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GRADE 11A: Biology 6 UNIT 11AB.6 4 hours Evolution by natural selection About this unit Previous learning Resources This unit is the sixth of eight units on biology for Grade 11 advanced. To meet the expectations of this unit, students should already know that species are clustered into groups. They should know about the hierarchy of classification and the key features of the kingdoms and main phyla of animals and plants The main resources needed for this unit are: The unit is designed to guide your planning and teaching of biology lessons. It provides a link between the standards for science and your lesson plans. The teaching and learning activities should help you to plan the content and pace of lessons. Adapt the ideas to meet your students’ needs. For extension or consolidation activities, look at the scheme of work for Grade 12A and Grade 10A. You can also supplement the activities with appropriate tasks and exercises from your school’s textbooks and other resources. Introduce the unit to students by summarising what they will learn and how this builds on earlier work. Review the unit at the end, drawing out the main learning points, links to other work and real world applications. Expectations By the end of the unit, students understand that predation, disease and competition result in differential survival rates and reproduction, and that organisms with a selective advantage are more likely to survive and pass on genes to the next generation, that natural selection and isolation can lead to new species, and that evolution over a long period of time has given rise to the diversity of living organisms. • overhead projector (OHP), whiteboard • pictures of a variety of organisms • videos of wildlife in an African reserve and on the Galapagos Islands • Internet access Key vocabulary and technical terms Students should understand, use and spell correctly: • evolution by natural selection, speciation • palaeontology Students who progress further know how some organisms are structurally and physiologically adapted to their environment and distinguish between acclimatisation and adaptation. They understand ecological colonisation and succession. 249 | Qatar science scheme of work | Grade 11 advanced | Unit 11AB.6 | Biology 6 © Education Institute 2005 Objectives for the unit 4 hours SUPPORTING STANDARDS the survival and reproduction of the strongest individuals and that this natural selection allows the inheritance of their characteristics. Natural selection of individuals 10A.14.1 Understand the term species, know Natural selection, speciation and diversity Adaptation to environment 11A15.2 Know that natural selection and breeding isolation can lead to speciation. that species can be placed in groups with shared features, and that the groupings of kingdom, phylum, class, order, family, genus and species form a hierarchy of classification. 10A.14.2 Know the distinguishing features of 1 hour CORE STANDARDS Grade11 standards 11A.15.1 Know that predation, disease and competition within a population result in 1 hour 2 hours Unit 11AB.6 the five kingdoms: Prokaryotae, Fungi, Protoctista, Plantae and Animalia. 10A.14.3 Use knowledge of the key features of the major phyla of animals and plants to recognise a typical member. EXTENSION STANDARDS 12A.13.1 Explain examples of structural and physiological adaptations of animals to their environment. 12A.13.2 Distinguish between the permanent adaptation of an organism to its normal environment and the temporary acclimatisation of a visitor. 11A.15.3 Explain how natural selection and evolution over a long period of time have resulted in a great diversity of forms among living organisms. 11A.15.4 Give examples and explanations of how organisms are adapted to survive in particular environmental conditions. 250 | Qatar science scheme of work | Grade 11 advanced | Unit 11AB.6 | Biology 6 12A.14.3 Describe the progression of the development of an ecological community from primary colonisation to climax community. © Education Institute 2005 Activities Unit 11AB.6 Objectives Possible teaching activities 1 hour Introduce natural selection by using familiar examples so that students become immediately involved. Animals are the most easily observed and familiar organisms for most students. Ask them, for example: Natural selection of individuals Know that predation, disease and competition within a population result in the survival and reproduction of the strongest individuals and that this natural selection allows the inheritance of their characteristics. Notes School resources • Have you seen a duck nesting in the local park or pond? • How many young did it produce? • What has happened to those young birds? • Why aren’t we overrun with ducks when they reproduce so many young? Alternatively, show a video of predators and prey in an African wildlife reserve. Discuss the role of predators. Make sure students appreciate that predation is essential in maintaining stable populations of the strongest individuals. Reinforce previous knowledge on animal populations, including predator–prey interactions as well as inter- and intra-specific competition for food and space, by using further examples. Ask students how territorial behaviour helps natural selection. The territorial behaviour of animals, for example, deprives the weaker individuals of food and a suitable breeding location, leading to the loss of these genes from the gene pool. Ask students how disease helps natural selection. Tell them about rabbits and myxomatosis. Explain that 1% of the rabbits survived the disease – these were the resistant rabbits and so they became the naturally selected individuals for the future generations. Get students to find out about the work of Darwin and Wallace from the library. Discuss their findings in class and then ask them to write a report on the theory of evolution by natural selection. 