evolution learnsmart
Which is an example of mimicry?
A harmless California kingsnake has color patterns similar to those of the poisonous western coral snake.
All of the following are examples of prezygotic isolating mechanisms except:
A lion and a tiger are considered separate species because even though they can mate, the offspring is sterile.
Which is an example of a postzygotic isolating mechanism?
A lion and a tiger are considered separate species because even though they can mate, the offspring is sterile.
Which is a trait shaped by natural selection that increases an organism's reproductive success?
Adaptation
_____________ ______________ also called divergent evolution, can occur in a relatively short time when one species gives rise to many species in response to the creation of a new habitat or another ecological opportunity
Adaptive radiation
_______________ _______________ of mammals at the beginning of the Cenozoic era following the extinction of dinosaurs likely produced the diversity of mammals visible today.
Adaptive radiation
In ______________ speciation, a physical barrier divides one population into two or more populations.
Allopatric
true statements
Almost every specimen that Darwin had collected on the Galápagos Islands was new to European scientists. The new species most closely resembled species from mainland South America, although the Galápagos and the mainland had different environments. Island and mainland species should not have resembled one another so closely unless the mainland populations changed after reaching the Galápagos.
Which statements about vertebrate embryos are true?
Although the adult forms differ, the shared features in the embryos suggest that vertebrates evolved from a shared ancestor. In fish, pharyngeal pouches develop into gills. In reptiles, birds, and mammals, these structures become parts of the ears, jaws, and throats. All vertebrate embryos have a tail and paired structures called pharyngeal pouches.
Which structures can be used for the same purpose and can be superficially similar in construction but are not inherited from a common ancestor?
Analogous structures
Which statements about morphology as evidence of evolution are true?
Analogous structures show that functionally similar features can evolve independently in similar environments. Evolution predicts that an organism's body parts are more likely to be modifications of ancestral body parts than they are to be new features. Evolution predicts that ancestral features that no longer have a function will become smaller over time until they are lost.
Which are traits that are more primitive features, such as teeth and tails, that appear in ancestral forms?
Ancestral traits
Which occurs when a population declines to a very low number and then rebounds?
Bottleneck
Which is a morphological adaptation that allows an organism to blend in with its environment?
Camouflage
Transitional fossils provide detailed patterns of evolutionary change for the ancestors of many modern animals. Which is an example of a transitional fossil?
Certain dinosaur fossils, such as Archaeopteryx, show feathers of modern birds and teeth and bony tails of reptiles.
Which did Darwin infer after observing artificial selection?
Darwin also thought that, given enough time, perhaps this process could produce new species. Darwin inferred that if humans could change species by artificial selection, then perhaps the same process could work in nature.
If an extreme version of a trait makes an organism more fit, which type of selection might occur?
Directional selection
Until the mid-1850s, nearly all peppered moths in England had light-colored bodies and wings. Beginning around 1850, however, dark moths began appearing. By the early 1900s, nearly all peppered moths were dark. The darker the moth, the more it matched the sooty background of its tree habitat, and the harder it was for predators to see. Thus, more dark moths survived, adding more genes for dark color to the population. This is an example of which type of selection?
Directional selection
Snakes living on the mainland shores inhabit grasslands and have mottled brown skin. Snakes inhabiting rocky island shores have gray skin. Each is adapted to its particular environment. A snake with intermediate coloring would be disadvantaged because it would be more visible to predators. This is an example of which type of natural selection?
Disruptive selection
Which is a process that splits a population into two groups by removing individuals with average traits but retaining individuals expressing extreme traits at both ends of a continuum?
Disruptive selection
Which is an early, prebirth stage of an organism's development?
Embryo
Which statements about convergent evolution are true?
Examples of convergent evolution include the evolution of Australian marsupials and the placental mammals on other continents. Sometimes unrelated species evolve similar traits even though they live in different parts of the world. This is called convergent evolution. Convergent evolution occurs in environments that are geographically far apart but have similar ecology and climate.
Which can occur when a small sample of a population settles in a location separated from the rest of the population?
Founder effect
Select the statements that are true.
Gould and Lewontin made the point in 1979 in a paper that not all features of an organism are necessarily adaptive. Gould and Lewontin claimed that biologists tended to overemphasize the importance of adaptations in evolution.
