Themes in Biology – Science as a Process

2010/04/26
By Sean

Science is a process which encompasses many methods in order to reach a final conclusion. An inference is defined as the reasoning involved in drawing a conclusion or making a logical judgment on the basis of circumstantial evidence and prior conclusions. Inference is a key part of the process of science. Much of the science we know is based on inference instead of actual observation. No person for example, has seen the inside of an atom. But, through inference and other methods of scientific research, we know what the inside of an atom looks like and what the atom is made of. Testing and observing are key parts of science as a process. Scientific ideas and conclusions are evaluated by studying and observing the different tests used to in order to come to that certain conclusion. These tests can be anything from a controlled lab experiment to observations of stars through a telescope. Hypothesizing is another key part to science as a process. Every experiment starts with the scientist hypothesizing the outcome of the experiment. This hypothesis is then proven correct or incorrect after the results of the experiment are carefully analyzed. Lastly, peer review is very necessary in science. After an experiment or observation is conducted, other scientists will review the experiment in order to learn from it and to make sure it was conducted and analyzed correctly.

Photo by cstmweb

In a sequence of experiments from 1909 to 1911, Ernest Rutherford discovered that the majority of an atoms weight was concentrated in the center called the nucleus. He discovered this by completing and analyzing a gold foil experiment. Rutherford fired alpha particles, relatively massless particles consisting of two protons and two neutrons, at a thin sheet of gold foil. Rutherford wanted to measure how much the alpha particles were deflected because the alpha particles have a positive charge and the electrons have a negative charge. The electrons were expected to slightly alter the trajectory of the fired alpha particles. Contrary to Rutherford’s hypothesis, the alpha particles were hardly deflected. After analyzing the experiment, Rutherford concluded that the mass of the atom was not evenly distributed as previously thought. The mass of the atom, in fact, was highest in the center of the atom called the nucleus. Rutherford’s hypothesis for this experiment was disproved, a key part of Science as a process. It is acceptable in science to hypothesize incorrectly as long as you can explain the correct outcome of the experiment.

Tangerine fruit stalk; Photo by Tatcher a Hainu

 In 1838, Theodor Schwann and Matthias Schleiden were sitting together speaking about their study of cells. Schleiden described plant cells as having a nucleus in the center. This directly correlated with Schwann’s observation of animal cells. The two immediately looked at each others slides and came up with a cell theory which stated:

1) The cell is the unit of structure, physiology, and organization in living things.   

2) The cell retains a dual existence as a distinct entity and a building block in the construction of organisms.

3) Cells form by free-cell formation, similar to the formation of crystals (spontaneous generation).

In this case, Schwann and Schleiden used many different processes of Science. They Experimented, inferred, and collaborated in order to come to their conclusion.

Louis Pasteur; Photo by Euclid vanderKroew

Louis Pasteur, a French scientist, disproved the theory of spontaneous generation. This theory stated that living organisms could be made from non-living matter. In order to disprove this, Pasteur boiled meat broth into a flask and shaped the flask into an S shape. Air could enter the S shaped flask, but small microorganisms could not. After many days, as expected by Pasteur, no organisms grew in the broth. In the broth that Pasteur left in a regular open flask, however, organisms grew. This proved that organisms couldn’t just appear. Pasteur hypothesized correctly and accurately conducted an experiment to prove his hypothesis. This was one of the landmark experiments at the time, disproving a common theory.

Photo by Roberto F

Karl von Frisch, an Austrian ethologist, studied honeybees and showed that they use dance to communicate food locations to other bees. Von Frisch noticed that when one honeybee found food, others appeared around the food. He then studied the bee’s movements when it found the food. He observed two different movements or dances. A round dance, which tells other bees to search for food close to the hive and a waggle dance which told other bees the direction and distance to fly toward the food. This study on a population of honeybees helped scientists further understand the movement and food searching methods of the bees. Von Frisch mainly used the scientific process of observation and analysis to reach his conclusions on honeybee dances.

Photo by Storm Crypt

Recently, Harvard University has conducted studies on invading, nonnative plant species, especially those in Massachusetts. The Alliaria petiolata, a common invader in Massachusetts’s forests. This plant threatens other local plants such as sugar maple and breech in the forest. They also studied that the Alliaria petiolata spreads in low light areas. The study of the population of plants in Massachusetts forests help Harvard scientists figure out how to get the nonnative species out and how to help the native plants survive. These scientists observed the plants for hours in order to come up with a hypothesis on what the invading species is doing and a way to help the native species survive.

Photo by KTVee

In 1988 James Lovelock published a book speaking about his Gaia hypothesis. This hypothesizes that all living things have a regulatory effect on the earth’s environment that promotes life. Lovelock came upon this hypothesis while looking at the atmosphere of Mars in its equilibrium. He analyzed that the earth’s atmosphere was never in equilibrium. This highly controversial hypothesis has not been proven. Most scientific discoveries start out as unproven hypothesis. Scientists then conduct experiments to prove or disprove hypothesis and eventually come to a final conclusion.

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