SCI 1030 – Lec 3 slides

Dr Ian Balcom

What is Science?

• Science is a body of knowledge about the natural world.

• The natural world is studied through the use of scientific methods.– observation– Explanation (theories, hypotheses)– Prediction of phenomena through

experimentation

• Science is an objective, logical, and repeatable attempt to understand the principles and forces operating in the natural universe. Science is from the Latin word, scientia, to know

• Theory– A theory is a hypothesis that has been repeatedly tested

with little modification, e.g. The Theory of Evolution. • Law

– is one of the fundamental underlying principles of how the Universe is organized, e.g. The Laws of Thermodynamics, Newton's Law of Gravity. Science uses the word theory differently than it is used in the general population.

• Theory to most people, in general nonscientific use, is an untested idea. Scientists call this a hypothesis.

• Steps in the scientific method commonly include:– Observation: defining the problem you wish to

explain.– Hypothesis: one or more falsifiable explanations for

the observation.– Experimentation: Controlled attempts to test one or

more hypotheses.– Conclusion: was the hypothesis supported or not?

After this step the hypothesis is either modified or rejected, which causes a repeat of the steps above.

• The scientific method includes 2 parts. – The first consists of formulating hypotheses; – the second consists of experimentally testing

them. • What differentiates science from other

knowledge is the second episode: subjecting hypotheses to empirical testing

• Empirical– Founded on experience and observation

• Theoretical– Explanation of phenomena based on theory

Darwin’s finches

Observations

• "It is very remarkable that a nearly perfect gradation of structure in this one group can be traced in the form of the beak, from one exceeding in dimensions that of the largest gros-beak, to another differing but little from that of a warbler"

• Every species is fertile enough that if all offspring survived to reproduce the population would grow (fact).

• Despite periodic fluctuations, populations remain roughly the same size (fact).• Resources such as food are limited and are relatively stable over time (fact).• A struggle for survival ensues (inference).• Individuals in a population vary significantly from one another (fact).• Much of this variation is inheritable (fact).• Individuals less suited to the environment are less likely to survive and less

likely to reproduce; individuals more suited to the environment are more likely to survive and more likely to reproduce and leave their inheritable traits to future generations, which produces the process of natural selection (inference).

• This slowly effected process results in populations changing to adapt to their environments, and ultimately, these variations accumulate over time to form new species (inference).