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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 11 (6 marks) The image shows changes in the frequency of a particular gene in a single species of bird leading to a speciation event. These changes have occurred over a period of successive time points (i.e. I IT and III) each separated by approximately 1000 generations. » The letters A B C and D represent separate niches inhabited by the birds. * The arrows depict gene flow between the niches. » The allelic frequency for the gene is shown as f in each niche. 1 111 Draw a conclusion about the type of speciation that has occurred in this population. Explain your reasoning by referring to the information provided in each of the time points.
QUESTION 10 The forelimbs of humans dogs birds and whales have a very similar pattern of bones. Human Bird Whale Not to scale The similarity of these structures is best explained by which pattern of evolution? (A) convergent evolution (B) divergent evolution (C) parallel evolution (D) coevolution
QUESTION 7 (3 marks) Koalas were once widespread in Australia. Due to a variety of factors their population decreased and fragmented into small pockets forcing them to inbreed. They have recently been hit by devastating epidemic diseases. Explain why koalas face an increased extinction risk from disease.
QUESTION 8 (3 marks) Australia has many bird species that have evolved to be largely dependent on mangroves. These species are patchy in their distribution because of: « the island-like distribution of their habitat * exclusion by possible competitors » geographical barriers. Identify and describe the mode of speciation that may have caused diversity in mangrove bird species.
QUESTION 10 Wings in birds bats and pterosaurs are phenotypically similar though they belong to different families and do not have a common ancestor with the trait. While the general morphology is similar the structure and organisation of each wing is different. This is an example of (A) coevolution. (B) parallel evolution. (C) divergent evolution. (D) convergent evolution.
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 8 (3 marks) Over time the South African cheetah population has suffered drastic reduction due to periodic droughts disease and hunting. Currently only small isolated populations of cheetahs exist in the wild. Explain in terms of genetic diversity why cheetah populations are now on the verge of extinction.
QUESTION 6 Which of the following does not cause macroevolution? (A) time (B) mutation (C) extinction (D) speciation
QUESTION 22 Island populations are often isolated and can face an increased risk of extinction because of (A) 1improved reproductive fitness. (B) reduced genetic diversity. (C) decreased genetic drift. (D) unrestricted gene flow.
QUESTION 28 (5 marks) The figure below shows a model of ecological niche occupation by species A—E. : T :_¢§ Species D - ‘© 2 | ® % © . m = 2 Z 2 3 Cool Warm Niche axis 2 — Temperature a) Identify which two species are occupying the same ecological niche. [1 mark] b) Species A and B have a common ancestor. Which diversification pattern would have occurred between species A and species B for them to occupy these niches? [1 mark] The table below shows the frequencies of genotypes and phenotypes for a particular trait in a generation of species E. Genotype (% frequency) Phenotype (% frequency) TT (0) Tt (100) tt (0) Phenotype 2 (0) c) Predict the next generation’s genotype and phenotype frequency. Which type of inheritance pattern is represented for Phenotype 17 Phenotype 1 (100) [3 marks]
QUESTION 4 Populations with reduced genetic diversity face an increased risk of extinction because they (A) have fewer chromosomes. (B) have difficulty finding mates for reproduction. (C) are less likely to adapt to changing environments. (D) contain a larger proportion of heterozygous individuals.
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]
QUESTION 8 (3 marks) Explain how temporal isolation can lead to speciation.
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