Organismal Bio 1331, Exam 2; Ch. 25, Ch. 26, Ch.27

Which of the following is a correct restatement of Darwin's phrase "descent with modification"?

"Descent with modification" means that the species that exist today descended from other, preexisting species and that species change over time.

genetic variation

(1) The number and relative frequency of alleles present in a particular population. (2) The proportion of phenotypic variation in a trait that is due to genetic rather than environmental influences in a certain population in a certain environment.

evolution

(1) The theory that all organisms on Earth are related by common ancestry and that they have changed over time, and continue to change, via natural selection and other processes. (2) Any change in the genetic characteristics of a population over time, especially, a change in allele frequencies.

Hardy-Weinberg principle

A principle of population genetics stating that genotype frequencies in a large population do not change from generation to generation in the absence of evolutionary processes (e.g., mutation, gene flow, genetic drift, and selection), and nonrandom mating.

vestigial trait

A reduced or incompletely developed structure that has no function or reduced function, but is clearly similar to functioning organs or structures in closely related species.

genetic bottleneck

A reduction in allelic diversity resulting from a sudden reduction in the size of a large population (population bottleneck) due to a random event.

developmental homology

A similarity in embryonic form, or in the fate of embryonic tissues, that is due to inheritance from a common ancestor.

natural experiment

A situation in which a natural change in conditions enables comparisons of groups, rather than a manipulation of conditions by researchers.

extinct species

A species that has died out.

extant species

A species that is living today.

transitional feature

A trait that is intermediate between a condition observed in ancestral (older) species and the condition observed in derived (younger) species.

genetic correlation

A type of evolutionary constraint in which selection on one trait causes a change in another trait as well; may occur when the same gene(s) affect both traits.

sedimentary rock

A type of rock formed by gradual accumulation of sediment, particularly sand and mud, as in riverbeds and on the ocean floor. Most fossils are found in sedimentary rocks.

The Argentinean pampas are a type of _____.

Grassland

If two modern organisms last shared a common ancestor fifty million years ago, we expect that they _________.

Have fewer homologous structures than two modern organisms that last shared a common ancestor one million years ago.

Species in hot climates tend to _____ compared to species in cold climates.

Have larger surface-to-volume ratios

Which of the following statements is an accurate combination of postulates 1 and 2 of natural selection?

Heritable variation exists for traits among individuals in a population.

Does the ability of a Mycobacterium tuberculosis cell to infect a new host depend on its drug-resistant phenotype?

No, drug-susceptible cells and drug-resistant cells are equally likely to infect a new host.

Which conclusion cannot be drawn from the following graphs concerning different characteristics of medium ground finches over a 35-year period?

The Drought in 1977 caused many finches to die of starvation.

The best definition of biological fitness is __________.

The ability of an individual to successfully reproduce relative to other individuals in the population.

population thinking

The ability to analyze trait frequencies, event probabilities, and other attributes of populations of molecules, cells, or organisms.

Which of these is the extant (that is, living) species least related to species X?

Z and Y

genetic marker

A genetic locus that can be identified and traced in populations by laboratory techniques or by a distinctive visible phenotype.

balancing selection

A mode of natural selection in which no single allele is favored in all populations of a species at all times. Instead, there is a balance among alleles in terms of fitness and frequency.

disruptive selection

A mode of natural selection that favors extreme phenotypes at both ends of the range of phenotypic variation. Maintains overall genetic variation in a population. Compare with stabilizing selection and directional selection.

directional selection

A mode of natural selection that favors one extreme phenotype with the result that the average phenotype of a population changes in one direction. Generally reduces overall genetic variation in a population. Compare with disruptive selection and stabilizing selection.

frequency-dependent selection

A pattern of selection in which certain alleles are favored only when they are rare; a form of balancing selection.

phylogenetic tree

A branching diagram that depicts the evolutionary relationships among species or other taxa.

acclimation

A change in a study organism's phenotype that occurs in response to laboratory conditions.

