TAS Requirements for Biological drawings

1. TAS Requirements for Biological drawings

2. According to TAS, we can identify the following criteria for assessing biological drawings of students: 1. Accuracy : resemblance to the specimen correct shape and proportion 2. Smooth and clear lines 3. Correct labels or annotations 4. Title, plan of view and magnification 5. Large, overall neatness including the arrangement of labels and label lines

3. (1) The biological drawing technique (A) Draw with sharp, clear and closed lines (B) Shaped with dots (C) Congruence with the specimen (D) index lines without crossing (2) AnnotationsStudents are required to give notes on two structures.Each structure is provided with 1 mark. TAS AREA A2 : This assesses the quality of biological drawings. The criteria is as follow.

4. High power magnification drawings Low power magnification drawings Whole mount specimen drawings The following drawings

5. Orientation • Apart from naming the structures of your drawing correctly, you should describe how the section of the specimen is cut: • The followings are some common terms used to describe sections:

6. 1. Transverse section (T.S.) : at right angles to the long axis of a structure such as a stem; also known ascross section (X.S.) • 2. Longitudinal section (L.S.): along the long axis of a structure such as a stem • 3. Vertical section (V.S.): at right angles to the surface of a structure such as the skin

7. 4. Whole mount (w.m.): e.g. onion epidermis • 5. Teased, macerated, smear, etc.

8. Orientation of sections

9. Title • Always give a title; • You can use the words of the question to phrase your title; NOT like this : T.S. of a root Like this : T.S. of specimen A • Include plan of view and magnification

10. Write the title below the drawing and rather close to it; • Don’t place the title at too great a distance from the drawing or in an ambiguous position such as mid-way between 2 drawings; O.K.? Structures of two guard cell Structures of two guard cell

11. Low power and high power drawings

12. Low power drawing: • Low power magnification means the use of the 10X or lower objective lens and the total magnification power not beyond 100X. • Show the tissue layout / draw the whole or a representative part of the section to show the relative position of different types of tissues;

13. Do not attempt to draw individual cells in a low power drawing; • Low power drawing does not mean a drawing showing the features as seen under a low power magnification of themicroscope, eg. 5x10 !

15. High power drawing: • High power magnification means the use of the 40X or 60X objective lens and the total magnification power up to 400X to 600X. The purpose of these drawings is to show the cell details. • Adjacent cells should be drawn in their proper positional relationships and proportionate size to one another;

16. For plant cell, the cell wall is usually comparatively thick, a double line should be used to represent the thickness; • If the wall is thin, single line can be used; • If cellular structures such as cytoplasm, nuclei, vacuoles and starch grains are visible under high power, they should also be drawn and labeled

17. The purpose is to show detailed cellular structures of a particular tissues or cell types, it is not necessary and time-consuming to draw a complete section through an organ in high power; • Don’t draw too many cells! Draw their representatives or certain typical cells are usually adequate!

19. Whole specimen means to observe with the naked eyes only.

20. Whole specimen drawing

21. By all means imitate the style of the drawings in certain reference books, if that helps; BUT DO NOT COPY THE DRAWINGS OR MEMORIZE THEM !

22. The End