Question 1

A individual has a spontaneous single nucleotide polymorphism within an intron region of a transcriptional regulator. Such a mutation is likely to

Accepted Answer

A)  be advantageous. 
B)  be deleterious. 
C)  result in an altered transcript. 
D)  be neither advantageous not deleterious. 
E)  be inherited and increase or decrease in populations in a predictable fashion. 
A)  be advantageous. 
B)  be deleterious. 
C)  result in an altered transcript. 
D)  be neither advantageous not deleterious. 
E)  be inherited and increase or decrease in populations in a predictable fashion.

Question 2

A river takes a new path and divides a species of skinks into two isolated populations. Climate changes gradually cause the river to dry up, bringing the two populations together again, but when individuals of the two populations mate, the resulting hybrids are sterile. This is an example of

Accepted Answer

A)  sympatric speciation. 
B)  allopolyploid speciation. 
C)  allopatric speciation. 
D)  parapatric speciation. 
E)  reproductive speciation. 
A)  sympatric speciation. 
B)  allopolyploid speciation. 
C)  allopatric speciation. 
D)  parapatric speciation. 
E)  reproductive speciation.

Question 3

Most genetic variation in populations results from

Accepted Answer

A)  mutation. 
B)  polyploidy. 
C)  natural selection. 
D)  environmental pressure. 
E)  recombination of existing alleles. 
A)  mutation. 
B)  polyploidy. 
C)  natural selection. 
D)  environmental pressure. 
E)  recombination of existing alleles.

Question 4

Most marine turtles in a small population have six large scales down the centre of their carapace; however, in each generation, a few have seven. Every year, females of a population of marine turtles come ashore to lay their eggs on a small coral atoll. Some turtles bury their eggs in 'nests' that they dig in the sand, just above the high-tide mark, while others dig their nests further inland. The females return to the sea immediately after burying their eggs and the eggs incubate in the sand for about 8 weeks. In one season, heavy seas accompanying a cyclone destroy 85 per cent of all turtle nests on the island. Some years later it is observed that very few turtles lay their eggs just above the high-tide mark; most lay their eggs well inland. It is also observed that the majority of the nesting females have seven central carapace scales.
The change in carapace morphology of the population is most likely the result of

Accepted Answer

A)  natural selection. 
B)  neutral selection. 
C)  genetic drift. 
D)  environmental adaptation. 
E)  Based on this information, it is impossible to say. 
A)  natural selection. 
B)  neutral selection. 
C)  genetic drift. 
D)  environmental adaptation. 
E)  Based on this information, it is impossible to say.

Question 5

Adaptation

Accepted Answer

A)  results from mutation in individual organisms. 
B)  is the increased production of offspring in each generation. 
C)  occurs when a trait increases the fitness of an organism in a particular environment. 
D)  results from genetic variation in the population. 
E)  All of the answers are correct. 
A)  results from mutation in individual organisms. 
B)  is the increased production of offspring in each generation. 
C)  occurs when a trait increases the fitness of an organism in a particular environment. 
D)  results from genetic variation in the population. 
E)  All of the answers are correct.

Question 6

Gene duplications

Accepted Answer

A)  arise due to the duplication of the chromosome set. 
B)  result in orthologous genes. 
C)  allow mutations to accumulate in one copy of the gene. 
D)  are detrimental. 
E)  result in the loss of viable offspring. 
A)  arise due to the duplication of the chromosome set. 
B)  result in orthologous genes. 
C)  allow mutations to accumulate in one copy of the gene. 
D)  are detrimental. 
E)  result in the loss of viable offspring.

Question 7

Sickle cell anaemia is a debilitating disease caused by a mutation in a haemoglobin gene. Homozygotes for this allele have decreased fitness and suffer haemolytic anaemia. However, the allele occurs at high frequencies in some populations because

Accepted Answer

A)  heterozygotes for the mutant allele have the same fitness as homozygotes for the normal allele. 
B)  homozygotes for this allele have a high reproductive capacity. 
C)  selection does not act to reduce this allele as haemolytic anaemia is not a problem in some populations. 
D)  heterozygotes for this allele have increased resistance to malaria than homozygotes with the normal allele. 
E)  there is very little difference in fitness between people with the mutant allele and those with the normal allele. 
A)  heterozygotes for the mutant allele have the same fitness as homozygotes for the normal allele. 
B)  homozygotes for this allele have a high reproductive capacity. 
C)  selection does not act to reduce this allele as haemolytic anaemia is not a problem in some populations. 
D)  heterozygotes for this allele have increased resistance to malaria than homozygotes with the normal allele. 
E)  there is very little difference in fitness between people with the mutant allele and those with the normal allele.