The modern definition of evolution is: Evolution is ______________.

A change in allele frequencies in a population over time.

founder effect

A change in allele frequencies that often occurs when a new population is established from a small group of individuals (founder event) due to sampling error (i.e., the small group is not a representative sample of the source population).

acclimatization

A change in an individual's phenotype that occurs in response to a change in natural environmental conditions.

Prior to the work of geologists and biologists (like Darwin), the prevailing belief was that Earth is __________.

A few thousand years old, and populations are unchanging

fossil record

All of the fossils that have been found anywhere on Earth and that have been formally described in the scientific literature.

A group of boys work out, practice for long hours, and become very good at playing basketball. Which of the following statements is true?

All of their efforts won't influence evolution, because they haven't changed anything that is heritable.

gene pool

All the alleles of all the genes in a certain population.

ecological selection

Also known as environmental selection. A type of natural selection that favors individuals with heritable traits that enhance their ability to survive and reproduce in a certain physical and/or biological environment, excluding their ability to obtain a mate. Compare with sexual selection.

Artic toothfishes live in very cold water year-round. These fishes have genes that code for anti-freeze proteins. The production of anti-freeze proteins in these fish is an example of ___________.

An Adaptation

genetic drift

Any change in allele frequencies due to random events. Causes allele frequencies to drift up and down randomly over time, and eventually can lead to the fixation or loss of alleles.

Who proposed that organisms could be organized into a scale of nature?

Aristotle

Ch. 25

Ch. 25

Ch. 26

Ch. 26

During a study session about evolution, one of your fellow student's remarks. "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?

Characteristics acquired during an organism's life are generally not passed on through genes.

Which of these conditions are always true of populations evolving due to natural selection? Condition 1: The population must vary in traits that are heritable Condition 2: Some heritable traits must increase reproductive success Condition 3: Individuals pass on most traits that they acquire during their lifetime.

Conditions 1 and 2

His experiences with Fuegians and slavery convinced Darwin that differences among all peoples are primarily _____ differences.

Cultural

Which pair of scientists below would probably have agreed with the process that is depicted by this tree?

Darwin and Wallace

Concept Map!

Darwin and Wallace proposed the process of Natural selection -> occurs over time in populations ->vary in their heritable traits; AND consist of many individuals. Natural selection produces special traits called adaptations -> are heritable traits that increase fitness -> represents the reproductive success of individuals. Natural selection causes evolution. Artificial selection causes evolution.

What is considered Darwin's greatest contribution to science?

Darwin described the process of natural selection.

How do the theories of Lamarck and Darwin differ?

Darwin proposed that populations change; Lamarck proposed that individuals change

What three major lines of evidence did Darwin use to argue that species have changed through time?

Darwin's evidence was that (1) fossils frequently resemble species found in the same area today, (2) many species have gone extinct, and (3) vestigial traits are common.

Patagonia is a _____.

Desert

Why were the Galápagos Islands so important to Darwin's formulation of natural selection?

Each island in the Galápagos possessed unique species.

Which of these is a consequence of uniformitarianism?

Earth is very old.

During the drought of 1977, 84 percent of the medium ground finch population on Daphne Major disappeared. The individuals that survived had deeper beaks and were larger. Given that natural selection favored large individuals with deeper beaks, how can the presence of individuals with small, pointier beaks in 1983 be explained?

Even though the majority of birds after 1977 had deeper beaks, there was still variation in beak size in the population. As seed type and seed availability changed, birds with beaks suited to exploit abundant seeds had higher reproductive success.

On Daphne Major, the medium ground finches did not reproduce, and 84 percent died during the drought of 197. Did evolution occur during this time?

Even though there was no reproduction, because mortality was not random, evolution occurred.

At the fossil site at Punta Alta, Darwin found evidence of _____.

Extinction

Which phrase best reflects the relationship between natural selection and evolution?

