1.  Evolution by Natural Selection
Evolution is the genetic change in populations of organisms change over time, sometimes resulting in new species.
One of the basic mechanism for this change is natural selection, along with mutation, migration, and genetic drift.

1.  There is variation in traits.

Example:  Some beetles are green and some are brown.

2.  There is differential reproduction.
Since the environment can’t support unlimited population growth, not all individuals get to reproduce to their full potential.

Example:  Green beetles tend to get eaten by birds and survive to reproduce less often than brown beetles do.

3.  There is heredity.
The organisms with the ability to survive get the chance to reproduce and pass on their genetic traits.

Example:  The surviving brown beetles have brown baby beetles because this trait has a genetic basis.

 End result:
The more advantageous traits allow the survivors to have more offspring, making their genes more common in the general population, thus changing the gene frequency over time.

Example:  The brown coloration being the more advantageous trait allowed those beetles to have more offspring, becomes more common in the population.  If this process continued, eventually all individuals in the population would be brown.  Thus, natural selection was the mechanism by which gene frequencies changed over time.

If you have variation, differential reproduction, and heredity, you will have evolution by natural selection as an outcome.

2.  Taxonomy
Classifying organisms according to similarities in patterns of embryological development and adult anatomical and physiological characteristics

The Eight Taxons—levels of classification—are:
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

 3.  Cell Theory
? All living things are composed of one or more cells.
? All cells arise from preexisting cells.
? Cells are the basic units of life.

4.  Homeostasis
Organisms are able to tolerate varying external conditions by maintaining a stable internal environment.  The manner in which they do so is the study of physiology.

5.  Bioenergetics
The biology of energy transformations and energy exchanges (as in photosynthesis) within and between living things and their environment.
This flow of energy through living systems, making and breaking chemical bonds in the biological molecules found in living organisms, operates according to the same rules that governs energy in the physical universe.
Bioenergetics is the study of thermodynamics applied to living systems.

6.  Gene Theory—the Theory of Inheritance
How characteristics of one generation are derived from those of earlier generations.
Traits, or characteristics, are passed from one generation to the next by means of hereditary factors called genes.
Genes are located on chromosomes and consist of DNA.  DNA is the primary information-bearing molecule of life.  DNA is passed from parent to offspring through reproduction.

 7.  The Theory of Ecosystems
Ecosystems are organisms interacting with each other and with their environment—and a change in any biological or physical part of an ecosystem causes change throughout the entire ecosystem

Review Questions

What is evolution by natural selection?

What are the three major components of natural selection?

Arctic rabbits have fur that turns white in the winter time, helping them to blend in with the snow and avoid predators.  Explain how natural selection could affect arctic rabbits if the weather patterns were to change and not as much snow fell, or winter began later in the year and lasted for a shorter period?

What is taxonomy?

What are the three parts of the cell theory?

What is the biological theory of homeostasis?

What is the theory of bioenergetics?
Is there any difference in the chemical reactions that take place and living things and the reactions that occur in the non-living world?

What is the gene theory, or theory of inheritance?

What role does the molecule DNA play in gene theory?

What is the relationship between genes, chromosomes, & DNA?

The youngest major theory in biology is the theory of ecosystems.  What is that theory?
 
 
 

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REVIEW & DO NOW Answer the following questions:
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