Chapter 7, Problem 7A

Summary Introduction

To determine : How the development of microscope changed the way scientists studied living organisms.

Introduction : The invention of microscope was a breakthrough in the study of living organisms. It made it possible for scientists to observe and study cells, the basic structure of life.

Answer to Problem 7A

For a long time, scientists had no idea that a living organism is made of millions of cells. Cells are so small that their existence could not be proved without the invention of microscope. The invention of microscope, improvements in the instruments and new technologies led to the development of cell theory and better understanding of cells. The work of many scientists like Robert Hooke and Antony van Leeuwenhoek led to new branches of science and many new discoveries. From simple microscope to compound microscope to electron microscope, the improvement in magnification power has been tremendous. The latest technology, scanning tunneling microscope allows scientists to even see atoms.

Explanation of Solution

Given information:

Development of microscope changed the way scientists studied living organisms.

Scientists initially used lenses to view small organisms to magnify their sizes. In 1600s, Antony van Leeuwenhoek used a single lens microscope to see bacteria for the first time. Later in 17^th century, Robert Hooke invented a simple microscope through which he observed dead cork cells.

By 1800 microscopes were improved which allowed scientists to observe minute details. Robert Brown discovered nucleus. Schleiden examined plant tissue and found that plants consist of cells. Schwann examined cells in animal tissue and Virchow proposed that all cells arise from pre- existing cells. All these led to the discovery of cell theory.

In the 1930s and 1940s, electron microscopes were developed which allowed scientists to magnify an object up to 500,000 times using a beam of electrons. A scanning electron microscope (SEM) and transmission electron microscope (TEM) led scientists to see inside the cell.

The new technologies are continuously improvising the microscope. This has changed the way scientists look at living organisms.

Conclusion

Over the past 65 years, many modifications have been made to the original electron microscope.