BIO 2nd Test 1442

Which of the following can evolve?

Populations

Natural selection can act on a certain trait only if the trait is

heritable

The theory of natural selection states that

the individuals best suited to their environment contribute the most genes to the next generation.

Most commercial pesticides are effective for only 2 or 3 years because

those pests born with mutations that provide immunity will survive and reproduce.

Guppies exhibit sexual dimorphism in some pools due to intersexual selection, but the frequency of brightly colored males in a population varies depending on environmental factors such as the presence or absence of predators in the pool. Which of the following would you expect to occur in a captive population of guppies collected from Trinidad, if you allowed them to breed for many generations in an aquarium WITHOUT predators?

Male guppies that are brightly colored will have better reproductive success than dull males.

During a study session about evolution, one of your fellow students 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 the following descriptions illustrates phenotype variation caused by environmental factors?

diet of caterpillars changes their morphology

Once upon a time, most of the male guppies in a predator-free pool were brightly colored. Then a predator invaded the pool, and several generations later the males are similar in coloration to the mostly gray females. Which term best describes the inconspicuous coloration of male guppies in pools containing visual predators?

evolutionary adaptation

A change in the genetic makeup of a population is called?

evolution

Bright coloration in birds makes them stand out to predators. In female birds that sit on the nest, bright coloration is rare. This is likely the result of

natural selection

Imagine that a biologist develops a strain of corn with a lower fat content by choosing low. fat variants and crossbreeding them over several generations. This is an example of

artificial selection

The punctuated equilibrium model is best illustrated by an example of

gradual speciation

Dolphins (which are mammals) and sharks (which are fish) have stiff dorsal fins projecting from their backs that help them maneuver through water. These relationships of structures to each other are best described as

analogous structures

Having greater evolutionary fitness means

having more offspring

Which trait is the best example of an adaptation?

A mutation resulting in a heat-resistant enzyme in a bacterium living in a hot spring.

Boa constrictors (a type of snake) have tiny pelvic girdles and leg bones inside their bodies. Because these structures are nonfunctional "evolutionary baggage, they are called

Vestigial

An emu is a flightless bird that still has wings. These wings are an example of

vestigial structures

Parasitic Rhagoletis flies that show a preference for either hawthorn or apple trees (and are no longer interbreeding with populations found on the other host plant) illustrate the concept of

sympatric speciation

Two species of squirrels live on either side of the Grand Canyon. It is believed that a long time ago, before being separated by the canyon, they were the same species. This is an example of

allopatric speciation

Which term is used to describe the continued divergence of species based on the low fitness of hybrid offspring?

reinforcement

The biological concept of species requires that

organisms reproduce sexually

When a species invades a new habitat and evolves rapidly into several new species to better exploit new resources, what has occurred

adaptive radiation

The common edible frog of Europe is a hybrid between two species, Rana lessonge and Rana ridibunda. The hybrids were first described in 1758 and have a wide distribution, from France across central Europe to Russia. Both male and female hybrids exist, but when they mate among themselves, they are rarely successful in producing offspring. What can you infer from this information

Postzygotic isolation exists between the two frog species

How are two different species most likely to evolve from one ancestral species?

allopatrically, after the ancestral species has split into two populations

The vegetable we know as the potato resulted from naturally occurring genome doubling within one species. In other words, the potato has twice as many chromosomes as the ancestor it was derived from. The potato could therefore be described as being the result of the process known as

autopolyploidy

How can reproductive barriers form sympatric populations while their members remain in the same geographic area?

polyploidy

One species of fish feeds in the muddy bottom of a lake. A second species eats insects that land on the water surface. This is an example of

habitat isolation

A gametic barrier is an example of

a prezygotic isolating mechanism

Two species of pines, Pinus radiata and Pinus muricota, live in the same regions of California and are capable of forming hybrids under laboratory conditions. However, they do not interbreed because one releases pollen in February and the other in April. What genetic isolating mechanism is involved?

temporal isolation

In many species of fireflies, males flash light from their abdomens to attract females. Each species has a different flashing pattern. What genetic isolating mechanism is involved?

behavioral isolation

Homozygotes with two sickle-cell alleles are selected against because of mortality. However, heterozygotes for sickle-cell allele experience few effects from sickle-cell allele and are more likely to survive malaria. In regions with malaria, the net effect of this exposure produced evolutionary change by

increasing sickle-cell allele frequency

From an evolutionary point of view, what important process occurs when a young male baboon leaves the troop that he was born in to join another troop?

gene flow

Suppose a new mutation that improves metabolic efficiency is lost from a small population of mammals living in a region of seasonal food scarcity after a hurricane eliminates half the mammal population. This is an example of

genetic drift

When closely related individuals mate with each other, or inbreed, the offspring are often not as fit as the offspring of two unrelated individuals. Why?

