Kenneth Angielczyk, MacArthur Curator the Paleomammalogy and also Section Head, Negaunee Integrative study Ctr

A concept is a closely thought-out explanation for observations of the natural civilization that has been constructed using the scientific method, and which brings together numerous facts and hypotheses.

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In a previous blog post, ns talked around the an interpretation of “fact” in a clinical context, and also discussed exactly how facts differ from hypotheses and also theories. The last two terms also are fine worth looking in ~ in an ext detail because they space used in different way by scientists and the general public, i m sorry can reason confusion once scientists talk around their work.

In common parlance, concept is frequently used to describe something the is rather speculative. Because of this, it periodically takes ~ above a an adverse tone (for example, once creationists express to development as “just a theory”). This an interpretation strongly contrasts v the meaning of concept as the is supplied in science: a theory is a closely thought-out explanation for observations of the natural world that has been created using the scientific method, and also which bring together countless facts and also hypotheses. The term hypothesis is good to define in this conversation as well: a theory is one idea the we deserve to test with further scientific observations.


With these meanings in mind, a simplified version of the scientific procedure would be as follows. A scientist makes an observation of a herbal phenomenon. She then devises a hypothesis about the explanation that the phenomenon, and also she designs an experiment and/or collects additional data to check the hypothesis. If the test falsifies the hypothesis (i.e., mirrors that it is incorrect), she will have to construct a new hypothesis and test that. If the hypothesis is corroborated (i.e., no falsified) by the test, the scientist will retain it. If the survives extr scrutiny, she might eventually shot to combine it into a bigger theory that helps to define her observed phenomenon and relate that to various other phenomena.

That"s all fairly abstract, for this reason let"s look in ~ a concrete example involving some current research i undertook through a group of collaborators. The concept of evolution states that the process of natural an option should work-related to optimize the role of one organism"s parts if the alters increase the opportunities of the biology successfully creating offspring and the changes are heritable (i.e., have the right to be passed under from generation to generation).

Consider a turtle"s shell. Turtles with stronger shells will certainly be an ext likely to survive encounters v predators, and also thus will certainly be much more likely come successfully develop offspring. End time, natural choice will weed the end turtles through weaker shells (i.e., those individuals will develop fewer offspring), causing a types that has fairly strong shells.


But what happens once there room multiple selective pressure at work? We might hypothesize that turtles that spend most of their time in water challenge a trade-off in between having a strong shell and also one that is streamlined (making them more efficient swimmers), whereas streamlining would certainly be less vital to tortoise on land, allowing them come evolve more powerful shells also if they aren’t very streamlined.

My collaborators and I experiment this theory in the adhering to way. First, we digitized the shell shapes of a number of turtle species, few of which are aquatic and others of i m sorry spend most of your time ~ above land. Us then provided an engineering method called finite element evaluation (or FEA) to study the toughness of the in different ways shaped shells as soon as they were based on a crushing force, similar to a predator"s bite. To measure up how centralized the shells are, us measured your cross-sectional areas, with the idea the a domed shell with a tall cross-section is less streamlined than a flattened shell with a low cross-section. Finally, we offered a mathematical model of natural choice to estimate exactly how much the a trade-off between strength and also streamlining each species was compelled to make, given the observed shape and strength that its shell.


Our outcomes corroborated our hypothesis that aquatic turtles are compelled to make much more of a trade-off between strength and streamlining 보다 turtles the live ~ above land. In general, the shell shapes of ours aquatic tortoise were more streamlined but weaker than those of our land turtles, and also our mathematical design of natural an option indicated that an option for streamlining to be acting an ext strongly on the aquatic species.

As with any kind of idea in science, our outcomes are open up to more testing. For example, various other researchers might develop a much better model the natural choice that shows that our version was too many simplistic. Or they might collect data from much more turtle types that shows that our outcomes were based upon a false pattern stemming indigenous sampling too couple of species (we considered 47 species in ours dataset, about 14% that living tortoise species). For now, though, our results have the right to be included as a piece of proof that is consistent with the guess of the huge explanatory theory of evolution.

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If girlfriend would choose to learn much more about this research, the scientific document describing the work deserve to be uncovered in the newspaper of Vertebrate Paleontology. You can see few of the turtle specimens that we supplied in this study in The field Museum"s exhibition Specimens: Unlocking the secrets of Life, open through January 7, 2018.