| 
  • If you are citizen of an European Union member nation, you may not use this service unless you are at least 16 years old.

  • You already know Dokkio is an AI-powered assistant to organize & manage your digital files & messages. Very soon, Dokkio will support Outlook as well as One Drive. Check it out today!

View
 

23-1: Feature Investigation: The Grants Have Observed Natural Selection in Galapagos Finches

Page history last edited by Peter Falk 12 years, 11 months ago

Section Summary: 

 

     This material is drawn from the Feature Investigation in Chapter 23, Lesson 1 "The Grants have Observed Natural Selection in Galapagos Finches". The study is based on the work of Peter and Rosemary Grant, who went to the relatively isolated island of Daphne Major (a part of the Galapagos chain). It is important to note the isolated nature of the island because it was this fact that allowed the Scientists to study a significant portion of the population, without it being spoiled by factors such as migration. Anyways, the scientists were out to test the hypothesis that the population of Birds with long beak sizes increased as a reaction to droughts, because the larger beak size allowed the birds to eat the thicker, tougher seeds, and in times of moist climate the birds with smaller beaks would see a population increase because of the proliferation of small seedlings that are easier to capture for the birds with small mouths.  To test this hypothesis, the scientists and their colleagues measured the beak sizes of as many birds as they could get their hands on, and observed how it changed as a response to the changing climate. They were able to observe that the birds with longer beaks did in fact increase in population during drought versus birds with smaller beaks, and the overall average beak size increased. It is important to note that these changes are being observed from year to year, not across many generations as suggested by previous theorists. Over the course of about two to three years, the Grants were able to witness Natural Selection at work, and provide data that showed the population of the birds changing as result of changing environmental conditions. The birds that were better suited for the environment survived, and the birds that weren't as well suited for their environment didn't survive/  

 

Prezi & Virtual Lecture:

 

 

 

Virtual Lecture:

 


Useful Materials: 

 

This lecture from Stanford University has Peter and Rosemary Grant (The one and only), discussing the Legacy of Darwin and explaining how and why species multiply. This is an interesting lecture, and it is a worthwhile listen for anybody who is interested in going more in-depth on the evolution topics we discuss. It is also unique to read about a scientist or researcher in your book, and then actually get to see them discussing their subject material in modern times. Pro-tip: The actual lecture starts at 13:00. 

 

Grants' Finch Study Data 

 

This .pdf from PBS provides more in-depth data about the information that the Grants gathered in their escapades at Daphne Major. The extra graphs show a very stark and obvious correlation the population size and the seed abundance. These graph illustrate the importance of adapting to environment. Overall, this document is a nice supplement to the basic graph that is included in the textbook. 

 

 

Unpredictable Evolution in a 30-Year Study of Darwin's Finches

 

This article is the culmination of all of the Grant's collective patterns in the study of evolutionary patterns of Finches in the Galapagos Islands. It summarizes all of the data and observations they made across their extensive studies of Finches in the picturesque islands.

 

 This image is taken from the article. This image shows how difficult it s to predict phenotypical patterns of a population over long periods of time, because of the various changing factors, primarily environmental. This graph analyzes the data over the course of thirty years, whereas the main study focused on this selection is only over the course of a few years.  

 

Persistence of song types in Darwin's finches, Geospiza fortis, over four decades.

 

This article discusses a different type of trait that has been observed in the "Darwin's Finches" and how it has changed over the decades. This article shows how not only do beak sizes demonstrate the process of natural selection at work from generation, but the song types can be observed to change over the course of decades as per the natural selection idea. 

 

Heres a little flow chart that explains the basic process of how the changing seed sizes affects the beak length. 

 

This an image from the book that goes over all of the aspects of the study, including procedure, hypothesis, conclusion and data. It is useful to have all of this information in one place for studying. 

 

This is a picture of Peter and Rosemary Grant from 2009.

 

Comments (0)

You don't have permission to comment on this page.