Inbreeding can bring together rare, deleterious mutations that lead to harmful phenotypes.

The net migration of alleles into or out of a population from neighboring population is called

gene flow

Male fish that display a bright blue color attract more mates as well as more predators. Maintaining that blue gene in the population is an example of

sexual selection

Habitat loss, natural catastrophes, and/or excessive harvesting of a species often results in

Population bottlenecks

___is due to chance events that change the alleles frequencies in small population.

genetic drift

Imagine that one of the original four mice that escape from a research lab is blind due to a genetic defect. If most of the mice born in subsequent generations (of the escaped population) are blind from birth, this is most likely a case of

the founder effect

Which of the following is most likely to experience genetic drift?

a population of endangered birds that includes only five individuals

Which statement is most accurate?

Mutations occur at random and are by chance.

Mutations are important because they

provide variation that can result in evolutionary change

If the tallest and shortest individuals of a population of humans do not survive and reproduce as well as the individuals of "average" height, which type of selection would most likely result?

stabilizing selection

In one butterfly species, the colors of individuals range from white to black, with many shades of gray in between. If the butterflies in a mountain population become darker and darker in color over the course of several generations, what kind of evolutionary force is likely acting on the population?

directional selection

Anolis lizards are placed on small islands with no large trees. In just a few generations, lizards in the population exhibit shorter hind legs than their ancestors. This is an example of

directional selection

In one butterfly species, the colors of individuals range from white to black, with many shades of gray in between. If the butterflies in a mountain population become a similar shade of medium gray over the course of several generations, what kind of evolutionary force is likely acting on the population?

stabilizing selection

According to the Hardy-Weinberg principle, if 75% of the alleles in the gene pool are A1 and 25% are A2, what is the proportion of individuals with genotype A1A, in this population?

0.5625

The recessive allele b occurs with a frequency of 0.8 in a population of crabs that is in Hardy-Weinberg equilibrium. What is the frequency of individuals that are homozygous dominant (BB)?

0.04

In corn, purple kernels are dominant to yellow. A random sample of 100 kernels is taken from a population in Hardy-Weinberg equilibrium. It is found that 9 kernels are yellow and 91 kernels are purple. What is the frequency of the yellow allele?

0.3

Cystic fibrosis is a genetic disorder in homozygous recessives that causes death during the teenage years. If 1 in 2,500 newborn babies have the disease, what are the expected frequencies of the dominant (A1) and recessive (A2) alleles according to the Hardy- Weinberg model?

f(A1)=0.996, f(A2) = 0.004

A population is at Hardy-Weinberg equilibrium for two alleles, A1 and A2. The frequency of the allele A2 is 0.3. What is the frequency of individuals that are heterozygous?

0.42

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.1. What is the frequency of individuals with aa genotype?

0.01

Within a large population, if no mutations occur, no migration occurs, all matings are random, and each individual has an equal chance of reproducing, which of the following will probably happen?

No evolution will occur

Deviations from the Hardy-Weinberg equilibrium

occur when evolutionary forces are operating on the population

If you are studying a small fish population in the lab, which Hardy-Weinberg condition is easiest to meet?

no gene flow

Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus

the allele's frequency should not change from one generation to the next.

Logically, which of these should cast the most doubt on the relationships depicted by an evolutionary tree?

Relationships between DNA sequences among the species did not match relationships between skeletal patterns.

Which of the following best describes the rationale for applying the principle of maximum parsimony in constructing phylogenetic trees?

Similarity due to common ancestry should be more common than similarity due to convergent evolution.

The wasp genus Nasonia contains all of the descendants of the common ancestor of its members. This genus therefore would be called

a clade

Which of the following statements is accurate with regard to a phylogeny, as represented by a phylogenetic tree

Members of a clade likely share many derived characters.

