I keep six honest serving men
(They taught me all I knew);
Their names are What and Why and When
And How and Where and Who. - Kipling

Campbell and Reece, Chapter 1 (but note Glossary and Index at end, and pay attention to several references to figures in other chapters)

Nature of scientific inquiry

Scientific inquiry and scientific method is based on observation - systematic, objective, repeatable
You cannot always manipulate things, examples: astronomy, studying the fossil record.
But you can make observations like the similarities in the forelimbs of birds and mammals. You can also make correlations, like overweight peope are more likely to develop type II diabetes. But correlation does not prove causation. For instance, that correlation does not prove that increasing your weight would increase your likelihood to get diabetes. Rather there could be an underlying genetic factor that could predispose you to diabetes and weight gain (in a sense, simultaneously).

Also there is experimental intervention: Propose a null hypothesis vs. an alternative hypothesis.
TRANSPARENCY (Fig. 1-19)
Hypotheses are small questions. You "test" these hypotheses - answers (in the form of "rejecting the null hypothesis") are never certain but rather involve an acceptably low probability of being wrong, hence the involvement of statistics in experimental design. Collect more data, and you will be more certain. You can only reject the null hypothesis. You can not accept (or prove) the null hypothesis. In other words, absence of data is not the same as data of absence.

In summary, the step-by-step progress of science involves statistics, and asking the right questions, that can be answered appropriately (advanced statistics) is called "experimental design."

"There are three kinds of lies: lies, damn lies and statistics"
Benjamin Disraeli (quoted in Mark Twain's autobiography, Chapter 29)

Ultimately, you develop theories (evolution), laws (gravity), or models that describe how things work (like negative feedback in homeostasis).

Biology is the study of life on Earth.

Consider the categories of substance (matter): (organic) Animal, Vegetable, (inorganic) Mineral "Is it animal, vegetable or mineral" - a question on an old quiz show called "20 questions"

Kingdoms (At one time, 2 kingdoms were proposed (plants and animals), but there were problems, for instance some organisms have properties of both kingdoms. Now 5 are generally accepted.
TRANSPARENCY (Fig. 26.15)
Sometimes more are also proposed. How can the number of kingdoms be subject to debate? Classification is not an exact science.
5 Kingdoms:
Monera (prokaryote)
TRANSPARENCY (Fig. 1.4)
These cells do not have a nucleus. The suffix "karyote" refers to the nucleus, and comes up in words like "perikaryon" (the part of a nerve cell near its nucleus) and "karyotype" (the chromosomal constitution of a cell).
The other four kingdoms have eukaryotic cells.
Protista
Fungi
Plantae
Animalia

Autotroph vs. Heterotroph (self- other-feeder)

Phylogeny vs Taxonomy
Taxonomy is sometimes called "Systematics" and is based on the Linnean system (Linnaeus 1705-1778 botanist)
Kingdom - Phylum - Class - Order - Family - Genus - Species
TRANSPARENCY (Fig. 1.10)
TRANSPARENCY (Fig. 25.7) (The point is so fundamental that it is repeated in Chapter 25, phylogeny and systematics.) Here, domain is more inclusive than kingdom
Genus - Species: binomial nomenclature
Phylum = Division for plants fungi bacteria
Homo sapiens people
Drosophila melanogaster fruit flies
Canis familiaris dogs
In phylogeny we try to draw conclusions (and diagrams) of how related organisms are. There can be various levels of artistic license in such evolutionary diagrams. Here (TRANSPARENCY) is an old (traditional) one I like to illustrate fundamental points. (There is a figure in the book TRANSPARENCY (Fig. 24.24) that is somewhat like the version I selected to show you.) Horse evolution is shown. Here is a display at the Carnegie museum in Pittsburgh. It is actually a graph. Diversity is on the X axis (abscissa). That diversity in this example is the location on Earth. The Y axis (ordinate) is time with long ago on the bottom and now on top and split up into epochs of the geological time scale (Eocene, etc.). Of note is that animals lower in the diagram are not just "simpler" animals of today. Rather, today's animals are only at the top, and some further down may be extinct, for instance, horses in the New World until they were re-introduced.
Such a diagram branches out, hence the term "divergent evolution," a concept so fundamental that you should see it now even though evolution will be covered in detail in the last quarter of the semester. One very fundamental concept is that of homology. The wing of a bird and the flipper of a porpoise are homologous and are descended from the same common structure that led to your arm and hand.
Molecular biologists borrowed this strategy and produce divergent evolution diagrams of their own (at first much to the chagrin of the comparative anatomists). TRANSPARENCY (Fig. 19.3) - let's look ahead, and we will see that your book gives an example of different components of the hemoglobin protein.

What is unique to life? Cell membrane contains protoplasm and somehow inside, cells are "alive." Cells have very complex macromolecules (DNA, RNA, protein).
Complex
Movement, Responsiveness (irritability, sensitivity)
Development, Growth, Form
Metabolism must absorb energy Catabolic, Anabolic
Homeostasis (regulation) Thermostat, servo, negative feedback. TRANSPARENCY (Fig. 1.8)
water, food. 1 cookie/day = 25 lb/yr
Evolution is major unifying principle 3 1/2 billion yrs
History from primordial "soup" of molecules to biology, extinctions, etc.
It is impossible to overstate the importance of evolution to understanding and explaining biology.
Reproduction - "Survival" in biology is to and reproduce and produce fertile offspring. In fact, that is one definition of a species (organisms that can reproduce and produce offspring - that is why the horse and the donkey are not the same species even though they can mate to produce the mule -- the mule is sterile.)
Consider this: so much energy is devoted to reproduction that reproductive structures constitute most of the human diet. Oh? Well, grain, fruit (and vegetables that are fruits), dairy products and eggs.

Levels of analysis
element - molecule - organelle - cell - tissue - organ -
organ system - organism - population - biosphere
(Biosphere - biology really change Earth)
Holism vs reductionism
Vitalism vs mechanism
Mentalism vs materialism
The attitude that "life is not driven by vital forces that defy explanation but by principles of physics and chemistry" is useful for this course, but does not touch the big questions of the meaning of life
Religion and science may seem at odds, but they can be reconciled.
Hopefully, learning biology should strengthen your appreciation of the wonder of creation.

A very useful site for SLU students, especially majors, is the Biology Department's web page.


This page was last updated 1/22/03

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