Question 8

A seabird living on a small island is born with a mutation that gives it a coloured patch on the top of its head. The mutation is dominant and appears to be neutral. Over the next twenty generations, the frequency of the 'head patch' allele should

Accepted Answer

A)  increase. 
B)  decrease. 
C)  remain the same. 
D)  disappear. 
E)  Based on this information, it is impossible to predict. 
A)  increase. 
B)  decrease. 
C)  remain the same. 
D)  disappear. 
E)  Based on this information, it is impossible to predict.

Question 9

Two genes are shown to be close together on the same chromosome. In regard to recombination, these two genes would be

Accepted Answer

A)  independently assorted. 
B)  readily amenable to crossing over. 
C)  shuffled. 
D)  linked. 
E)  localised loci. 
A)  independently assorted. 
B)  readily amenable to crossing over. 
C)  shuffled. 
D)  linked. 
E)  localised loci.

Question 10

In a population in Hardy-Weinberg equilibrium, one in a hundred people have the inherited ability to curl their tongue downwards in a particular fashion. If this trait is the recessive phenotype, what percentage of the population in the next generation is likely to be carriers of this allele, although unable to curl their tongues downwards?

Accepted Answer

A)  2 per cent 
B)  10 per cent 
C)  18 per cent 
D)  90 per cent 
E)  98 per cent 
A)  2 per cent 
B)  10 per cent 
C)  18 per cent 
D)  90 per cent 
E)  98 per cent

Question 11

Two species of yabbies inhabit the same mountain creek. They are morphologically indistinguishable but can be split into two groups according to presence or absence of a number of genetic markers in their mitochondrial DNA. When yabbies from the two groups interbreed, they produce healthy but infertile offspring. These two groups are classified as distinct species according to

Accepted Answer

A)  the taxonomic species concept. 
B)  the evolutionary species concept. 
C)  the recognition species concept. 
D)  the biological species concept. 
E)  All of the species concepts are correct. 
A)  the taxonomic species concept. 
B)  the evolutionary species concept. 
C)  the recognition species concept. 
D)  the biological species concept. 
E)  All of the species concepts are correct.

Question 12

Which of the following is NOT a barrier that can prevent gene flow between populations?

Accepted Answer

A)  Temporal isolation 
B)  Spatial isolation 
C)  Physical isolation 
D)  Fractional isolation 
E)  Ecological isolation 
A)  Temporal isolation 
B)  Spatial isolation 
C)  Physical isolation 
D)  Fractional isolation 
E)  Ecological isolation

Question 13

The MN blood group in humans is controlled by two codominant alleles, LM and LN. Individuals with blood types M and N are homozygous, while heterozygous individuals are blood type MN. If, in an isolated population, the probability of carrying the LM allele is 0.3, what is the probability of carrying the LN allele?

Accepted Answer

A)  0.1 
B)  0.3 
C)  0.5 
D)  0.7 
E)  0.9 
A)  0.1 
B)  0.3 
C)  0.5 
D)  0.7 
E)  0.9

Question 14

Which of the following traits would be inherited by the organism's offspring?

Accepted Answer

A)  A kangaroo is born with more acute hearing than others in its cohort. 
B)  A fish embryo exposed to a harmful drug early in development grows into an adult with stunted fins. 
C)  A tree has a twisted growth habit in a high-wind area. 
D)  An adult horse exposed to radiation has a mutation causing a pigmentation spot on its flank. 
E)  A flower growing in rich soil produces many brightly coloured flowers. 
A)  A kangaroo is born with more acute hearing than others in its cohort. 
B)  A fish embryo exposed to a harmful drug early in development grows into an adult with stunted fins. 
C)  A tree has a twisted growth habit in a high-wind area. 
D)  An adult horse exposed to radiation has a mutation causing a pigmentation spot on its flank. 
E)  A flower growing in rich soil produces many brightly coloured flowers.

Question 15

Speciation involves all of the following, EXCEPT

Accepted Answer

A)  physical isolation. 
B)  ecological isolation. 
C)  temporal isolation. 
D)  geographical isolation. 
E)  polyploidy. 
A)  physical isolation. 
B)  ecological isolation. 
C)  temporal isolation. 
D)  geographical isolation. 
E)  polyploidy.

Question 16

Evolutionary trees constructed from gene sequences

Accepted Answer

A)  may allow us to determine the evolutionary history of species. 
B)  reveal information about the history of the gene itself. 
C)  can be used in conjunction with trees constructed from morphological characters. 
D)  demonstrate the relatedness of species. 
E)  All of the answers are correct. 
A)  may allow us to determine the evolutionary history of species. 
B)  reveal information about the history of the gene itself. 
C)  can be used in conjunction with trees constructed from morphological characters. 
D)  demonstrate the relatedness of species. 
E)  All of the answers are correct.