Which explains that when allelic frequencies remain constant, a population is in genetic equilibrium?
Hardy-Weinberg principle
Which describe how Darwin arrived at his theory of evolution?
He considered the theories of others. He considered the observations he made.
Which describe some of the activities Darwin did on his voyage on the HMS Beagle?
He observed fossils of marine life at high elevations. He made extensive collections of rocks, fossils, plants, and animals.
Which are anatomical structures inherited from a common ancestor?
Homologous structures
Select statements about gene flow that are true.
In reality, few populations are isolated. Migration, increases genetic variation within a population and reduces differences between populations. A population in genetic equilibrium experiences no gene flow.
Which are true of the spandrel example used by Gould and Lewontin?
In reality, spandrels are an unavoidable consequence of arch construction. Because spandrels are often decorative, one might think that spandrels exist for decoration.
Which are the four principles of natural selection?
Individuals in a population have variations. Variations that increase reproductive success will have a greater chance of being passed on than those that do not increase reproductive success. Organisms have more offspring than can survive on available resources. Variations can be inherited.
Which describes how adaptation affects an organism?
It increases its chance of survival.
Which is true of gene flow?
Migration increases gene flow between populations.
Which is an example of adaptive radiation?
More than 300 species of cichlid fishes once lived in Lake Victoria. These species diverged from a single ancestor within the last 14,000 years.
How can natural selection change a population?
Natural selection can modify a population if variations that increase reproductive success continue to be passed on to future generations.
Which statement describes natural selection and evolution?
Natural selection is a mechanism by which evolution occurs.
Which statements are true regarding the development of antibiotics?
One unintended consequence of the continued development of antibiotics is that some diseases have re-emerged in more harmful forms. For almost every antibiotic, at least one species of resistant bacteria exists.
A type of reproductive isolating mechanism that prevents gene flow among populations which operates afterfertilization occurs is called _____________ _____________ mechanism.
Postzygotic isolating
Which type of reproductive isolating mechanism prevents gene flow among populations after fertilization occurs?
Postzygotic isolation mechanism
Which type of reproductive isolating mechanism prevents gene flow among populations before fertilization occurs?
Prezygotic isolating mechanism
Darwin read Charles Lyell's ____________ _____________ ____________, a book proposing that Earth was millions of years old.
Principles of geology
According to the theory of ___________ ___________, rapid spurts of genetic change cause species to diverge quickly; these periods punctuate much longer periods when the species exhibit little change.
Punctuated equilibrium
According to which theory do rapid spurts of genetic change cause species to diverge quickly?
Punctuated equilibrium
The bigger the tail of a male peacock, the more attractive the bird is to females. This is an example of which type of selection?
Sexual selection
Which is a type of natural selection, in which change in frequency of a trait is based on the ability to attract a mate?
Sexual selection
Which is the process whereby some members of a sexually reproducing population change so much that they can no longer produce fertile offspring with members of the original population?
Speciation
Which operates to eliminate extreme expressions of a trait when the average expression leads to higher fitness?
Stabilizing selection
Apple maggot flies appear to be diverging based on the type of fruit they eat. This is an example of which type of speciation?
Sympatric speciation
In which type of speciation does one species evolve into a new species without a physical barrier?
Sympatric speciation
Which is true about mutations?
The cumulative effect of mutations in a population might cause a change in allelic frequencies and thus violate genetic equilibrium. Occasionally a mutation provides an advantage to an organism. A mutation that provides an advantage will then be selected for and become more common in subsequent generations.
Select statements about the fossil record that are true.
The fossil record can show how ancient species are similar to current species. Fossils also show that some species, such as the horseshoe crab, have remained unchanged for millions of years. Transitional fossils provide detailed patterns of evolutionary change for the ancestors of many modern animals, including horses, whales, and humans.
What does evolutionary theory predict about molecules in species with a recent common ancestor?
The more closely related the species are, the greater the number of shared amino acid sequences.
Which is an example of analogous structures?
The wings of an eagle and the wings of a dragonfly
Which is not a condition that must be met for a population to be in Hardy-Weinberg equilibrium?
There must be natural selection
Which describe transitional fossils?
They have features shared by different species. They help to support the theory of evolution.
Which is true of mating within a population?
Usually, organisms mate with individuals in close proximity.
