Reply To: Photomicrographs for Vol 2, B-14
Thank you for your question, Amy. Sorry to be so long in getting to it.
To start, please don’t make this more complex that it is. The key point of the lesson is to have kids observe that whatever biological tissue we look at, we find that it is comprised small units we call cells. Cells are too small to be seen with the naked eye. The images they are going to examine are made with aid a microscope.
Start with plant tissues where cells are most conspicuous. Google in turn:
Plant leaf cellular anatomy images
Plant root cellular anatomy images
Plant stem cellular anatomy images
Ignore all technical terminology; species makes no difference at all. With each sort of image, draw your kids to focus on the individual units, cells. Have them follow/trace the outlines of cells and model how they are actually three-dimensional structures. They may be shaped like boxes, sausages, pancakes, or otherwise, but whatever their shape(s), they go together to make the particular part of the whole.
You may go on to observe the cellular structure of animal tissues in the same manner. Google in turn:
Skin cellular anatomy images
Muscle cellular anatomy images
________ (insert tissue/organ as your kids desire) cellular anatomy images
You might insert the discovery that all biological tissues are comprised of cells is one of the most profound breakthroughs in the history of biology. That discovery had to wait for the invention of the microscope.
The second part of the lesson.
After the discovery that every biological tissue examined is comprised of cells, the next question was: Where do those cells come from. Untold research and observation has revealed that only origin of a cell is from a pre-existing cell via a process of cell division. The key point is this. All growth and reproduction of biological organisms hinges on the division of one or more pre-existing cells. Following their formation via division, a cell may go on to grow and take on the size, shape, and function of the tissue in which it resides. Have kids observe a time laps video of cell division. You can ignore all technical terminology. The key point at this stage is that the origin of every cell in an organism is from another pre-existing cell.
You and you kids undoubtedly have further questions. Please do not hesitate to post them. I will try to respond in a more timely manner.