Ethology practice [32 marks] 1a. [2 marks] Male eastern bluebirds (Sialia sialis) display brilliant UV-blue feathers on their heads, backs, wings and tails. The brightness index of the male was calculated; the larger the score, the brighter the blue feathers. A brightness value of 0 indicates normal male brightness, so birds with negative scores are less bright than normal. In an experiment to see the mating behaviour of bluebirds, scientists separated pairs of males and females and then allowed females to choose new partners. The graph shows the relationship between male brightness index and choice of mate by females in eastern bluebirds. [Source: Reprinted from Animal Behaviour, 78, Liu, M., Siefferman, L., Mays, H., Steffen, J.E. and Hill, G.E., A field test of female mate preference for male plumage coloration in eastern bluebirds. pp.879–885. 2009 with permission from Elsevier and The Association for the Study of Animal Behaviour. https://www.sciencedirect.com/journal/animal-behaviour.] Evaluate the hypothesis that females prefer to mate with males whose feathers are a brighter blue. 1b. [3 marks] Explain how natural selection can cause mate selection behaviour patterns to develop in a species such as eastern bluebirds. 1c. [1 mark] Another type of behaviour is altruistic behaviour. Outline an example of altruistic behaviour. Example of altruistic behaviour: - Giving blood to a bat who has not fed incurs a cost to the giver as some of daily diet is lost – not merely co-operation but altruism 2a. [1 mark] Many animals have a unique technique for courting their mate. The male peacocks (Pavo cristatus) spread their brightly-coloured tails to impress the females (peahens). [Source: cocoparisienne/Pixabay] Courtship behaviour leads to mate selection. Describe innate behaviour. - Innate behaviour is an instinctive response that is developmentally fixed – it is independent of environmental context - Innate behaviours have a genetic basis and are hence inherited from parents 2b. [3 marks] Explain the implications of courtship behaviour in natural selection. - The most fittest animals have the best courtship behaviour - Courtship behaviour is innate - Courtship behaviour results in mate selection 2c. [2 marks] Outline operant conditioning, giving an example. - When animals learn to associate a reward with a certain type of behaviour and an example is animal training 3a. [2 marks] The performance of mice on a Barnes maze, shown in the photograph, was used to test the effect of cinnamon on learning. Mice were trained for three days to find a compartment in the maze containing food. Their ability to find the compartment was tested by placing the mice at the centre and recording their movement. The mice were divided into two groups according to the route taken: good performers and poor performers. After this all the mice were fed a small amount of cinnamon in their diet for 30 days. They were then trained for three days and retested on the maze. The diagrams show the movements of a typical good performer and a typical poor performer before and after cinnamon was included in their diet. [Source: reprinted by permission from: Springer Natures, Journal of NeuroImmune Pharmacology, Cinnamon Converts Poor Learning Mice to Good Learners: Implications for Memory Improvement, Khushbu K.Modi et al, copyright 2016] Describe how the use of cinnamon changes mouse performance on the Barnes maze. 3b. [3 marks] Scientists demonstrated that cinnamon increased neural plasticity in some parts of mouse brains. Explain how neural plasticity could have affected learning in poor performer mice. 3c. [1 mark] It has been suggested that cinnamon might be of benefit to patients who are recovering from a stroke. Suggest one advantage of adding cinnamon to the diet of a patient who has suffered a stroke. 4a. [2 marks] Distinguish between learned behaviour and innate behaviour. 4b. [3 marks] An investigation was carried out to examine whether honeybees (Apis mellifera) can learn “rules” to deal with complex tasks and then apply them to new situations. To train bees, they were rewarded each time they followed a cue to make a correct turn at the start of a training maze. They were then allowed to find their way through the entire training maze. This was followed by attempts to navigate two unfamiliar mazes (maze 1 and maze 2) to see whether the bees could apply the rules to follow a path through different mazes. Untrained control bees were also put into mazes. Only one bee was tested in each maze at a time. The bees were classified according to how successful they were in making their way through each maze. The results are shown in the bar chart. [Source: reprinted from Neurobiology of Learning and Memory, 72, S.W. Zhang et al, Honeybee Memory: Navigation by Associative Grouping and Recall of Visual Stimuli, 180–201, Copyright 1999, with permission from Elsevier] Evaluate how the data supports the hypothesis that honeybees are able to learn to use cues to find the path through new mazes. 4c. [1 mark] Suggest an advantage of such behaviour. 5a. [1 mark] The shore crab (Carcinus maenas) forages for food in the intertidal zone on rocky seashores. An experiment was carried out to assess predation at specified levels of food abundance. An area of shore was enclosed in a wire cage. All other food was removed from the encaged area except the mussels provided by the investigators. The number of mussels consumed was measured while the crabs foraged at densities of one, two or four crabs per cage. [Source: reprinted from B D Griffen and D G Delaney, Ecology, 88 (12), pages 3012–3021, copyright 2007, with permission, the Ecological Society of America] Suggest a reason for the plateau in the graph when only one crab is present in the cage. 5b. [2 marks] Determine whether foraging by crabs is dependent on number of prey (mussels) or number of predators (crabs). 5c. [2 marks] Outline the role of natural selection in animal behaviour. 6. [3 marks] The drawing shows male and female Emperor birds of paradise (Paradisaea guilielmi ) found in Papua New Guinea. Suggest how the external features and courtship behaviour of these birds of paradise affect reproductive success. Printed for ST GEORGES SCH DUISBURG © International Baccalaureate Organization 2023 International Baccalaureate® - Baccalauréat International® - Bachillerato Internacional®
