Chapter 13 Mastering Bio

Biogeography

-unique collection of marsupial mammals in Australia -resemblance of island species to nearby mainland species

Environmental change Selective pressure Change in population

1- A drought causes an habitat to turn dry and brown 2- Green beetles are more visible to birds than brown beetles, so birds eat more green beetles 3-Brown beetles survive to reproduce more than green beetles do. The Brown allele increases in frequency

In human gamete production there is an average of _____ crossover events per chromosome pair.

2-3

Of the scenarios below, which represents the occurrence of evolution at its smallest scale?

A pesticide spray is heavily used on a particular farm. Initially it kills 98% of the grasshoppers on contact. Over several generations, the local grasshopper population becomes resistant to the pesticide through inheritance of resistance alleles. Other nearby grasshopper populations do not change in any noticeable way.

Which of these individuals is a homozygous genotype?

AA

In a species of snail, dark-shelled individuals are better hidden from bird predators in the shady forest, while light-shelled individuals are better hidden in well-lit brushy edge areas. If there were no areas of intermediate brightness in this habitat,which type of selection would act on shell color in these snails?

Disruptive selection

Which option best describes the concept of an evolutionary tree diagram?

Evolutionary trees relate species to each other by ancestry. An ancestor common to all of the species is placed at the root of the tree. Branch points are defined by homologous features that are shared by the descendant species along a particular branch.

True or False. In the example described in the tutorial, the red amoebas survived the catastrophic event, and all future generations of amoebas were red because the red amoebas had a higher reproductive rate than the blue ones.

False

What usually occurs during intersexual selection?

Females usually choose males with whom to mate.

Color is an inherited trait in beetles. If brown beetles move into a population from a nearby island, which of the following statements is correct?

Gene flow causes the frequency of the brown allele to increase.

Remember that color is an inherited trait in beetles. Which of the following is an example of natural selection?

Green beetles leave more offspring than brown beetles because they are better at finding food

Which statement reflects a possible weakness of the fossil record?

Many species probably did not die in the right place at the right time to be captured in fossils, and many fossils will never by found by paleontologists.

Sometimes critics charge that evolution is based on mere speculation because it cannot be directly observed or experimentally induced. Is this true of evolution by natural selection?

Natural selection changes the traits of some organisms quite quickly, in ways that are clearly adaptive. Scientists have documented such changes in thousands of studies.

Which condition would disturb the Hardy-Weinberg equilibrium and cause the gene pool to change?

Several homozygous recessive individuals leave the population.

Which genotype relative to the sickle-cell allele has the greatest reproductive success in regions where malaria is a common disease?

the heterozygous genotype

In a population with brown and green alleles for color, genetic drift

has more effect on the evolution of a small population.

Genetic drift is a process based on _____.

the role of chance

Which choice contributes the most to genetic variation among individuals in most prokaryote species?

mutation

In sexual selection, individuals with certain inherited characteristics are more likely to obtain mates than other individuals. This often results in _____ , differences between the sexes in size, appearance, and behavior.

sexual dimorphism

Small lizards have difficulty defending their territory, but large lizards are more likely to be preyed upon by owls. Which type of selection would act on body size in these lizards under these conditions?

stabilizing selection

____ favors intermediate phenotypes, selecting against phenotypes at both ends of a range and reducing variation.

stabilizing selection

If color is an inherited trait in beetles, and birds are more likely to eat brown beetles than green beetles,

the frequency of the green allele will increase.

A mutation occurs when _____.

there is a change in the DNA sequence of a gene

Observation of natural selection in action

-development of pesticide resistance in insects -changes in average beak size in finches following dry or wet years

Fossil record

-discovery of bones from many different dinosaur species -transitional forms that link whales with land-dwelling ancestors that are now extinct

Anatomical and Molecular Homologies

-same genetic language of DNA and similar genes in yeasts, fruit flies, and humans -similar forelimb anatomy in different species of mammals

Environment change Selective pressure Change in population

1. Pesticide is applied to a population of insects 2. Some insects have a gene that makes them resistant to the pesticide. These insects survive. Insects without the gene die. 3. The surviving insects reproduce. The frequency of resistant insects in the population increases.

In artificial selection, humans provide the selective pressure for species to change and shape the evolution of various breeds. What provides the selective pressure in natural selection?

the environment

The evolution of populations due to chance is

genetic drift

In a type of sexual selection often called ______, individuals of one sex (usually females) are choosy in selecting their mates. This choice is often based on the showy appearance or behavior of the male.

mate choice

Crossing over, resulting in an increase in genetic variation, occurs between _____.

nonsister chromatids of homologous chromosomes

Generation-to-generation change in the allele frequencies in a population is _____.

microevolution

Genetic drift is ____.

more likely to have an impact on small populations

How are adaptations beneficial to organisms?

Adaptations help organisms survive and reproduce in a particular environment.

Suppose that every few years, all people over 6 feet tall do not have any children. How will this affect the human population?

Alleles that promote "tallness" will decrease in frequency.

Which of these gametes contain one or more recombinant chromosomes?

B, C, F, and G

Why was Darwin's acceptance of an ancient, continuously changing Earth so important in his development of his ideas about evolution?

Darwin hypothesized that species changed gradually, over long spans of time, in response to diverse and changing habitats.

favors phenotypes at one end of a range and is common in periods of environmental change

Directional Selection

favors phenotypes at one end of a range and is common in periods of environmental change.

Disruptive Selection

Which of the following events could NOT be caused by a population bottleneck?

Increased population size

Which example below presents a misconception about how antibiotic resistance develops?

Individual bacteria and viruses become immune to antibiotics after they are exposed to them. Eventually the antibiotics are useless.

Which of the following statements about the amoeba population described at the end of the tutorial is true?

It is more vulnerable to extinction due to lack of genetic variation.

In the normal course of evolution and adaptation, what is the most likely way for wings to develop in a tetrapod (four-limbed organism)?

The forelimbs (or possibly hind limbs) will be used for the new purpose of flight. This new function will arise through many gradual and uncertain steps, and there will be aspects of the wing that reflect its history and are not perfectly suited for flight.

Consider a hypothetical insect population of 100 individuals. Two equally represented alleles (A and a) exist for a particular gene. Which scenario is an example of microevolution in this population?

The population is exposed to a toxin that kills individuals with the A allele. After exposure to the toxin the population has 25 surviving individuals, and 95% of them have the aa genotype.

Which of the following is true of homologous structures?

They are structurally similar due to inheritance from a common ancestor.

The frequency of a particular lethal recessive allele in a population is 0.02. Given this information, calculate the percentage of individuals who are carriers of the lethal recessive allele.

approximately 4%

The Illinois populations of the greater prairie chicken benefited when managers brought in prairie chickens from other populations. This restored genetic variation to the Illinois populations through the process of _____.

gene flow

The ease with which humans travel across the globe is likely to increase _____.

gene flow

All the genes in a population are that population's _____.

gene pool

Modern travel along with migration reduces the probability of _____ having an effect on the evolution of humans.

genetic drift

_____ is a type of sexual selection in which individuals of one sex (usually males) compete directly for mates. This may involve ritualized displays or physical combat.

intrasexual selection

Homologous pairs of chromosomes are lined up independently of other such pairs during _____.

metaphase 1

Which of the following are causes of evolutionary change?

natural selection mutation genetic drift gene flow