Evolution

 This unit explains the scientific aspect of evolution.  There are multiple views on evolution all of which have significant evidence for backing.  Everyone is entitled to their own opinion and we will discuss multiple views and opinions.

What is Evolution?  Evolution is a scientific explanation for the diversity of life based on a collection scientific data, observations and hypotheses.  The Theory of Evolution- Change over time by which a modern organism has descended from an ancient organism.  This unit explores multiple explanations for evolutionary change.

Charles Darwin  One of many scientists who has studied evolution.  He has contributed the most amount of data and research to the theory of evolution.  Sailed on a ship (H.M.S. Beagle) around the world, most notably in the Galapagos Islands, making observations and collected evidence which supports his theory.  Published the results of his work in the book; On the Origin of Species.

Descent with Modification  Idea that Darwin proposed also know as Darwinism:  States that over long periods of time natural selection produces organisms that have different structures, establishes different niches or occupy different habitats.

Define the Following Terms  Fossils  Artificial Selection  Struggle for Existence  Fitness  Adaptation  Survival of the Fittest  Natural Selection  Common Descent  Homologous Structures  Vestigial Organs

Darwin’s Evidence of Evolution  Darwin argued that living things have been evolving on Earth for millions of years.  His evidence for this process could be found in the fossil records, geographical distribution of species, homologous structures of living organisms and embryology.

Population Growth  The increase in number of a species as well as sustaining the existence of the species on earth.  Certain factors must occur for population growth to occur.  Many factors influence population growth.  Population growth and population dynamics can impact population genetics.  Genetics has a direct relationship to evolution.

Summary of Darwin’s Theory  Individual Organisms differ, and some of this variation is heritable (first connection between evolution & genetics).  Organisms produce more offspring than can survive (creates competition), and not all can reproduce.  The offspring will fight for limited resources in order to survive.  Each has advantages & disadvantages in the struggle for existence. Those organisms that survive, pass these traits on to their offspring.  Species alive today are descendents of those that survived in the past.

Other Thoughts of Evolution  James Hutton- Earth shaped by geological forces that took place over extremely long periods of time.  Thomas Malthus- Principle of Population, predicts that human population will grow faster then food & space needed to sustain life.  Jean-Baptiste Lamark- Says that organisms gain or lose traits based on the organisms selective use of those traits over time.

Other Thoughts of Evolution  Charles Lyell- Principles of Geology explains that processes occurring now have shaped the Earth’s geological features over long periods of time.  Alfred Wallace- Writes to Darwin about evolution by natural selection based on his study of plants & animals