Lab Manual

• How many different species of Darwin's finches inhabit the Galapagos, and what is one of the most obvious ways in which the species differ? Which two species occur on Daphne Major?

  13. Size and shape. Cactus Finch and Medium Ground Finch.
• How do the Grants monitor the individual finches in the Geospiza fortis population on Daphne Major? (Note details of how they catch, mark, and watch them.)

  They use binoculars, and have labeled each bird with a numbered and colored band. They catch the birds with nets. They take measurements of the width and length of the beak, their weight, length of the leg, and take their blood.
• What is the main food available to the Daphne Major ground finch population during periods of general food scarcity?

  Seeds
• The population of ground finches on Daphne Major shows considerable variation. In 1977 there was a very severe drought on the island coinciding with the Grants' research. What happened to the finches during the drought? Describe how the size of the finches and their beaks interacted with changes in the availability of their food.

  Many of them starved and died - about 4-500 of the smaller finches. Only the larger beaked finches could split open the larger seeds that were more available. This event selectively penalized the small beaked birds.
• What trait did the survivors of the drought pass on to their descendants?

  Deeper beak, and becoming larger.
• There was a severe El Nino event in the Galapagos in 1982-83. What weather conditions occurred, and how did this event influence the Daphne ground finches?

  Continuous rainfall - it rained for 8 months. The population grew from 150 to 1000. The seeds that were more available in drought became more scarce. So natural selection favored birds with smaller bills. Once again, the larger ground finches died and the species moved towards a new evolution.
• Considering the consequences of the drought and El Nino together on the finches of Daphne Major, what can you say about the directionality of natural selection when mediated by environmental change?

  It can change in size in one direction and then reverse. The population will fluctuate back and forth with the long term average set by the long term average of food conditions on the island.
• What does the film's title, "What Darwin Never Saw", mean? Do studies like that of the Grants' suggest that Darwin was correct in thinking that evolution by natural selection is a very slow process, always taking many thousands of years to produce an obvious change?

  The films title indicates that Darwin didn't get to see the natural selection happening in person. The Grants confirmed natural selection, but their study showed that physical changes can happen within a short period of time.
• What is thought to be the origin of the 13 species of Darwin's finches in the Galapagos?

  The original bird or birds that flew over from South America.
• What are some of the major conservation problems facing the Galapagos Islands and the animals inhabiting them today? How are these problems being addressed?

  Invasive species, overfishing, and tourism impact are major conservation problems in the Galapagos Islands. These problems are being addressed through measures such as eradication programs, fishing regulations, and sustainable tourism practices.
• The Galapagos islands were visited by the naturalist Charles Darwin in 1835 during his five year round-the-world voyage on the survey ship H.M.S. Beagle.
• What Darwin saw in the Galapagos had an important influence on his thinking about the mechanism of evolution, and in this century, the islands have become a "living laboratory" for evolutionary studies.
• The film, "What Darwin Never Saw", focuses on the long-term evolutionary studies by biologists Drs. Peter and Rosemary Grant on the finches of the Galapagos, and particularly on their studies of the population of Darwin's medium ground finch on the tiny island of Daphne Major.
• The scientific method is a way of gaining knowledge that uses a specific set of techniques to investigate phenomena.
• What are the integral steps in the Scientific Method?

  1. A question is formulated based on observation of natural phenomena.
  2. A hypothesis is developed to describe or explain the phenomena.
  3. Predictions based on the hypothesis are tested by experiment and collection of measurable evidence
  4. The hypothesis is either rejected or not rejected based on this evidence.
  5. If the hypothesis is rejected then it is revised based on the experimental observations, and the revised hypothesis is then tested.
• It is the creation of a falsifiable or refutable hypothesis and the experimental testing of this hypothesis that distinguishes the scientific method from other ways of knowing (e.g. philosophy, religion).
• The ability to revise and re-test an incorrect hypothesis is an important part of science.
• A hypothesis or a group of related hypotheses that have been confirmed by extensive experimental testing may become a theory. An example is the theory of gravity.
• Scientific theories are well-supported explanations of natural phenomena, and are the basis for development of new scientific knowledge.
• Name that step in Scientific Method!: What do I see in nature? This can be from one's own experiences, thoughts, or reading.

  Make Observations
• Name that step in Scientific Method!: Why does that pattern occur?

  Think of Interesting Questions
• Name that step in Scientifc Method!: What are the general causes of the phenomenon I am wondering about?

  Formulate Hypotheses
• Name that step in Scientific Method!: If my hypothesis is correct then I expect a, b, c....

  Develop Testable Predictions
• Name that step in Scientific Method!: Relevant data can come from the literature, new observations, or formal experiments. Thorough testing requires replication to verify results.

  Gather Data to test predictions
• In the scientific method, after you gather data to test predictions, what are the two directions you can after that?

  1. Refine, alter, expand, or reject hypotheses
  2. develop general theories (this can also be done after re-testing)
• Name that step in Scientific Method!: General theories must be consistent with most or all available data and with other current theories.

  Develop general theories
• When an object is dropped from a desk, it will fall to the ground. Is this hypothesis falsifiable?

  Yes
• All green apple are sour. Is this hypothesis falsifable?

  No. You need a specific population, not the entire world. Sour can also be relative between people.
• Bipedal walking (walking on two legs) is a more energetically efficient form of locomotion than quadrupedalism (walking on four legs). Is this hypothesis falsifiable?

  Yes. You can talk about calories expended and make equations.
• DNA, deoxyribonucleic acid, is the molecule that carries hereditary information. All the genetic information about growth, maintenance, function, and reproduction is stored here.
• DNA is stored within the nucleus of eukaryotic cells, and is usually wound tightly into a structure called a chromosome.
• What kind of cells are we made up of?

  eukaryotic cells
• What kind of cells are bacteria made up of?

  Prokaryotic cells
• What is the difference between eukaryotic cells and prokaryotic cells?

  eukaryotic cells have a nucleus while prokaryotic cells do not.
• How many pairs of chromosomes do we have?

  23
• The simplest functional subunit of DNA is called a nucleotide.
• A nucleotide is made up of:

  1. 1 phosphate group
  2. 1 sugar molecule (deoxyribose)
  3. 1 base
• There are 4 different types of nucleotides in DNA. Each have the same phosphate and sugar but differ in type of base. There are 4 types of bases: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
• A single strand of DNA consists of many nucleotides linked together by bonds between the phosphate and sugar molecules - a polynucleotide chain.
• A DNA molecule is made up of 2 strands of DNA joined together by weak hydrogen bonds between each pair of bases. The 2 bases fit together like puzzle pieces, but only specific bases bond together.