Natural selection is a process that causes evolution to occur.

Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, which develop from similar embryonic tissues. These structural similarities are an example of _________.

Homology

Resistance to a wide variety of insecticides, fungicides, antibiotics, antiviral drugs, and herbicides has recently evolved in hundreds of insects, fungi, bacteria, viruses, and plants. Why?

Humans are altering the environments of these organisms, and populations of these organisms are evolving by natural selection.

Evolutionary trees such as this are properly understood by scientists to be ___________.

Hypotheses

If Darwin had been aware of genes and their typical mode of transmission to subsequent generations, with which statement would he most likely have been in agreement?

If natural selection can change gene frequency in a population over generations, given enough time and genetic diversity, then natural selection can cause sufficient genetic change to produce new species from old ones.

Typological thinking is based on the idea that species are unchanging types and that variations within species are unimportant or even misleading.

In the choices given above, the statement about women is the only statement that assumes all individuals are the same.

Which of the following statements best depicts population thinking?

Individual giraffes within a population have different neck lengths.

Which of the following statements is an accurate combination of postulates 3 and 4 of natural selection?

Individuals experience differential success in their ability to survive or reproduce.

It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that __________.

Island forms are descended from mainland forms

Why is Aristotle's great chain of beings an incorrect theory?

It is wrong because it did not recognize that species do change. • Aristotle proposed that species were organized into a sequence based on increased size and complexity, with humans at the top. He also claimed that the characteristics of species were fixed—they did not change through time. • The theory of evolution by natural selection makes two predictions about the nature of species: 1. Species change through time. 2. Species are related by common ancestry. Furthermore, no organism is considered to be better than another based on complexity or size.

In the mid-1900s, the Soviet geneticist Lysenko believed that his winter wheat plants, exposed to increasingly colder temperatures, would eventually give rise to more cold-tolerant winter wheat. Lysenko's attempts in this regard were most in agreement with the ideas of __________. (whom)

Lamarck

Lamarck proposed that evolution occurs by the inheritance of acquired characteristics. His theory of evolution can be summarized by the figure below. What is the main difference between Lamarck's view of evolution and Darwin's view of evolution? Hint: how is Darwin's phenology of organisms organized?

Lamarck's ideas correlate to an escalator of evolution. Lamarck proposed that organisms become more complex over time. Lamarck's view of evolution was progressive, in that simple organisms were constantly becoming more complex or "advanced" over time. Darwin's view was that evolution produces a tree of life, and individuals can become simpler or more complex depending on their environment.

Darwin's thinking while on the Beagle was greatly influenced by his reading of a book written by _____.

Lyell

Through time, the lineage that led to modern whales shows a change from four-limbed land animals to aquatic animals with two limbs that function as flippers. This change is best explained by __________.

Natural Selection

Darwin and Wallace were the first to propose ____________.

Natural selection as the mechanism of evolution

Developmental homologies most likely occur because__________.

Of genetic homologies

The Galápagos Islands are located _____.

Off the coast of Ecuador

Which statement restates the fact that rifampin resistance in M. tuberculosis is an adaptation?

Rifampin resistance is a heritable trait that increases the fitness of individuals compared to susceptible individuals

In a hypothetical environment, fishes called pike-cichlids are visual predators of large, adult algae-eating fish (in other words, they locate their prey by sight). The population of algae-eaters experiences predatory pressure from pike-cichlids. Which of the following is least likely to occur in the algae-eater population in future generations?

Selection for larger female algae-eaters, bearing broods composed of more, and larger, young

structural homology

Similarities in adult organismal structures (e.g., limbs, shells, flowers) that are due to inheritance from a common ancestor.

genetic homology

Similarity in DNA nucleotide sequences, RNA nucleotide sequences, or amino acid sequences due to inheritance from a common ancestor.

Currently, two extant elephant species (X and Y) are classified in the genus Loxodonta, and a third species (Z) is placed in the genus Elephas. Thus, which statement should be true?

