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Section 23_1: The Theory of Evolution

Page history last edited by Hyder Ali 10 years, 10 months ago

Grading Sheet (Hyder)

A. Learning objectives:

  1. Explain how Darwin's personal observations led to his concept of biological evolution. 
  2.  Describe how the species of Darwin’s finches have adapted to feed in different ways.
  3. Feature Investigation: The Grants Have Observed Natural Selection in Galapagos Finches


B. Section Summery: 


Evolutionis used to describe a heritable change in one or more characteristics of a population from one generation to the next.

Evolution can be viewed as:

  • Microevolution( small scale)relates to changes in a single gene or allele frequencies in a population over time
  • Macroevolution (large scale) relates to the formation of new species or groups of related species.

Species is a group of related organisms that share a distinctive form. Species that reproduce sexually are able to interbreed in nature and produce viable and fertile offspring. A  Population is all members of a species that live in the same area and are allowed to interbreed.

Darwin’s Predecessors:

Since the beginning of humanity, individuals have asked “where did we come from?” We used several methods in attempts to explain out creation/ origins. This was drastically change in Europe during the 1600’s when scholars developed and began adapting their explination to the concept of  Empirical thought. Empirical thought  relies on observation to form an idea or hypothesis rather than trying to understand life from a nonphysical or spiritual point of view.

Jumping ahead past John Ray’s studies and development of the early classification system for plants and animals based on anatomy and physiology and modification by Carolus Linnaeus (which established the basis of species) During the late 1700’s a handful of European scientists began to believe that life forms actually changed over time. Scientists like George Buffon, put foward that living things changed but were fearful and hid their ideas in large series of books only expressing the ideas very vaguely

Druing the same era Jean-Baptiste Lamarck, a French naturalist put forward an idea of  relationship between variation and evolution. Through his observation of fossils he saw that certain species changed and hypothesized that species change over generations by adapting to new environments tword “human Perfection.” He made the idea of inheritance of acquired characteristics where He thought that behavioral changes modified traits and hypothesized that such modified traits were inherited by offspring. However Lamarck’s theories were disproven by research that disproved that  acquired traits could be inherited.

Darwin and his contributions to the theory of evolution:

Charles Darwin, a British naturalist born in 1809, used biological processes and geology to make theories that played a key role in the theory of evolution.

During Darwins time Two main geological hypotheses were dominant:

  • Catastrophism: (by Georges Cuvier) states the Earth was just 6,000 years old and that only catastrophic events had changed its geological structure. This idea fit well with religious teachings.
  • Uniformitarianism: (by James Hutton) states that changes in the Earth are directly caused by recurring events. Hutton was first to propose that the age of the Earth is well beyond 6,000 years helping to shape Darwin's view of the world.

Also during his time, Darwin was influenced by a paper called Essay on the Principle of Population by Thomas Malthus. The relevant message from Malthus's work was that only a fraction of any population will survive and reproduce.

Darwin was most influenced by his own experiences and observations aboard the HMS Beagle, a survey ship, lasted from 1831 to 1836. Darwin's job was to record the weather, geological features, plants, animals, fossils, rocks, minerals, and indigenous people.  

Darwin was particularly struck by the distinctive traits of island species, for example, Darwin observed several species of finches found on the Galápagos Islands. At first, Darwin thought the birds were various species of blackbirds, grosbeaks, and finches. However, the bird specimens from the islands were given to the British ornithologist John Gould, who identified them as several new finch species.

The finches differed widely in the size and shape of their beaks and in their feeding habits (different beaks for different feeding habits). These finches all evolved from a single species similar to the dull-colored grassquit finch and changed to survive as the Galapagos islands separated and changed.

With his observations from his voyage on the Beagle, Darwin had formulated his theory of evolution by the mid-1840s.

In 1859, Darwin’s The Origin of the Species was published detailing his ideas with observational support. In this he hypothesized that existing life-forms on our planet result from the modification of pre-existing life-forms. According to Darwin evolution occured from generation to generation due to two things:

  • Variation in traits may occur among individuals of a given species. The heritable traits are then passed from parents to offspring ( gentic side not yet known)
  • The process of natural selection: individuals with heritable traits that make them better suited to their native environment tend to flourish and reproduce, whereas other individuals are less likely to survive and reproduce.



