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Chapter 1 Introduction: Themes in the Study of Life
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Introduction: Themes in the Study of Life
Biology-The Study of Life
Definitions of Life
The sum of the functions by which death is resisted
A predicament preceding death
"For what is life? It is even as a vapour that appeareth for a little time and then vanisheth away"
Characteristics of Life
1. Basic Elements (protoplasm)- Carbon, hydrogen oxygen, nitrogen and several others.
These elements are arranged into the major compounds of life-Carbohydrates, proteins, lipids, nucleic acids, water.
Even though we all share the same basic elements they are arranged differently in each one of us.
2. Cellular organization-all life forms are composed of cells except________?
Some organisms are composed of only 1 cell. In a multicellular organism the cells have become specialized
Examples-nerve cells, muscle cells,blood cells, liver cells, lung cells, etc.
3. Exhibit growth-all living things become larger at sometime during their life
Cells increase in number (mitosis) and size.
You started out as 1 cell this big .
4. Derive energy from food-all living things require a source of energy;in living things the energy in food is converted to a usable source of energy in the form of a compound known as ATP= Adenosine-triphosphate.
5. Maintain Homeostasis
Homeostasis- the ability of a living organism (within limits) to maintain a constant internal environment even though the external environment is changing. Temperature, atmospheric pressure, moisture, etc.
6. Show species adaptations- which are passed on to their offspring.
Examples- polar bear, fish, cactus plant.
7. Reproduction-all living things must have some method to reproduce themselves. If they don’t then they become________?
Reproduction may be Asexual or Sexual.
8. Change through mutations (Evolve)
A mutation is a change in the DNA(genes) that are passed on to offspring.If a mutation is helpful then it will enable the species to adapt to a changing environment.
Mutations that are harmful may cause a species to become extinct or diseased.
9. Living things have regulatory mechanisms that allows them to maintain a certain internal environment.
These regulatory mechanisms are called feedback mechanisms and they may either be negative or positive.
Subdivisions of Biology According to Subject
Anatomy
Physiology
Taxonomy (fig.1.10)
Genetics
Embryology
Ecology
Evolution
Biochemistry
Paleontology
Classifying Life
Diversity is a characteristic of life
Biologists have identified and named about 2 million species. Many remain unidentified (10 million more)
Life is classified into 7 major groups
Kingdom
Phylum
Class
Order
Family
Genus
Species
The Methods of Biological Research
The Scientific method
1. Selection or observation of a problem
2. Hypothesis
3. Experimentation
4. Theory>>Law
Examples of Theories- Cell, Atomic, Gravity, Evolution.
When experimenting it is best to test one variable at a time.
Synergism- the joint action of agents, such as drugs, that when taken together cause an effect that is greater than each one taken separately.
Alcohol + Sleeping pills__________?
Cocaine + Heroin ___________?
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Inductive and Deductive Reasoning
Inductive reasoning- proceeds from the specific to the general. Example-all plants are composed of cells, all animals are composed of cells, bacteria are composed of cells, amoebas are composed of cells. Therefore: All living things are composed of cells
Deductive reasoning-Proceeds from the general to the specific.Also known as If-Then reasoning.
Example-If all living organisms are composed of cells and humans are living organisms Then humans are_________?
Both are used during a scientific investigation.
Science is concerned with the known---the observable, the factual and the predictive.
Religion is concerned with the unknown and is based on faith. Science cannot prove or disprove the existence of God because these are matters of faith to which the scientific method cannot be applied.
Forms of Science
Pure or basic science- to further mans knowledge of the world. May or may not have a practical use.
Applied science or Technology-any attempt to apply the knowledge of pure science for the betterment of mankind. Applied science is dependent on pure science.
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