from molecular biology supports the theory of evolution by showing that _____. diverse organisms share many similar genes and proteins, and the similarity of these molecules is greatest when comparing closely related organisms
All known organisms use genetic information to produce protein molecules via the same genetic code. This finding strongly supports the hypothesis that _____. all organisms are descended from one or a few common ancestors
The bones of the wings of bats are homologous to the bones of the _____ of their ancestors front limbs
An important challenge to traditional ideas about species was the observation that seemingly dissimilar organisms, such as hummingbirds, humans, and whales, have similar skeletal structures. This most directly suggested to biologists that _____ dissimilar organisms might have evolved from a distant, common ancestor
Organisms that possess homologous structures probably _____ share a common ancestor that also had this structure
Members of the same population _____. share a common gene pool.
A population is _____. a group of individuals of the same species occupying a given area
The smallest unit that can evolve is a _____. population
Mutation plays a large role in the microevolution of bacterial populations. Why? Bacteria multiply very rapidly, and they are haploid so that a mutant allele will immediately have a full effect on the phenotype.
The major weakness of Darwin’s theory of descent with modification by natural selection (as it existed in 1859) was that it could notexplain _____. how advantageous traits arise and how they are passed to offspring
_____ and _____ generate variation in populations. Mutation … sexual recombination
Sexual recombination occurs when chromosomes are shuffled in _____ and fertilization. meiosis
The original source of all genetic variation is _____. mutation
Genetic variation in a population of animals or plants depends mainly on which of the following? sexual recomination
If a population is in Hardy-Weinberg equilibrium and remains in equilibrium, which of the following will be true? the frequency of homozygous dominants
In a large population of monkeys, the frequency of the recessive allele is 0.1. There is no migration and no selection. What is the frequency of the dominant allele? Assume that there are two alleles of this gene. 90%
Which of the following conditions would prevent a population from remaining in Hardy-Weinberg equilibrium? sexual selection
A moth population is at Hardy-Weinberg equilibrium. Which, if any, of the following conditions would tend to disturb Hardy-Weinberg equilibrium? The population consists of only six breeding pairs.
Approximately one out of every 2,500 Caucasians in the United States is born with the recessive disease cystic fibrosis. According to the Hardy-Weinberg equilibrium equation, approximately how many people are carriers? 1 in 25
What is the term for a change in the relative frequencies of alleles in a population over several generations? microevolution
Which of the following scenarios would most likely result in the microevolution of a population of humans? A colony of twelve humans is established on the moon and remains isolated from Earth.
Variation among _____ within a _____ makes microevolution possible individuals … population
Which of the following is the best example of gene flow? Wind blows pollen from one population of plants to another, and cross-fertilization occurs.
If a volcanic eruption killed all of the lizards on an island except for a tiny group of survivors, this event would probably cause _____. genetic drift through a bottleneck effect
Each of us is part of the ongoing evolution of the human species. Which of the following forms of microevolution is currently most important in human populations worldwide? Global travel and migration are promoting gene flow on an unprecedented scale.
The evolutionary effects of genetic drift are greatest when _____. the population size is small
The severe reduction in genetic variability seen in the endangered cheetah is probably attributable to _____. having gone through at least one bottleneck
Which of the following most accurately and directly measures an organism’s Darwinian fitness compared to other individuals in the same population? how many fertile offspring it produces
In a large population of randomly breeding individuals, the frequency of a recessive allele is initially 0.3. There is no migration and no selection. Humans enter this ecosystem and selectively hunt individuals showing the dominant trait. When the gene fr the frequency of the individuals who express the dominant phenotype will go down, and the frequency of homozygous recessive individuals will go up
In a population of bears, which is most likely to be considered to have the greatest Darwinian fitness? the bear that leaves the most descendants
Biologists often use the term fitness when speaking of evolution. Below are descriptions of four male grizzly bears. According to your understanding of evolution, which bear would biologists consider the most fit? Sandy
To be successful in evolutionary terms, an organism must _____. pass its genes on to the next generation
Which of the following changes in the gene pool results in an adaptation to the environment? natural selection
A geneticist studied a grass population growing in an area of erratic rainfall and found that plants with alleles for curled leaves reproduced better in dry years, and plants with alleles for flat leaves reproduced better in wet years. This situation woul preserve the variability in the grass population
Critics sometimes claim that the theory of evolution is flawed because it is based on random changes: mutations. They say that a random change in an organism is likely to harm it, not make it function better. What statement refutes these critics? Mutation is random; natural selection is not
A large population of brown and gray mice are isolated on an island. Their fur colors closely match the gray rock outcrops and brown soils of the island. Hawks are their main predators. This situation most likely reflects the outcome of _____. disruptive natural selection
Natural selection primarily acts on _____. phenotypes
Stabilizing selection _____. favors intermediate phenotypes in a population
Birds with average-sized wings survived a severe storm more successfully than other birds in the same population with longer or shorter wings. This illustrates _____. stabilizing selection
A population of squirrels is preyed on by small hawks. The smaller squirrels can escape into burrows. The larger squirrels can fight off the hawks. After several generations, the squirrels in the area tend to be very small or very large. What process is t disruptive selection
Selection that acts, over evolutionary time, to enhance traits that increase an individual’s ability to mate frequently or with quality partners is known as _____. sexual selection
Which would be a good example of intrasexual selection? Male elephant seals use their huge bodies to batter each other in battles for access to mates.
Antibiotic resistance in bacteria is an example of which of the following? directional selection
Scientists have warned doctors of the danger of their increasing use of antibiotics for treating minor illnesses. They are concerned because _____. strains of bacteria that are resistant to these drugs will become more widespread
How does the overuse of antibiotics in medicine and agriculture contribute to a major public health threat? Indiscriminant use of antibiotics selects for resistant bacteria.
Under some conditions, heterozygotes have greater reproductive success than homozygotes. What is this called? heterozygote advantage
Which of the following would seem to be an example of neutral variation? human fingerprint patterns
Sickle-cell disease is a debilitating disease that results from being homozygous recessive for the “sickle-cell allele” of a hemoglobin gene. Why is the allele present and even common in many human populations? The sickle-cell allele confers malaria resistance to heterozygotes. In some regions where malaria is common, heterozygotes have an advantage, and their reproductive success maintains the recessive allele at a high frequency in the population.
Which of the following statements best describes how the process of natural selection works? Better-adapted individuals will leave behind more offspring to carry on their genes, producing a dynamic “fit” between a population and its changing environment.
Which of the following is a misconception regarding natural selection? Natural selection progressively refines organisms’ adaptations, eventually leading to perfection.
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