Chapter 1

The Characteristics of Life

Organisms have levels of organization and are related to

all other organisms. From atoms, molecules, cells, organs,

organ systems, organisms, populations, community,

ecosystems, and biosphere.

Human Biology Power Point Presentation, Human Biology 156 by Larry M. Frolich, Phd.

Living things grow, develop, reproduce, respond to stimuli, use materials and energy from their surroundings, are homeostatic and evolve.

Humans are no different; we are of the domain Eukarya (one of three domains, Archaea and Bacteria, being the other two). A mammalian vertebrate of the kingdom Anamalia (one of four kingdoms Plantae, Fungi, and Protista, being the other three). We are cousins to the great apes but are different with our more highly developed brain, completely upright stance, language, ability to create and use tools, and our cultural heritage. We humans are also a part of the biosphere and are the only ones that can modify ecosystems on a global scale.

Science as a Process

There are five steps in the scientific method: Making an observation, formulating a hypothesis, doing experiments and making further observations, drawing a conclusion, and then developing a theory based on the previous steps.

One such example is how the cause of ulcers was discovered. Dr. Barry Marshall believed a pathogen was responsible. But to confirm this he used Koch’s postulates and they state: 1) The suspected pathogen (virus or bacterium) must be present in every case of the disease; 2) The pathogen must be isolated from the host and grown in a lab dish; 3) The disease must be reproduced when a pure culture of the pathogen is inoculated into a healthy susceptible host; and 4) The same pathogen must be recovered again from the experimentally infected host.

Dr. Marshall was able to complete the first two requirements but ran into difficulty with the last 2 until he and a colleague actually ingested the bacterium. In his conclusion he felt that his experiment and results were valid. Even though there were only two control subjects.

But the correct way to run a controlled study is to use scientific method: Making an observation, formulating a hypothesis, doing experiments and making further observations, drawing a conclusion, and then developing a theory based on the previous steps. By using a control group in the experiment and observation step. The control group (the larger the control group the better the results) would consist of three groups; 1) would receive a placebo; 2) would receive medicine A and; 3) would receive medicine B. The examiner would then be used to verify the results and it would be best if the examiner had no knowledge of the specifics of the control group to remain impartial. Then base the conclusion on those findings and publish the results in a scientific journal.

While scientific journals are good sources of information the reader is responsible to evaluate other sources for their content, such as the Internet. Because the Internet is not regulated for validity of content.

Making Sense of a Scientific Study

With statistical, anecdotal, and correlation data available for studies, the only one that truly has merit is statistical data. Anecdotal, and correlation data gathering generally do not have large control groups to base their conclusions. Whereas statistical significance can actually give you a standard error to help you measure just how reliable the information gathered as well as the conclusion is. This is easily seen in data presented in bar and/or line graphs because the relationship of the quantities being measured.

Science and Social Responsibility

While the scientists of the world observe, experiment and present their findings, we as the human race must make decisions that affect our biosphere and everything contained within it. We must look forward and weigh the good and evil of technology to advance our knowledge without killing off our planet and us with it!

Sources:

Human Biology 10^th Edition by Sylvia S. Mader

Human Biology Power Point Presentation, Human Biology 156 by Larry M. Frolich, Phd.

Robert Koch, German microbiologist who helped develop, verify, and establish the standard in germ theory as to whether an organism causes a particular disease.