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Profile of a Scientist Level: S4-7 Emphasis: History of Science
Introduction The study of historical development of scientific ideas provides opportunities for students to understand the nature of science, and value the hard work of frontier scientists. By referring to the stories of some famous biologists, students can recapture the life of biologists, the ways they thought, the work they did, and the joy and frustrations they experienced. Through reading the stories of scientists, students will understand that knowledge generated by one generation usually is expanded, modified, or even discarded by the next generation.
Objectives
Skills and Processes
Students should: 1. develop an understanding of the nature of science. 2. develop an understanding of the context in which scientists developed their ideas and the process these ideas went through to be accepted. 3. appreciate the scientific thought and effort of frontier scientists in the pursuit of knowledge.
1. 2. 3. 4. 5.
Collaboration Communication Information handling Scientific thinking Study
Activity 1: How does a scientist look like? •
Divide students into groups of four or five. Ask students to discuss the traits of a scientist, and draw a full body impression of a scientist. Ask students to include a dialogue bubble and in it write what this scientist would be saying. List five traits of the scientist and include a brief explanation.
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Each group will present their drawing in front of the whole class and tell the whole class what is being said.
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Students then vote the three “best” representations of a scientist.
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Students will be asked to brainstorm traits of a scientist starting from what was written on their sheets and to record their results.
Activity 2: The story of Mendel •
Ask students to read the passage about Mendel (refer to student handout) to get a glimpse of the scientist and discuss the following questions: w
Why do you think Mendel chose garden pea in the experiment?
w
Give an account of Mendel’s success.
w
Why was Mendel’s work not recognised between 1866 and 1900?
w
What do you learn from the success of Mendel?
Activity 3: Biography of a scientist •
Divide students into groups of four or five. Ask students to choose a scientist whom they are familiar with or interested in, and make a biography of the scientist.
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Allow them sufficient time to search, organise and analyse information from a variety of sources.
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The biography may include the following: 1.
Who is the scientist?
2.
What did the scientist do?
3.
What was the discovery?
4.
Where and when was the discovery happened?
5.
How was it discovered?
6.
How did the scientist persuade others? Were the ideas accepted by contemporaries? Are they accepted today? Why or why not?
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7.
What elements of the discovery seem most revealing about the nature of science? Why?
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The biography can be presented in a variety of ways such as PowerPoint presentation, role-play, essay, poster or leaflet.
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Each group will have ten minutes to present their biography in the class.
Assessment •
Students will be assessed on their participation in group discussion, group presentation and the ideas in biography presentation. An example of assessment rubrics is suggested as below: Max. Peer Teacher Points Assessment Assessment
Class Discussion
Listening
•
Recognises and responds to others speaking.
5
Non-verbal communication
•
Able to recognise and use appropriate non-verbal communication cues.
5
Participation
•
Shares freely and explain with details.
5
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Supports and leads others in discussion.
•
Works well with others.
•
Assumes a clear role and related responsibilities
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Presents information in a logical, interesting way which audience can follow.
5
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Presentation well planned and coherent.
5
Topic / Content
•
Covers topic completely and in depth.
5
Verbal Communication
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Communicates ideas with enthusiasm.
5
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Uses voice properly.
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Maintains eye contact with audience.
Collaboration
Biography Organisation presentation
Eye contact
5
5
Note: = excellent, 4 = very good, 3 = good, 2 = satisfactory, and 1 = poor.
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References 1. 2. 3. 4. 5.
