Chapter 23 Section 2

1. Chapter 23Section 2 Advances in Science And Medicine

2. Cell Theory in Biology • Biological Sciences are sciences that deal with living organisms such as genetics, zoology, botany and biology • Physical Sciences are sciences that deal with the properties of nonliving matter and energy such as chemistry, astronomy, geology and physics • Scientists of the 1800’s were interested in explaining the nature of life as well as the nature of nonliving matter • Early observers, with the help of microscopes, saw what we now know as plant and animal cells. • They noticed that all species cells were different shapes and sizes • But they did not fully understand or draw any general conclusions

3. Cells from an Elodea Plant

4. Dog Kidney Cells Human Brain Cells

5. Continued…. • Finally in 1838, a German botanist and a German biologist clearly expressed cell theory • They stated that all living things are made up of tiny living matter and that all cells divide and multiply causing the organism to grow and mature • In the 1850’s another German scientist expanded on the theory by stating that every new cell must come from some older cell therefore only living matter can produce new living matter • Thus accepting the cell as the basic unit of living matter

6. Lamarck’s Theory of Inheritance • Many scientists believed that plants and animals that live today had developed from common ancestors from long ago • This kind of development through change is called evolution • French biologist Jean-Baptiste Lamarck suggested his theory of inheritance and evolution through adaptation. • Some of Lamarck’s theories were later proved to be wrong and did not become a part of modern biology • But he did influence other scientists such as a British naturalist named Charles Darwin

7. Darwin’s Theory of Evolution • Charles Darwin began his theories with a well-known fact: no two living things are exactly alike not even a parent and its offspring • Darwin combined this fact with the idea that as a result of natural dangers that there will always be more creatures born than can survive • Those that survive will then be the best of the species that can adapt to the environment around them. • They will then produce offspring that possess the characteristics so they can pass them on to future generations • Darwin thought that in this way he could explain the evolution of all forms of life from previous forms • The theory of natural selection was controversial because it stated that human beings developed from animals. • However Darwin felt that his theory of evolution did not challenge the existence of God

8. “There is grandeur in this view of life…having been originally breathed by the Creator into a few forms or into one; and that….from so simple a beginning endless forms most beautiful and most wonderful have been and are being evolved” -Charles Darwin

9. Genetics • An Austrian monk named Gregor Mendel founded genetics, or the study of how characteristics of plants and animals are passed and inherited by their descendants • He began his experiments by crossbreeding tall plants with short plants. To Mendel’s surprise he got tall plants and not medium sized plants • From these experiments Mendel concluded that inborn traits were not blended together. Instead they were all inherited as if they were separate particles • And in some cases a trait could be carried but not expressed • For example: the tall plant could pass the “particles” on to the next generation making one or some of its offspring short

10. The Fight Against Disease • Until the late 1800’s as many as 50% of the population born died within the first five years after birth • Smallpox was one of the deadliest diseases • An English physician named Edward Jenner developed a vaccine for smallpox by the way of exposure to another milder disease called cowpox • Jenner did create a vaccine but he did not know exactly why it worked • Later a French chemist, {Louis Pasteur, identified microorganisms called bacteria • In the 1860’s Pasteur developed the process of heating liquids to kill bacteria and prevent fermentation in a process called pasteurization} • Pasteur also created a vaccine that prevented animals from contracting the germ that causes anthrax. Leading him to the conclusion that when weakened germs enter the body that your body builds up antibodies to fight them

12. Advances in Surgery and Medicine • In the 1840’s medicinal purposes for ether and chloroform were discovered, making longer operations possible • However, people still died from infection afterward • Until a surgeon named {Joseph Lister developed antisepsis, or the use of chemicals to kill germs} • The use of these antiseptics helped to reduce the number of infections after surgery • As people began to realize the sources of diseases such as malaria and the Bubonic Plague they discovered ways of preventing them • During this time Aspirin and Insulin were invented • Alexander Fleming discovered penicillin in 1928 although penicillin drugs were not widely available until the 1940’s

13. The Atom and it’s Structure • Although knowledge of atoms can be traced back to the 1500’s it had not been proven yet • A school teacher named John Dalton created a way to “weigh” atoms in 1803 • Much later in 1869 a Russian chemist, Dmitry Mendeleyev, expanded on this and created the first periodic table • It was expanded upon throughout the years by chemists such as {Pierre and Marie Curie who experimented with radium and plutonium. They found that these elements constantly break down and release energy on their own in a process called radioactivity} • Elements that release energy this way are called radioactive elements • Later evidence was found about electrons and the nucleus, protons and neutrons.

14. Plank and Einstein • Before 1900 scientists believed that energy was a exponential substance, and it could be divided into any number of smaller units • In 1900 Max Planck disproved this with his quantum theory in which he proved that energy could only be released in “definite packages” • {Albert Einstein in studying Planck’s work developed his special theory of relativity which states that no particles of matter can move faster than the speed of light} • Einstein also developed the famous equation, E=mc2. Where he expressed the relationship between energy and mass • Einstein also declared that this is not just a three dimensional universe but a fourth dimension (time) existed. • Einstein called his 4-dimensial system the space-time continuum.

15. Review Questions • This man identified microorganisms called bacteria • Pasteur developed the process of heating liquids to kill bacteria what was it called? • Joseph Lister developed ___________, or the use of chemicals to kill germs • Who found that certain elements constantly break down and release energy on their own in a process called radioactivity • Who developed the theory of relativity which states that no particles of matter can move faster than the speed of light

16. "The release of atom power has changed everything except our way of thinking...the solution to this problem lies in the heart of mankind. If only I had known, I should have become a watchmaker." -Albert Einstein on the bomb