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QUESTION 18 The diagram shows the abundance (n) of phenotypic and genotypic variation for the colour trait of a species of butterfly. AA Aa aa n =400 n =500 n= 1000 If these butterflies were placed in an environment with light-coloured trees which option from the table would be the most likely effect on the allelic frequencies? Frequency of allele/genotype A | 2 | AA | I = -- -- --
QUESTION 27 (4 marks) In a freshwater lake in Africa a species of crab and its snail prey species both exhibit specialisations that are unusual for freshwater species. The crabs possess strong claws with characteristics of marine crabs that crush and peel shells and the snail prey have thick strong shells that resist crushing. a) Identify which pattern of evolution this example represents. [1 mark] b) Describe how the two species may have evolved these characteristics. [3 marks]
QUESTION 9 (3 marks) Fossil evidence seems to show that the morphology of the Queensland lung fish has remained relatively unchanged for the past 100 million years. Describe the features of the theory of natural selection to explain how this may have occurred.
QUESTION 10 (3 marks) Researchers measured the adult beak lengths of an entire population of a species of bird and plotted their results on the graph. After many generations the lengths of the adult beaks were again measured. By comparing this new data to the original data the researchers concluded that the average length of beaks had increased as a result of directional selection. nitial distribution / of beak lengths Frequency 0 5 10 15 20 Beak length (mm) a) Describe directional selection. [2 marks]
QUESTION 7 In a long-term study of grasshopper colour in a grassland ecosystem it was found that the most abundant phenotype changed from dark green to straw yellow. dark green straw yellow L7 Population Phenotypic trait (colour) This change in the phenotype is an example of (A) diversifying selection. (B) directional selection. (C) stabilising selection. (D) disruptive selection.
QUESTION 16 A small group of dingoes migrated to a new area and established a population. After several generations the new population showed a different genetic composition from the original population. This is an example of (A) microevolution and gene flow. (B) macroevolution and gene flow. (C) microevolution and genetic drift. (D) macroevolution and genetic drift.
QUESTION 18 Which scenario would create a selection pressure on a given population? (A) change in fur colour (B) change in weather patterns (C) greater resistance to disease (D) 1mproved ability to locate food sources
QUESTION 9 (3 marks) A computer simulation was used to observe genotypic changes in the gene pool of 20 randomly selected rabbits. The simulation was set with these parameters: each rabbit’s coat colour was either black or white » black alleles were dominant; white alleles were recessive « the number of rabbits was constant in each generation and breeding was random throughout the population « an environmental factor was chosen in the simulation to provide selection pressure. The table shows the results of the simulation at the start and after 20 generations. Initial population genotypes Population genotypes after 20 generations BB BB BB BB BB BB BB BB Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb Bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb Contrast the initial allele frequency with the allele frequency after 20 generations to draw a conclusion about the effect of the selection pressure on the rabbit population.
QUESTION 4 The graph shows the effect of a selection pressure on a hypothetical population. Phenotype Key [ ] Before the selection pressure B 20 generations later Number of individuals Which mode of phenotypic selection corresponds with the data? (A) negative (B) disruptive (C) stabilising (D) directional
QUESTION 12 Speciation occurs when (A) the gene pool of an existing species becomes too small to support a viable population. (B) selection pressures cause significant changes to the allele frequencies of a population. (C) genetic drift is no longer occurring within populations. (D) gene flow is no longer occurring between populations.
QUESTION 28 (3 marks) In 1950 the myxoma virus was released into Australian pest rabbit populations to reduce their numbers. The resulting disease myxomatosis initially wiped out 95% of the rabbit population; however it quickly became less effective as a population control measure. This graph shows the frequency of myxomatosis resistance in Australia’s rabbit population from 1949 to 1956. 100 90 S 5 80 o < = 70 5 2 60 & £ 50 o % = 40 (- o > 30 a 3 g 20 [ 10 'v . — | 1949 1950 1951 1952 1953 1954 1955 1956 Year Use evidence from the graph and the principles of natural selection to explain how myxomatosis became ineffective as a population control measure.
QUESTION 11 (8 marks) Allele frequencies were monitored in two large populations of field mice from neighbouring forests over a 10-year period. Results are shown. Forest X [ e s a) Calculate the allele frequencies for forest Y in 2018. Show your working. [2 marks] b) Identify temporal trends in allele frequency for forests X and Y and infer reasons for the observed differences. [6 marks]
QUESTION 20 The graphs below show the trait distribution of a hypothetical population before and after selection. The dotted line indicates the mean of each population. Before selection After selection » 40 ; » 40 3] © . 2 £ s 5 o0 s o0 © ° 2 c c . w 20 w 20 : o o 2 10 2 10 £ g - - < 0 : Z 0 : 0 2 4 6: 8 10 12 14 0 2 4 6 : 8 10 12 14 Phenotype mean Phenotype mean The type of phenotypic selection represented in the graphs is (A) divergent. (B) disruptive. (C) stabilising. (D) directional.
QUESTION 26 (4 marks) Explain microevolutionary change through mutation.
QUESTION 7 The distributions of phenotypes before and after a selection pressure acted on a population are shown. Which graph shows disruptive selection? === Before selection pressure 25 generations later (A) (B) Number of individuals Number of individuals (C) (D) Number of individuals Number of individuals Phenotype
QUESTION 15 Allele frequencies are most likely to stay constant in (A) large populations with low levels of migration. (B) small populations with low levels of migration. (C) large populations with high levels of migration. (D) small populations with high levels of migration.
QUESTION 24 (5 marks) The frequency of a new allele was monitored in a population of insects over an 18-year period. Frequency 0.0 2004 2006 2008 2010 2012 2014 2016 2018 2020 2022 Year a) Infer if the new allele is advantageous or detrimental in this environment. Justify your response using evidence from the graph. [2 marks] b) Explain how mutations can contribute to microevolutionary change in populations [3 marks] that reproduce sexually.
QUESTION 4 (5 marks) The hummingbird hawkmoth (phylum: Arthropoda) is named for its similarity to hummingbirds (phylum: Chordata). The two species have independently developed similar feeding structures which they use to draw nectar from tube-shaped flowers. Both species help plants reproduce by distributing their pollen. a) b) c) Hummingbird hawkmoth Hummingbird Identify the diversification pattern demonstrated by the hummingbird and the hummingbird hawkmoth. [1 mark] Use the principles of natural selection to explain the similarities between the two species. [2 marks] Explain how coevolution of the hummingbird hawkmoth and tube-shaped flowers may have occurred. [2 marks]
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