2 hours Natural selection, speciation and diversity Know that natural selection and breeding isolation can lead to speciation. Explain how natural selection and evolution over a long period of time have resulted in a great diversity of forms among living organisms. Having introduced Darwin and Wallace in the earlier discussion, use this to provide a starting point to discuss how new species have evolved. Show students a video of the Galapagos Islands, including film of the unique fauna found there: the finches (Darwin’s finches), the giant tortoises and the iguanas in particular. Use these animals to discuss isolation and speciation. Involve students in a discussion of the unique fauna of the Australian continent, which is another excellent example of isolation and speciation. Make sure the discussion includes the predominance of marsupials and the ecological niches they occupy, and compare these with the placental mammals of Asia or Africa. Hold a class debate in which teams of students put forward scientific evidence for and against the theory of evolution by natural selection. Ensure evidence is presented from scientific observations in: geographical distribution of organisms, comparative anatomy, molecular biology, embryology, taxonomy and palaeontology. Students could select or be allocated a specific piece of evidence to research to bring to the debate. 251 | Qatar science scheme of work | Grade 11 advanced | Unit 11AB.6 | Biology 6 © Education Institute 2005 Objectives Possible teaching activities Notes School resources Get students to compare the Darwin–Wallace theory of natural selection with the theory of Lamarck, who proposed that evolutionary change could be achieved by the transmission of acquired characteristics. This could be part of the debate on evolution. Emphasise the mass of evidence in support of the Darwin–Wallace theory and the lack of support for Lamarck’s ideas. The overwhelming direct evidence of natural selection comes from the fossil records, which provide a trace of evolutionary pathways over millions of years. Show students examples of fossils and/or visit a museum to see exhibits of fossils. 1 hour Adaptation to environment Give examples and explanations of how organisms are adapted to survive in particular environmental conditions. Provide specimens of fossils. Visit opportunity: Visit a natural history museum. Select some examples of animals from a variety of environments and ask students to write a list of the ways the animal is adapted to its particular environment (e.g. polar bears or seals in the Arctic, whales or sharks in the oceans, swifts or swallows in the air of many continents, zebras or lions in the tropical savannah). Similarly, select some plants from a variety of environments and carry out the same exercise (e.g. aquatic plants such as water lilies, marginal plants such as reeds, marram grass (Ammophilia arenaria) of sand dunes, succulents and cacti of deserts). Present students with pictures of specific organisms and ask them to match these to descriptions of their adaptations for living in their natural habitat. 252 | Qatar science scheme of work | Grade 11 advanced | Unit 11AB.6 | Biology 6 Provide a set of pictures of a variety of specific organisms and a separate set of descriptions of their adaptations. © Education Institute 2005 Assessment Examples of assessment tasks and questions Assessment Set up activities that allow students to demonstrate what they have learned in this unit. The activities can be provided informally or formally during and at the end of the unit, or for homework. They can be selected from the teaching activities or can be new experiences. Choose tasks and questions from the examples to incorporate in the activities. Unit 11AB.6 Notes School resources How does the innate territorial behaviour of a bird help to ensure the survival of the species? Suggest a possible way the unique fauna of Australia may have arisen. Give alternative explanations that might have been given by Lamarck and Darwin to explain the giraffe’s long neck. Explain the adaptations shown by the crocodile that have enabled this animal to survive as a species for many millions of years. 253 | Qatar science scheme of work | Grade 11 advanced | Unit 11AB.6 | Biology 6 © Education Institute 2005 254 | Qatar science scheme of work | Grade 11 advanced | Unit 11AB.6 | Biology 6 © Education Institute 2005