INTRODUCTION

Biology = the scientific study of life

I. Characteristics of life:

A. Living things are organized:

1. Cells = fundamental units of life

2. Cells - tissues - organs - organ systems - organisms - populations - communities - ecosystems   

B. Living things acquire materials and energy

1. Life requires energy

2. Energy = capacity to do work

3. Metabolism = all chemical reactions that occur in a cell

4. Ultimate source of energy for life on earth is the sun through photosynthesis

C. Living things respond to their environment

1. Ability to respond helps organism survive

D. Living things reproduce

1. Reproduction involves passing on characteristics from parents to offspring

E. Living things have adaptations

1. Adaptations are modifications that make an organism suited to its way of life 

2. Natural selection is process by which species becomes modified over time

II. Science = knowledge covering general truths or the operation of general laws as obtained and tested through the scientific method

A. Science is based on:

1. Operation of natural or universal laws

2. Scientific method = principles and procedures for the systematic pursuit of knowledge:

a. recognition and formulation of a problem

b. collection of data through observation and/or experimentation

c. formulation and testing of hypotheses

B. Inductive reasoning - formulating general principles by careful investigation of specific cases

C. Deductive reasoning - application of  general principles to the investigation of  specific cases

D. Most scientific investigations involve loops of inquiry which result in the formation of a working hypothesis

E. Once a working hypothesis is formulated it may enter another series of loops in which its validity is tested

F. Experiment = a test of a hypothesis

1. Some investigations are controlled experiments:

a. Controlled experiments have a control group that does not experience the tested variable

b. Experimental variable is the step that is deliberately manipulated

G. Experiments are followed by data analyses which result in rejection, reformulation or conditional acceptance of initial hypothesis

1. Hypotheses are often conditionally accepted until independently verified by others or confirmed by further investigation

H. Eventually a scientific theory may be formulated

1. Theory = "a hypothesis supported by a great deal of evidence which stands the test of time, often tested and never rejected". E.g. theory of evolution

 I. A scientific theory must be falsifiable

J. Goals/constraints of science:

III. Diversity of life

A. Special creation - supernatural or divine force created the universe, its contents and all life forms

1. Based on faith = a firm belief in something for which there is no proof

2. Not subject to scientific investigation

B. Theory of evolution =  "changes in gene frequencies in a population over time"

1. Only scientific explanation for diversity of life on earth

2. Processes of evolution are fact:

a. Mutation - changes in genes

b. Recombination - shuffling of the genetic material between generations

• Mutation and Recombination provide variation

c. Natural selection =  differential reproduction, i.e. those with certain traits have advantages which allow them to leave more offspring, thereby increasing the proportion of their genes in subsequent generations

d. Reproductive isolation - maintains the changes produced by mutation, recombination and natural selection so that the formation of new species may take place

3. Evolution is the unifying theme of biology

4. Pope John Paul II accepted the theory of evolution

IV. Scientists who investigate the past proceed much like detectives investigating a crime without witnesses. They must assume that no supernatural forces were involved

1. Suppose you are accused of a murder and you have overwhelming evidence to prove that you were 3,000 miles away from the scene of the crime when the murder was committed

2. But the prosecutor ignores this rational evidence, and claims that you made yourself invisible, flew at the speed of light to commit the murder 3,000 miles away, and returned an instant later

3. How could you defend yourself? Could you prove that you did not have these powers? No -- it is impossible to prove or disprove something outside the realm of rational investigation

4. Any judge who heard a prosecutor accuse a defendant of using supernatural powers to commit a crime, would immediately rule that the accusation is inadmissible in court. In just the same way, the explanation of material facts by supernatural forces is not admissible in science

V. Misconceptions about theory of evolution:

A. "Evolution has never been observed" - changes in gene frequencies occur constantly, e.g. antibiotic resistance in bacteria

B. "Evolution violates the second law of thermodynamics" - second law can be stated several ways, creationists commonly use "The entropy of a closed system cannot decrease". Life is not a closed system, the sun provides more than enough energy to drive things

C. "There are no transitional fossils" - there are many transitional fossils, however, as will be discussed later in the term, we are lucky to have any fossils at all due to several of factors 

D. "The theory of evolution says that life originated, and evolution proceeds, by random chance" - Chance certainly plays a large part in evolution, but this argument completely ignores the fundamental role of natural selection, and selection is the very opposite of chance. Chance, in the form of mutations, provides genetic variation, which is the raw material that natural selection has to work with. From there, natural selection sorts out certain variations

E. "Evolution is only a theory; it hasn't been proved" - review the definition of theory "a hypothesis supported by a great deal of evidence which stands the test of time, often tested and never rejected". It is possible to prove a hypothesis false, but it cannot be proven true. Support eventually comes from accumulated inability to discredit

F. "You must accept either evolution or religion, but not both" - unless you take a literal interpretation of  certain "Holy texts" they are not mutually exclusive 

VI. Intelligent Design (ID) "Theory":

A. Maintains that life and the universe are too complicated to have arisen via natural processes and/or science can not explain everything

B. Therefore they must be the work of an "intelligent designer"

C. Most ID proponents state explicitly that they believe the designer to be the Christian God

D. Throughout history humans have invoked the supernatural for phenomena they don't understand:

1. Evil spirits cause disease vs. germ theory

2. Geocentrism vs. Heliocentrism

3. Rev. Franklin Graham (2005) - the S.E. Asian tsunami caused by satan vs. plate tectonic theory

E. ID is not a valid scientific theory because it is not falsifiable and science can not address the supernatural 

F. Courts have consistently struck down the the teaching of ID in public schools because it violates the first amendment "establishment clause". Kitzmiller v. Dover (2005) effectively spelled the end of ID  

G. August 6, 2008. Michael Medved, a Senior Fellow at the Discovery Institute which promotes ID said "The important thing about Intelligent Design is that it is not a theory - which is something I think they need to make more clear".

VII. Recent examples of evolution

A. antibiotic resistant bacteria

B. pesticide resistance

C. nylon eating bacteria

1. nylon is an artificial polymer not found in nature, developed by humans in the 1930's. By 1975, bacteria capable of breaking down nylon were found in wastewater from nylon plants

VIII. Visit the "Understanding evolution for teachers" website for a very readable introduction to the subject.