A portion of a phylogenetic tree in which scientists have not definitively determined all of the relationships

polytomy

The more recently two species have diverged, the more similar their DNA (and protein) sequences should be. This principle is most directly related to

a molecular clock

When using systematics to build a hypothesis of relatedness represented by a phylogenetic tree, which of the following is considered most important for classification?

shared derived characters

What is true about organisms that are a part of the same clade?

They evolved from a shared ancestor.

Only the following insect groups exhibit complete metamorphosis: Coleoptera, Hymenoptera, Lepidoptera, and Diptera. According to the phylogeny above, complete metamorphosis appears to be a ___ of these groups.

shared derived character

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 homologous genes or features with each other than either does with species Z

The highlighted region (P.Q.R) represents a

paraphyletic group

According to the figure above, which group is more closely related to the butterflies and moths?

flies

Consider five species of toads. Species A and B are sister species. Species C and D are also sister species. The clade containing species A and B is a sister to the clade containing species C and D. Which species is most likely to have the greatest number of shared derived characters in common with species A?

Species B

Transformation:

bacteria takes up naked DNA from other organisms

Transduction:

a virus transfers the genes from one organism to another

Conjugation:

a hollow tube, or pilus transfers genes between bacteria

Endosymbiosis:

a historical event in which one cell was engulfed by another, leading eventually to a new type of organism

Which of the following statements about horizontal gene transfer is accurate?

Horizontal gene transfer was quite common in the early stages of evolution of life on Earth.

Which of the following is NOT a mechanism for horizontal gene transfer?

binary fission

Which statement is true?

Viruses are not cellular organisms.

Which is NOT a potential strategy to combat a human virus such as SARS CoV-2?

phage therapy

Prions such as the infectious agent that causes "mad cow" disease (Bovine Spongiform Encephalopathy) are composed of

proteins

Human diseases can be caused by

all types of viruses.

What is a primary goal associated with bioremediation?

to clean up areas polluted with toxic compounds by using bacteria

This term describes an organism that obtains both carbon and energy by ingesting other organisms.

heterotroph

In general, what is the primary ecological role of prokaryotes?

breaking down organic matter

Which of the following is an important source of endotoxin in gram-negative species?

cell wall

Modern geologist estimate that the age of Earth is about

4.5 billion years

Scientist hypothesize that prokaryotes evolved before eukaryotes because

the oldest fossilized cells represent prokaryotes

Theories on the atmosphere of early Earth indicate that it lacked

O2

The earliest fossil organisms resemble modern

prokaryotes

The first molecular oxygen present in Earth's atmosphere was likely produced by organisms very similar to modern

cyanobacteria.

How were conditions on the early Earth of more than 3 billion years ago different from those on today's Earth?

Less ultraviolet radiation penetrated early Earth's atmosphere.

The atmosphere of early Earth did not contain molecular Oxygen (02).

If the early Earth's atmosphere contained little or no 02, then where did most of the 02 in our modern atmosphere come from?

photosynthesis

The oldest fossil organisms (stromatolites) presently known have been dated at approximately how many years old?

3.5 billion

In which habitat are you most likely to find chemoautotrophic prokaryotes?

in hydrothermal vents

Which is the correct series of events in the evolution of life on Earth?

Photosynthesis → 02 → aerobic metabolism

Since the Pleistocene ice age, deserts have been gradually forming in the southwestern United States. As the original lakes and rivers of this area shrank into isolated streams, ponds, and springs, the fishes living in them developed a strong potential for

speciation

A bacterial allele that provides resistance to the antibiotic streptomycin is

beneficial to the cell in the presence of streptomycin

On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences.

Which two of the following have operated to increase divergence between mosquitofish populations on Andros?

III. sexual selection

V. natural selection

Variation in a gene pool is increased when

alleles are introduced by immigration from another population

An elaborate, species-specific courtship dance or call is an adaptation that may result in increased fitness for the mating animals (especially the female). Which pair of key terms are most relevant to this scenario

sexual selection and behavioral isolation

Based on the way natural selection works, what is the best way to make use of antibacterial soap?

Use it only when you need to be free of bacterial contamination, so bacteria will be less likely to evolve resistance to it.

Which of the following factors would NOT contribute to allopatric speciation?

Gene flow between the two populations is extensive.