Mendel Web http://www.netspace.org/MendelWeb/ Pasteur, Louis – Genentech http://www.accessexcellence.org/AB/BC/Louis_Pasteur.html Watson, James D – The People of Genetics http://www.nobel.se/medicine/laureates/1962/watson-bio.html Darwin, Charles – MSN Encarta http://encarta.msn.com/find/Concise.asp?ti=0595D000 Jenner, Edward – Jenner Museum Homepage http://www.jennermuseum.com/
Student Handout – Profile of a Scientist
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The Father of Genetics –Mendel Gregor Mendel (1822-1884), is often known as “the father of genetics”. In those days, people did not know about chromosomes, DNA or genes as we do today. By observing the number and types of characteristics in the offspring plants, Mendel developed the rules of inheritance known as Mendel's laws today. Long before Mendel, many scientists had performed similar experiments on plants, but no one succeeded. They were not able to produce results that had enough accurate and detailed data, nor were they able to explain their results in terms of a mechanism of inheritance. In 1856, Mendel began his eight-year-long experiments. The purpose of his experiments was to study the similarities and differences between parents and offspring. He did this by observing plants reproduced for several generations. He gave a lot of thought to the choice of organism to use and eventually decided on the garden pea, Psium sativum. The pea plants had the following characteristics: they were easy to cultivate and needed only a single season to complete the life cycle; the flower bud was large and could be opened to remove the anthers without damaging the female part of the flower; the reproductive structures were completely enclosed by the petals so that the plant was normally self-pollinating. As Mendel stated, “the value and utility of any experiment are determined by the fitness of the material to the purpose for which it is used”. He cultivated and examined at least 28,000 pea plants, analysed carefully seven pairs of plant characteristics. Besides his famous experiments on peas, Mendel made many crosses between other plant species. He found that the work on hawkweeds was extremely difficult as these plants had very small flowers. He also tried crosses between different varieties of bees but found it very difficult to persuade bees to mate under controlled conditions.
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Mendel published his important work in 1866 in journal, The Proceedings of the Brunn Natural History Society, which was sent to many scientific societies throughout the world. In all cases, the scientists failed to appreciate the importance of his findings. It might due to the fact that scientists at that time had little understanding of hereditary factors transmitted from parent to offspring. It was until 1900, 34 years after his paper was published, that three scientists read his paper, and the significance of Mendel’s work was realised.
About Mendel Questions for discussion 1. Why do you think Mendel chose garden pea in the experiment? 2. Give an account of Mendel’s success. 3. Why was Mendel’s work not recognized between 1866 and 1900? 4. What do you learn from the success of Mendel?
Gregor Mendel was born in a small village in Heinzendorf in 1822. In 1843, he joined an Augustinian monastery in the town of Brunn in Austria (now Brno, in Czechoslovakia). From there he went to the University of Vienna where he spent two years studying natural history and mathematics before returning to the monastery in 1853. Mendel became interested in investigating variation, heredity, and evolution in plants at the monastery’s experimental garden. This formed the basis of Mendel’s scientific investigations on inheritance which he began in the summer of 1856.
Teacher Reference – Profile of a Scientist
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Additional resources for teachers 1. Why was garden pea selected as the experimental organism? Garden pea was selected because: i. The pollen and stigma develop to maturity inside the flower bud and pollination occurs before the flower opens so that natural cross pollination is extremely rare. Different varieties may therefore be grown in the same garden without shielding the flowers. ii. The flower bud is large and can be opened to remove the anthers without damaging the female part of the flower. Artificial cross-pollination can be performed. iii. Many true breeding garden varieties were available with “characters which are constant, and easily recognizable, and when their hybrids are crossed they yield perfectly fertile offspring”. iv. They are easily cultivated and need only a single season to complete their life cycle. (Extracted from Monger, G. (Ed.). (1985). Revised Nuffield advanced biology: Study guides II. pp.67. Essex: Longman.) 2. Give an account of Mendel’s success. Mendel’s success depended largely on his very careful experimental design and on his understanding of the use of statistical ideas. The reasons for Mendel’s success may be taken as a model of how to carry out a scientific investigation. They may be summarised as follow: i. Preliminary investigations were carried out to obtain familiarity with the experimental organism. ii. All experiments were carefully planned so that attention was focused on only one variable at any time, thus simplifying the observation to be made. iii. Meticulous care was taken in carrying out all techniques, thus preventing the introduction of contaminating variables. iv. Accurate records were kept of all the experiments and the results obtained. v. Sufficient data were obtained to have statistical significance. (Extracted from Green, N.P.O., Stout, G.W., Taylor, D.J. & Soper, R. (1998). Biological science 1 & 2 (3rd Ed.). pp.833. Cambridge: Cambridge University Press.) However, it is worth stating that there was an element of luck in Mendel’s choice of experimental organism. The characters chosen by Mendel lacked many of the
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more complex genetic features which were later discovered, such as characteristics controlled by more than one pair of genes.
Reference Green, N.P.O., Stout, G.W., Taylor, D.J. & Soper, R. (1998). Biological science 1 & 2 (3rd Ed.). Cambridge: Cambridge University Press. Monger, G. (Ed.). (1985). Revised Nuffield advanced biology: Study guides II. Essex: Longman.