All of the following are ways in which natural selection alters phenotypes except:
adaptation
The better an organism is ______________ to its environment, the greater its chances of survival and reproductive success.
adapted
Which can occur in a relatively short time when one species gives rise to many species in response to the creation of a new habitat or another ecological opportunity?
adaptive radiation
Geographic barriers can include mountain ranges, channels between islands, wide rivers, and lava flows. The grand Canyon separates two populations of squirrels, the Kaibab squirrel and the Abert squirrel. While these animals officially belong to the same species, they demonstrate distinct differences and, in time, they might divergeenough to be classified as separate species. If they were to become separate species, this would be an example of ____________ speciation.
allopatric
The Kaibab squirrel is found on the Grand Canyon's north rim, while the Abert squirrel lives on the canyon's south rim. Scientists think that the two types of squirrels diverged from an ancestral species and today are reproductively isolated by the width of the canyon. While these animals officially belong to the same species, they demonstrate distinct differences and, in time, they might diverge enough to be classified as separate species. if this occurred, this would be an example of which type of speciation?
allopatric
_______________ structures can be used for the same purpose and can be superficially similar in construction but are not inherited from a common ancestor.
analogous
One unintended consequence of the continued development of _______________ is that some diseases, which were once thought to be contained, have re-emerged in more harmful forms.
antibiotics
The process of directed breeding to produce offspring with desired traits, referred to as selective breeding was called _______ by Darwin.
artificial selection
The process of directed breeding to produce offspring with desired traits, referred to as selective breeding was called _____________ ____________by Darwin.
artificial selection
Which is the study of the distribution of plants and animals on Earth?
biogeography
Many species evolve in close relationship with other species. The relationship might be so close that the evolution of one species affects the evolution of other species. This is called __________.
coevolution
Mutualism is one form of ____________.
coevolution
When a species evolves a relationship that is so close with another species that the evolution of one species affects the evolution of other species, this is called
coevolution
All of the following are examples of convergent evolution except:
comet orchids and the moths that pollinate them
Which fields of study offer evidence for evolution?
comparative biochemistry comparative anatomy fossil record embryology
Sometimes unrelated species evolve similar traits even though they live in different parts of the world. This is called ______________ evolution.
convergent
All of the following are morphological evidence for evolution except:
cytochrome c
Which traits are newly evolved features, such as feathers, that do not appear in the fossils of common ancestors?
derived traits
_____________ ______________ are newly evolved features, such as feathers, that do not appear in the fossils of common ancestors.
derived traits
Gould and Lewontin argued that some features in organisms are like spandrels because even though they are prominent, they do not increase reproductive success. Instead spandrels exist
due to an unavoidable consequence of arch construction.
The theory of ______________ states that all organisms on Earth descend with modifications from their ancestors.
evolution
Which is the cumulative changes in groups of organisms through time?
evolution
____________ is the cumulative changes in groups of organisms through time.
evolution
True or false: Before Darwin, no other people had suggested ideas about the origins of species.
false
True or false: Mating is usually completely random in a population.
false
Which is a measure of the relative contribution that an individual trait makes to the next generation?
fitness
_____________ is a measure of the relative contribution that an individual trait makes to the next generation. It often is measured as the number of reproductively viable offspring that an organism produces in the next generation.
fitness
In the United States, the Old Order Amish have a high frequency of six-finger dwarfism. All affected individuals can trace their ancestry back to one of the founders of the Order. This is an example of
founder effect
The __________ can occur when a small sample of a population settles in a location separated from the rest of the population.
founder effect
Any change in the allelic frequencies in a population that results from chance is called
genetic drift
Which is the name of the theory in which evolution proceeds in small, gradual steps?
gradualism
The more closely related two species are, the ____________ the number of amino acid sequences will be shared.
greater
According to the _____________-_____________ principle, when allelic frequencies remain constant, a population is in genetic equilibrium.
hardy weinberg
Humans give birth at a much earlier developmental stage than other primates do. This causes them to need increased care early in their lives. Many scientists think that the ___________ of human babies is a consequence of the evolution of big brains and upright posture.
helplessness
Although birds use their wings to fly and reptiles use their limbs to walk, bird wings and reptile forelimbs are similar in shape and construction. These two structures are examples of _______________ structures.
