Chapter 1: Life

The Scientific Method (pages 15 - 21 in Solomon text).

Hypothesis : is an idea that can be tested ( Fig 1-17).

Prediction : the logical consequence of a hypothesis.

Experiments are often designed to disprove the hypothesis (it is easy to disprove an idea, but virtually impossible to prove it). Example of the scientific method: coral snakes

The experimental group differs from the control group usually in one variable eg testing new medications.
Placebo : a pill or injection that contains no medication (used in testing pharmaceutical drugs).

Sample size : the larger the sample, the more accurate the results.

Theory : a scientific theory has been supported by many experiments
eg atomic theory, the theory of evolution.

"The mere formulation of a problem is often far more essential than its solution, which may be a matter of mathematical or experimental skill. To raise new questions, new possibilities, to regard old problems from a new angle requires creative imagination and marks real advance in science" Albert Einstein

Characteristics of Organisms (pages 2 - 6)

1) Composed of cells : either one cell (unicellular) or many cells (multicellular). Fig 1-1.

2) Growth and development.

3) Metabolism means all the chemical reactions in the body.
Homeostasis: means keeping the internal environment constant.

4) Move : for example using cilia or flagella Fig 1-2.

5) Respond to the environment

6) Reproduction: sexual (offspring vary from each other) or asexual (offspring are identical clones). Fig 1-4.

7) Evolution (species change over time).

Evolution (pages 8 - 13)

All populations slowly change over time. Charles Darwin and Alfred Wallace explained the theory of evolution in 1859:
1) All organisms produce many offspring, that are all different.
2) Most of the offspring die young before they can reproduce.
3) The few that survive have genes that adapt them to the local environment, so nature selects the best genes.
4) Over time the population slowly becomes better adapted.

This process is called: natural selection (nature "selects" the best in each generation). Later the term "survival of the fittest" was used.

Biological classification (pages 9-10)

This was invented in 1753 by Linnaeus. The example below is the classification of the leopard:

      Kingdom                 Animal
					
      Phylum  ( Phyla )       Chordates
				
      Class                   Mammals				

      Order                   Carnivores					

      Family                  Cats					

      Genus   ( Genera )      Panthera
				
      Species                 pardus

The scientific name is the Genus name followed by the species name, for example Panthera pardus.

Members of the same species can breed and produce fertile offpsring, so two leopards can produce cubs. Members of different species cannot breed (like leopards and lions).

Last edited August 2009, David Byres, dbyres@fscj.edu