Question 17

Sympatric speciation

Accepted Answer

A)  is defined as the formation of polyploids. 
B)  involves geographic barriers to migration and gene flow. 
C)  occurs without geographic separation of populations. 
D)  results from secondary contact between populations. 
E)  describes the interaction between populations which exist in adjacent areas. 
A)  is defined as the formation of polyploids. 
B)  involves geographic barriers to migration and gene flow. 
C)  occurs without geographic separation of populations. 
D)  results from secondary contact between populations. 
E)  describes the interaction between populations which exist in adjacent areas.

Question 18

Mutations that have no effect on fitness

Accepted Answer

A)  are advantageous. 
B)  will vary in frequency due to genetic drift. 
C)  usually become established in the population. 
D)  are always in the third position of a codon. 
E)  are selected for by environmental conditions. 
A)  are advantageous. 
B)  will vary in frequency due to genetic drift. 
C)  usually become established in the population. 
D)  are always in the third position of a codon. 
E)  are selected for by environmental conditions.

Question 19

Postzygotic reproductive isolating mechanisms act

Accepted Answer

A)  before fertilisation. 
B)  before mating. 
C)  after mating but before fertilisation. 
D)  to produce non-viable zygotes. 
E)  after fertilisation. 
A)  before fertilisation. 
B)  before mating. 
C)  after mating but before fertilisation. 
D)  to produce non-viable zygotes. 
E)  after fertilisation.

Question 20

A population in Hardy-Weinberg equilibrium has the possible genotypes AA, Aa and aa. If the frequency of the A allele is 50 per cent in one generation, then the frequency of aa homozygotes in the next generation will be

Accepted Answer

A)  0.25. 
B)  0.33 
C)  0.5. 
D)  0.75. 
E)  1. 
A)  0.25. 
B)  0.33 
C)  0.5. 
D)  0.75. 
E)  1.

Exam 34: Mechanisms of Evolution

A individual has a spontaneous single nucleotide polymorphism within an intron region of a transcriptional regulator. Such a mutation is likely to

A river takes a new path and divides a species of skinks into two isolated populations. Climate changes gradually cause the river to dry up, bringing the two populations together again, but when individuals of the two populations mate, the resulting hybrids are sterile. This is an example of

Most genetic variation in populations results from

Adaptation

Gene duplications

Sickle cell anaemia is a debilitating disease caused by a mutation in a haemoglobin gene. Homozygotes for this allele have decreased fitness and suffer haemolytic anaemia. However, the allele occurs at high frequencies in some populations because

A seabird living on a small island is born with a mutation that gives it a coloured patch on the top of its head. The mutation is dominant and appears to be neutral. Over the next twenty generations, the frequency of the 'head patch' allele should

Two genes are shown to be close together on the same chromosome. In regard to recombination, these two genes would be

Which of the following is NOT a barrier that can prevent gene flow between populations?

Which of the following traits would be inherited by the organism's offspring?

Speciation involves all of the following, EXCEPT

Evolutionary trees constructed from gene sequences

Sympatric speciation

Mutations that have no effect on fitness

Postzygotic reproductive isolating mechanisms act

A population in Hardy-Weinberg equilibrium has the possible genotypes AA, Aa and aa. If the frequency of the A allele is 50 per cent in one generation, then the frequency of aa homozygotes in the next generation will be

Nature of Molecules

Biomolecules

The Chemistry of Life

Functioning Cells

Movement Across Membranes

Harvesting Energy

Cells, Tissues and Signals

Cell Division

Inheritance

Genes, Chromosomes and Dna

The Genetic Code

Gene Expression

Genomes, Mutation and Cancer

Viruses

Genetic Engineering and Biotechnology

Reproduction, Growth and Development of Flowering Plants

Structure of Plants

Plant Nutrition, Transport and Adaptation to Stress

Plant Hormones and Growth Responses

Animal Reproduction

Animal Development

Homeostasis: Water, Solutes and Excretion

Gas Exchange in Animals

Circulation

Metabolism, Temperature Regulation and Environmental Stress

Animal and Human Nutrition

Innate Defences and the Immune System

Hormonal Control in Animals

Nervous Systems

Animal Movement

Animal Behaviour

Evolving Life

Evolving Earth

Bacteria

The Protists

Plants

Fungi

Simple Animals: Sponges to Flatworms

Annelids, Molluscs, Nematodes and Arthropods

Echinoderms and Chordates

Australian Biota

Population Ecology

Living in Communities

Ecosystems

Human Impacts

Filters