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HOW to DRAW….. PowerPoint Presentation
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HOW to DRAW…..

HOW to DRAW…..

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HOW to DRAW…..

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  1. HOW to DRAW….. a beetle in 20 steps

  2. what you’ll need: • piece of paper or sketch book • sharp pencil and a good eraser • straight edge ruler note: some teachers may wish to demonstrate on a large sketchpad, a black/white board or with overhead transparencies.

  3. Step 1. Have students place papervertically. In the center of the page,draw a small equilateral triangle, pointing down (towards bottom of page). note: teachers can also use this to discuss ‘triangles’. Also, although it doesn’t yet look like a beetle:this triangle will become your beetle’s scutellum, which is part of the meso-thorax 8 x 11.5 piece of paper

  4. Step 2. Draw four straight lines from your triangle as shown below.Two short lines, and two long lines.Notice that TWO lines originate ata right angle from the upper right corner of the triangle note: teachers can also use this to discuss RIGHT ANGLES

  5. Step 3. Connect the left short line to the downward facing line with a long curved line. Do the same with the upper and right hand lines. these two shapes will become your beetle’s elytra

  6. Step 4. add one more long curve that originates to the right of the triangle, and extends down, curving towards the bottom-most point. this line defines a region that will become 2 parts in your finished drawing: (1) the metathorax and (2) the abdomen

  7. ADDED mathematical subject: variables x x x x teachers may wish to use variables to illustratethe similarities in some of the lengths.

  8. Step 4. draw a longer line, parallel to the long horizontal line drawn in step 2. At the end, draw a curved line down and back towards the center of the page. The shape drawn should look like the front of a canoe or a blade. this region will define the beetle’s flight or hind wing, also called the metathoracic wing.

  9. Step 5. draw 5 parallel lines and little circles above each one as shown below. these lines define the abdominal segments and the circles are the spiracles

  10. Step 6. draw a line, parallel to the top of the original triangle (step 1) that extends left almost (but not quite) to the left hand edge of the drawing. Then connect it to the upper left corner with a curved line the region defined by these two lines will be the prothorax

  11. Step 7. The next few steps deal with the beetle’s HEAD. To begin, draw three horizontal parallel lines above your drawing. The distance above should be approximately equal to one side of the original triangle and they should be positioned directly over the triangle from step 1.

  12. Step 8. add two small ovals on each side of the lower line drawn in step 7. The ovals should connect this line to the line drawn in step 6. these two shapes will become your beetle’s compound eyes

  13. Step 9. connect the parallel lines drawn in step 7 these two trapezoids will become your beetle’s clypeus and labrum

  14. Step 10 (halfway there). Add two zig-zag lines up from the top of the beetle.

  15. Step 11. Connect the zig zags to the lines drawn in step 9 with two curved lines. these two shapes will become your beetle’s mandibles

  16. Step 12. we’re going to focus in on the head and add a set of antennae and some palpi start by adding two rectangles that emerge from the head above the compound eyes. Add a smaller square or rectangle on top of each these will be the first two segments of the antennae.The larger segment is the scape and the smaller one is the pedicel

  17. Step 12. we’re going to focus in on the head and add a set of antennae start by adding two rectangles that emerge from the head above the compound eyes. Add a smaller square or rectangle on top of each these will be the first two segments of the antennae.The larger segment is the scape and the smaller one is the pedicel

  18. Step 13. beetle antennae are very diverse – but most have 8-30 more segments on each antennae. The simplest one to draw is the filiform antenna. add a ‘tail’ like shape to the end of each pedicel and then subdivide this with lots of lines to make the segments. repeat on other side. this entire part of the antennae is called the flagellum

  19. Step 14. palpi. Under the mandible of most insects (including beetles) is a small pair of what look like little antennae called maxillary palpi to add maxillary palpi- draw three contiguous ovals between the scape and the mandible. this entire part of the antennae is called the flagellum

  20. Step 15. legs. All insect legs have 6 legs, each with 6 parts. But only 5 parts are usually visible from above. We’re only going to illustrate the LEFT legs in this drawing. each of these shapes is the femur of one leg. The plural of femur isn’t “femurs”…it’s: femora draw three rectangular shapes on the side of your beetle.