homologous
Anatomical structures inherited from a common ancestor are called _____________ structures.
homologous
The human forearm and horse forearm shown here are examples of
homologous structures
A population that has undergone a bottleneck may be so genetically similar, it would appear that they have _____________.
inbred
Which is a consequence of a population that has undergone a bottleneck?
low genetic diversity
Which is a morphological adaptation in which one species evolves to resemble another species?
mimicry
All of the following are examples of coevolution except:
more than 300 species of cichlid fish once lived in Lake Victoria; these species diverged from a single ancestor within the last 14,000 years
A _____________ is a random change in genetic material. A ____________ that provides an advantage to an organism will be selected for and become more common in subsequent generations, thus violating genetic equilibrium.
mutation, mutation
A mechanism based on the principles of variation, heritability, overproduction, and reproductive advantage by which evolution occurs is __________ ____________.
natural selection
Darwin reasoned that some competitors in the struggle for existence would be better equipped for survival than others. Those less equipped would die. This process is referred to as:
natural selection
Which is a mechanism by which evolution occurs?
natural selection
_____________ ____________ is a mechanism by which _______________ occurs.
natural selection, evolution
Darwin inferred that if humans could change species by artificial selection, then perhaps the same process could work in ___________.
nature
Which are conditions that must be met for a population to be in Hardy-Weinberg equilibrium?
no gene flow no natural selection no genetic drift no mutation
The average cardinal lays nine eggs each summer. If each baby cardinal survived and reproduced just once, it would take only seven years for the first pair to have produced one million birds. This is an example of which of the four principles of natural selection?
overproduction
The Hardy-Weinberg principle states that the allele frequencies in populations should be constant.
p + q = 1
The Hardy-Weinberg principle states that the allele frequencies in populations should be constant. This often is expressed as
p + q = 1
This equation allows a person to determine the equilibrium frequency of each genotype in the population: homozygous dominant, heterozygous, and homozygous recessive.
p2 + 2pq + q2 = 1
Evolution occurs at the ___________ level, with genes as the raw material.
population
Darwin thought that island and mainland species should not have resembled one another so closely unless,
populations from the mainland changed after reaching the Galápagos.
A type of reproductive isolating mechanism that prevents gene flow among populations which operates before fertilization occurs is called ___________ ____________ mechanism.
prezygotic isolating
The Eastern meadowlark and the Western meadowlark have overlapping ranges and are similar in appearance. These two species, however, use different mating songs and do not interbreed. This is an example of a ____________ ____________ mechanism.
prezygotic isolation
In _____________ selection, the males of a species evolve threatening characteristics that intimidate other males. This is common in species, such as elk and deer, where the male keeps a harem of females.
sexual
A type of natural selection, in which change in frequency of a trait is based on the ability to attract a mate is called ___________ __________.
sexual selection
Most scientists define ________________ as the process whereby some members of a sexually reproducing population change so much that they can no longer produce fertile offspring with members of the original population.
speciation
Human babies born with below-normal and above-normal birth weights have lower chances of survival than babies born with average weights. Therefore, birth weight varies little in human populations. This is an example of
stabilizing selection
Which are ways in which natural selection alters phenotypes in a population?
stabilizing selection disruptive selection directional selection sexual selection
Scientists think that ______________ happens fairly frequently in plants, especially through polyploidy. As a result, the plant is no longer able to interbreed with the main population.
sympatric
The theory of evolution states
that all organisms on Earth descend with modifications from their ancestors.
The helplessness of human babies at birth is a consequence of
the evolution of big brains and upright posture
All of the following are examples of vestigial structures except:
the forelimb of a porpoise
___________ fossils have features shared by different species.
transitional
True or false: In a 1979 paper, biologists Gould and Lewontin claimed that biologists tended to overemphasize the importance of adaptations in evolution.
true
True or false: Multiple fields of study offer evidence of evolution
true
True or false: Variations that increase reproductive success will have a greater chance of being passed on than those that do not increase reproductive success. Given enough time, natural selection could modify a population enough to produce a new species.
true
Individuals in a population are different from each other. For example, some sunflowers are shorter than others. This is an example of which of the four principles of natural selection?
variation
____________ structures are structures that have either a reduced function or no function in an adult organism.
vestigial
All vertebrate embryos have the following features except:
wings