Welcome to the Galapagos!

Welcome to the Galapagos, All-Stars!

Today we'll be exploring the Galapagos. What did Darwin see? What have scientists noticed since then?

Instructions: Read about the Galapagos. Work with your table to figure out what type/s of tortoise live on your island. Write the answers to the questions in your science notebook. These will be checked tomorrow.

Introduction
Darwin visited the Galapagos in the 1830s as a naturalist on board the HMS Beagle. Since then, scientists have learned TONS about the geology, ecology, and oceanography of the area.
The Galapagos Islands are on the Nazca Plate. The Galapagos Islands were created/are being created by a magma plume that is creating hotspot volcanoes. The oldest islands are San Cristobal and Espanola. Isabella is still active. Look at the Google map of the Galapagos Islands.

Where Darwin travelled

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The climate of the islands is closely tied to ocean currents around the islands.

Life on the islands is unique and fragile. The Galapagos islands are a major are of concern for conservation. 

Giant Tortoise Adaptation Mystery

With your table, see if you can determine which type of tortoise would live on your island.

Tall Prickly Pear Cactus

Many of us have heard of Darwin’s finches but equally important to Darwin’s observations were tortoises.
Giant tortoises in the Galapagos eat prickly pear cacti. There are two types of prickly pear cacti. One type grows low to the ground, sprawling out. It grows in richer, wetter soils. The second is taller with thick bark and fruit only at the top. This variety grows in dry and wet areas.

Shrubby Prickly Pear Cactus

Human activity and feral animals (goats, pigs, etc.) are causing the tortoise numbers to fall.
There are two main types of tortoises - tortoises with saddle-shaped shells and tortoises with dome-shaped shells.

Saddle-back Tortoise

Saddle-Backed Tortoises:
The saddle-shaped shelled tortoises are more common. They have necks that are longer and that can stretch further because their shells allow more space for stretching. They tend to live in arid (dryer) climates. Saddle-backed tortoises are more aggressive than dome-backed tortoises. They have contests to see who can stretch their neck higher.

Dome-Backed Tortoises:
The dome-backed tortoises tend to live in moister highlands. They eat plants that are lower to the ground. Dome-backed tortoises are calmer than saddle-backed tortoises. Dome-backed tortoises are built like tanks that can smash through dense underbrush. Generally, dome-backed tortoises are smaller than saddle-backed tortoises.

Dome-backed Tortoise

Questions:

1) Which tortoise do you think is well-adapted to survive on your island? What evidence is there to support your conclusion?

2) Why might you see different tortoise types on one island?

3) Coevolution is when two species evolve with certain traits because of how they live together. Discuss with your group how you think the prickly pear cacti and tortoises may have coevolved. Write down what you think.

4) Look back at the map of the islands. Which direction is the Nazca plate moving?

5) What type of rock are these islands mainly made out of?

6) How does geology and climate affect biology?

Prepare to tell the class about your island and which tortoise would live on it.

Happy Exploring!

Ms. Nickel

Sources:

http://kids.nationalgeographic.com/kids/animals/creaturefeature/galapagos-tortoise/
http://animals.nationalgeographic.com/animals/reptiles/galapagos-tortoise/
http://people.rit.edu/rhrsbi/GalapagosPages/Tortoise2.html
http://www.smithsonianmag.com/travel/evotourism/Evotourism-World-Tour-Galapagos-Islands-Ecuador.html#