Marooned in the Galapagos

Scenario: Seeing evolution in action is often difficult, but one way to monitor evolutionary change over a short period of time is to watch what happens to species/populations in a difficult or stressful environment. The Galapagos Islands, one of the most famous laboratories of evolution and adaptation, will be explored through this scenario. Despite the islands' bleak appearance, the unusual fauna and flora of the Galapagos Islands have captivated generations of biologists since Darwin. As we tour the Galapagos Islands and their species, we will touch upon different aspects of adaptation.

Concepts Taught:

Icon Key:

activity

animation

diagram

quiz

text explanation

• Evolution
• Natural selection
• Adaptation
• Relationship of structure to function
• Adaptive radiation
• Island colonization
• Endemic species
• Dispersal mechanisms
• Species concept
• Speciation
• Reproductive isolation
• Interspecific competition
• Niche
• Variation in populations
• Coevolution

Concept Map:

1. Entire scenario

Concepts Reviewed:

• Trophic levels
• Geographic distribution
• Climate
• Thermoregulation
• Surface to volume ratio
• Biomes

In-Class Discussion and Thought Questions (also possible homework questions):

• What are penquins doing at the equator?
• What adaptations do penguins possess for life in water?
• What climatic feature has allowed this penguin to live in the tropics?
• What characteristics do these penguins have that might hinder their survival in the tropics?
• Where do the organisms (on Galapagos) originate from?
• How long would it take to travel by ocean current to the Galapagos from the nearest mainland?
• What adaptations do survivors have that helped them survive the trip to the Galapagos?
• How do organisms get to the Galapagos?
• How could we test for genetic divergence?
• What is the working definition of a species?
• What are some exceptions to that definition?
• How would you test whether the iguanas are different species?
• How do biologists decide on relationships?
• What similarities are important?
• If finches are generally seed-eaters, how is it that they eat so many different foods on the Galapagos?
• What kind of information could you gather if you could identify individuals in a population?
• In general, will the number of offspring produced each year be the number that survive each year?
• What happens to populations that have no mortality?
• What factors might produce mortality?
• How much variation in beak size and shape exists within a finch species?
• Is this variation heritable?
• How is it that genes vary?

Major Terms Introduced:

Related Laboratory Experiments :

Lab 6: How does nut diversity and abundance influence survival of birds with
             different beak types?

Text Readings:

Click here for Textbook Readings!

Corresponding Essential Study Partner Segments:

The Essential Study Partner is part of the McGraw-Hill Web Site. To access it go here. Then follow these relevant paths below:

Evolution > Processes > Natural Selection

Evolution > Processes > Variation

Evolution > Processes > Adaptation

Evolution > Speciation > Introduction

Ecology > Populations >

Ecology > Populations > Growth

Ecology > Populations > Size Regulation

Ecology > Communities > Introduction

Ecology > Communities > Organization

Many of these are figures and accompanying text, but some are video clips that should help you see the process in action.

	Natural Selection in the Galapagos - a tutorial revieiw the concepts of natural selection, coevolution, adaptive radiation, and others using examples from the Galapagos islands that we discussed in class
	Speciation - a tutorial illustration the different ways that speciation events can occur
	Adaptive Radiation - Why are there so many closely related species on islands? This tutorial reviews the processes and conditions that lead to adaptive radiation
	Speciation and Adaptive Radiation on Islands from the PBS "Evolution" Series - This is a great interactive tutorial explaining how many species can arise from one in a geologically short period of time. Based on known speciation events.
	The Mystery of the Time Traveling Iguanas - See if you can solve this puzzle - The present day Galpagos islands are 2-3 million years old, but data from molecular clocks are consistent with the divergence of land and marine iguanas occuring 12 million years ago. This web-based inquiry exercise by Arlene Weiner and Dan Suthers of University of Hawai`i at Manoa will help you.

The site for your textbook Life by Ricki Lewis

source	NSF-Evolution of Evolution
source	The Talk.Origins Archives - Exploring the Creation/Evolution Controversy Questions and answers about evolution and creationism.
source	Theory of Evolution and Evolutionary Thought, Museum of Paleontology, University of California, Berkeley The virtual museum has exhibits about evolution, as well as geology, and paleontology.
source	Galapagos geology on the web from Cornell University Includes information on climate and oceanography and Galapagos history
source	Teaching about Evolution Covers several topics in evolution and natural selection.
source	Biological El Nino Effects
source	Penguin Adaptation
source	Founder Effect
source	Natural Selection
source	Evolution and Behavior
source	Evolution Web Sites
source	Coevolution
source	Adaptive Radiation and Anoles
source	Evolution

Textbook Flashcards :

The website for your textbook has flashcards organised by chapters. You are only responsible for topics discussed in class. For this scenario, flashcards with the Major Terms Introduced can be found in:

Chapter14: The Evolution of Evolutionary Thought
Chapter 15: The Forces of Evolutionary Change-Microevolution
Chapter 16: Speciation and Extinction
Chapter 42: Populations

1. Biggs, A.L. (1990) Coevolution in the Galapagos. Am. Biol. Teacher 52: 24-28.
2. Eibl-Eibesfeldt, I. (1984) The large iguanas of the Galapagos Islands. In: Perry, R. ed. Key Environments: Galapagos. Pergamon Press, pp. 157-174.
3. Grant, P.R. (1986) Ecology and Evolution of Darwin's Finches. Princeton University Press, 458 pp.
4. Grant, P.R. (1991) Natural Selection and Darwin's Finches. Sci. Amer., 82-87.
5. Weiner, J. (1994) The Beak of the Finch. Alfred A. Knopf, 332 pp.