Species X and Y share a greater number of homologies with each other than either does with species Z.

Which of the following statements describes the law of succession?

Species in the fossil record were succeeded in the same region by similar species.

In the United States today, about half of the corn crop is genetically engineered with a protein that is toxic to corn borers, an insect pest of corn. Which of the following conditions would be necessary for evolution of resistance to the toxic protein to occur in the corn borer?

The corn borer must have or generate (by mutation) heritable variation in resistance to the toxic protein. The resistant corn borers must survive better or reproduce more than nonresistant corn borers.

In the Andes, at elevations of 12,000 feet, Darwin collected fossilized marine shells. The existence of marine shells at this altitude provided evidence that _____.

The deposit had been gradually uplifted to its present location

Which of the following statements describes the evolution by natural selection of Mycobacterium tuberculosis bacteria in their new environment?

The drug-resistance trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin.

gene flow

The movement of alleles between populations; occurs when individuals leave one population, join another, and breed.

Fitness has a different meaning in the context of evolution than in everyday use. Which of the following would be a good measure of evolutionary fitness?

The number of children you produce that survive to adulthood

descent with modification

The phrase used by Darwin to describe his hypothesis of evolution by natural selection.

geologic time scale

The sequence of eons, eras, and periods used to describe the geologic history of Earth.

How did the theory of special creation differ from Darwin's theory of evolution by natural selection?

The theory of special creation proposed that species are independently created and immutable over time. Darwin observed that species are related and change over time.

You are studying a group of fossils, and you notice that a particular trait is present in the older fossils, but disappears in the more recent species. What does this mean?

This means that in more recent species, individuals without the trait had higher fitness.

True or false? It would be difficult to assess whether the drug-susceptible or drug-resistant phenotype in a population of Mycobacterium tuberculosis was more fit in an environment without antibiotics.

True

HIV's genome of RNA includes the code for reverse transcriptase (RT), an enzyme that acts early in infection to synthesize a DNA genome off of an RNA template. The HIV genome also codes for protease (PR), an enzyme that acts later in infection by cutting long viral polyproteins into smaller, functional proteins. Both RT and PR represent potential targets for antiretroviral drugs. Drugs called nucleoside analogs (NA) act against RT, whereas drugs called protease inhibitors (PI) act against PR. Which of the following represents the treatment option most likely to avoid the evolution of drug-resistant HIV (assuming no drug interactions or side effects)?

Using moderate doses of NA and two different PIs at the same time for several months

Which of these is the extant (that is, living) species most closely related to species X?

V

Which are the four postulates of natural selection?

Variation in population Heritable variation Selection Differential survival or reproduction

What are vestigial traits and do they support the idea of special creation or descent with modification?

Vestigial traits indicate that species change over time. This is an important pattern component of the theory of evolution and is inconsistent with the theory of special creation.

Why did Darwin document and describe vestigial traits?

Vestigial traits indicate that species change over time. This is an important pattern component of the theory of evolution and is inconsistent with the theory of special creation.

Which of the following scientists argued that variation among individuals allows evolution to occur?

Wallace

Which of the following statements is an example of typological thinking?

Women are shorter than men, have longer hair, and like to shop.

Which of the five common ancestors, labeled V-Z, is the common ancestor of the greatest number of species, both living and extinct?

X

Has evolution by natural selection recently occurred in populations of M. tuberculosis?

Yes, the frequency of the adaptive allele for drug resistance in M. tuberculosis has increased over time.

"Population thinking" is essential to the idea of natural selection. Rather than thinking of populations or species as sets of mostly identical individuals, Darwin and Wallace understood that a great deal of heritable variation occurs among individuals within populations. Which example best illustrates this idea?

You have a different eye color than your classmate.

Adaptation has a different meaning in the context of evolution than in everyday use. Which of the following is an example of an adaptation in the biological sense?

Your thumb is an adaptation for grasping objects.