  21. Step 16. now add a longer rectangular to each of these each of these is the tibia of one leg.

  22. Step 17. on each tibia, we add 5 rectangles or ovals, that look like beads on a string. each of these strings is a tarsus and each segment (bead) is a tarsomere

  23. Step 18. on each tarsus, add two little claws each claw is called a pretarsus or tarsal claw

  24. Step 19. add parallel lines to elytra grooves on the elytra are called striae

  25. Step 20. (optional) add remaining legs.

  26. YOU’RE DONE!!!! CONGRATULATIONS YOU HAVE DRAWN A BEETLE!!!!

  27. step 1. draw a light vertical line about 1” from the RIGHT edge of you piece of paper. we’re going to erase this line in the next step

  28. add 13 horizontal lines beginning about 1” from top and about ½” apart. NOW erase the line from the preceding step lightly letter these ‘A’through ‘M’ (we’ll erase these letters at the end..so do them lightly). A B C D E F G H I J K L M

  29. draw a line from the outstretched elytron to line F and write ‘Elytron’ A B C D E F G H I J K L M Elytron

  30. place the word ‘Wing’ inside the outstretched wing A B C D E F G H I J K L M Elytron Wing

  31. draw a line from one eye to line C and write ‘compound eye’ A B C D E F G H I J K L M Compound Eye Elytron Wing

  32. draw a line from the right mandible to line A and write ‘mandible’ A B C D E F G H I J K L M Mandible Compound Eye Elytron Wing

  33. draw a line from the right mandible to line A and write ‘mandible’ A B C D E F G H I J K L M Mandible Maxillary palpus Compound Eye Elytron Wing

  34. draw a line from the right mandible to line A and write ‘mandible’ A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Elytron Wing

  35. Eitherwrite the word ‘Pronotum’ inside the region to the left of the elytron OR draw a line to line D and write the word ‘Pronotum’ there. A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum Pronotum Elytron Wing

  36. draw a line from the central triangle to line E, and write ‘Scutellum’ A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum Scutellum Elytron Wing

  37. Metanotum will go in line G with a line drawn to the region directly right of the central triangle A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum Scutellum Elytron Wing Metanotum

  38. Metanotum will go in line G with a line drawn to the region directly right of the central triangle A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum Scutellum Elytron Wing Metanotum Abdominalsegments

  39. Metanotum will go in line G with a line drawn to the region directly right of the central triangle A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum Scutellum Elytron Wing Metanotum Spiracle Abdominalsegments

  40. The parts of the leg can all be done at once with a line to the top segment going to J, the next to K, the claws at the bottom to M and then a bracket for the little segments leading to line L these are labeled: Femur (J), Tibia (K), Tarsus (L) & Tarsal Claw (M) A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum Scutellum Elytron Wing Metanotum Spiracle Abdominalsegments FemurTibiaTarsusTarsal Claw

  41. Body regions are denoted by large square brackets as shown here. A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum HEAD Scutellum Elytron THORAX Wing Metanotum Spiracle ABDOMEN Abdominalsegments FemurTibiaTarsusTarsal Claw

  42. last step is to erase the letters we put on the lines to the right…and the lines themselves if you like you now have a scientific illustration of generalized beetle anatomy!!! Mandible Maxillary palpus Antenna Compound Eye Pronotum HEAD Scutellum Elytron THORAX Wing Metanotum Spiracle ABDOMEN Abdominalsegments FemurTibiaTarsusTarsal Claw

  43. A legend can be added to to finish it off Mandible Maxillary palpus Antenna Compound Eye Pronotum HEAD Scutellum Elytron THORAX Wing Metanotum Spiracle ABDOMEN Abdominalsegments FemurTibiaTarsusTarsal Claw Scientific Illustration Beetle Anatomy (dorsal view) Student NameSeptember, 2009