Objective: This learning unit should help the learners to understand the island theory and the natural selection. Both theories are important to recognize how the Darwin finches could spread into different varieties on the Galapagos islands and get such a big diversity.
Learning outcomes: Learners are able to understand how a population behaves if it settles on a new island.
Previous knowledge: first contact activity from the same topic
Duration: 30 min.
Materials / Conditions: pictures provided, internet access
Methods / Techniques: research and transfer
Learning subject: Biodiversity / Module I: Introduction to biodiversity / Level: advanced learning
The Darwin finches came to the Galapagos islands as migrants. This species was influenced by many factors. In this activity you will get to know the “island theory” and the “natural selection”.
1. In the resources (material 1) you can find three diagrams. Analyze and explain them in your own words. Which factors have which influence on the population on the island?
2. Do you know some animals that came to Cabo Verde which displaced native animals in the past? Write their names down. How did these animals come to Cabo Verde?
3. Read the text and look at the pictures of the following link:
Source Portuguese: http://www.sobiologia.com.br/conteudos/Evolucao/evolucao17.php
Source English: http://www.bbc.co.uk/bitesize/higher/biology/genetics_adaptation/natural_selection/revision/1/ (retrieved: 08/31/2015)
Explain the natural selection in your own words.
4. Present how the natural selection and the Darwin finches are in correlation and how it effects them.
Material 1: Number of species on islands under different variables
Possible results / Results:
1. The number of extinction and immigration influenced each other. If the immigration rate rises, the extinction rate does the same. Its the same in reversal.
If immigrants come to a small island, the extinction will be bigger than on a large island.
Immigration on a far island is more mortal for the population than on a near island.
2. Depends on knowledge of learners.
3.The natural selection means the survival of the fittest. The individual which is the most adapted to its environment has the biggest chance to survive and spread its genes.
4. The Darwin finches are perfectly adapted to their environment. With its 14 subspecies its dominating many niches. The species which survives over 100 of years had to go through the natural selection.
Author: Philemon Kiduma