C. Useful materials:


What is evolution and how does it work? Evolution 101 provides the nuts-and-bolts on the patterns and mechanisms of evolution. This page setup by Berkeley  gives you all the graphics and explanations minus the long lectures.


This Link is especially good if you desire to delve a little deeper into variation within species. It gives a brief introduction, followed by a very short shot into classification and jumps right into the mechanisms of evolution. This section further explains the genetic variation in evolution which is vaguely described in the book. Lastly the link sums up Speciation and Macroevolution and even shows some modern-day application of the concepts.


Explore the Seven parts Highlighted in blue.


Evolution is both fact and theory! This link shows the major patterns of change in nature, how these changes occur, and fossil and genetic evidence of change. Once again summing up the basics of Evolution with an added plus. 


This Link really analyzes that Scientific understanding requires both facts and theories. It uses this to show how the idea of "evolution" was made and is proved. This page also covers the mechanisms and patterns of evolution. However it has an added bonus of showing evidence of evolution through fossils, genetics and current occurrences in the world of biology such as finding treatment for HIV


Evolution In Two Minutes! The title really sums up what this video is about. If you want an added video to supplement your reading without the long, slow pace of a lecture this video is for you.


In this video a PhD in evolutionary biology from UNC explains the basics of the theory of evolution and how it works. He describes what evolution is, what the theory says, and how it works to change species. This is a very streamlined explanation so i would recommend it as a side to other sources. 



What Is Evolutionary Theory is a lecture given at The Santa Fe Institute by Richard Lewontin, the schools science director. This lecture will discusses the origins of the theory of evolution,


Next, Lewontin discusses  what the basic structure of Darwin's theory was and what evolutionary theory is really meant to explain. Lastly He explains how the modern understanding of the process of evolution is different from Darwin's original idea. He goes beyond discusses what the deep problems of evolutionary explanation are and why evolution differs from the usual simple model of what is required of a science.


This lecture helps give a "higher education" analysis of the theory, like that which Dr. Weber may give. For just the basics of the theory watch the video until 47:35 but I highly encourage watching the entire lecture, it is a true jewel with no biases or opinions.  


This link maintained by Palomar College of California gives a very detailed  explanation of the modern theories of evolution. If you want to gain knowledge of what evolution started as and what it has become this link is for you.


I recommend reading the overview, natural selection, and macro/micro evolution sections to stay within this section. This link gives an intro into the theory but in a much more advanced method. This is followed by more genetic basis of natural selection and ends with a comprehensive look into macro and micro evolution.

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[Bonus Series]  Ever wonder why we learn about in evolution in our school geared toword "health and medical sciences"? Well you should!This a a series of videos by The National Institute of Health. These videos are not needed for this section but I believe they are great for anyone who wants to enlighten themselves into how we can use evolution in our future careers.


This video series hits on evolution and : medicine, education, genomics, and education. Even if you are not interested in any of these fields I highly recommend viewing the first lecture because it hits on what we are and will be studying for the next year and a half.  


[Just for laughs] Intoxicate your mind a bit after learning evolution with some adult humor on evolution. WARNING: THIS IS NOT AN ACCURATE SOURCE FOR EVOLUTION. THIS CONTAINS MILD ADULT HUMOR AND SOME LANGUAGE THAT MAY BE OFFENSIVE..... enjoy


D. Primary Literature: (http://www.jstor.org.ezproxy.raritanval.edu/stable/3061687?&Search=yes&searchText=theory&searchText=darwin&searchText=evolution&list=hide&searchUri=%2Faction%2FdoBasicSearch%3FQuery%3Dtheory%2Bof%2Bevolution%2Bdarwin%26Search%3DSearch%26gw%3Djtx%26prq%3DOptimization%2BTheory%2Bin%2BEvolution%26hp%3D25%26acc%3Don%26aori%3Da%26wc%3Don%26fc%3Doff&prevSearch=&item=5&ttl=32705&returnArticleService=showFullText )

F. Virtual Lectures:





G. Lecture Slides


H. Practice Quiz

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