Welcome to Islands

The Story: This unit is about both biological and geological evolution. Islands provide interesting, unusual examples of evolutionary change on a scale that is small and easy to understand. While the results of island evolution tend to be very different from evolution on a continental landmass, the mechanisms are the same. Islands simply become the context to learn evolutionary mechanisms. Islands Unit Overview

Student Outcomes:  Understand the process of biological evolution on isolated island systems.  Observe the results of biological evolution and describe the specific mechanisms that drive it.  Connect the unique biological evolution of organisms on an isolated island system to the island’s geology.  Gain an understanding of earth’s geological processes involved in island formation by observing evidence of plate tectonics, and rock samples.

I. What is an island? Definition: Islands are isolated environments with unique living organisms (biology) and unique physical characteristics (geology) II. Why do we study islands? Islands are dynamic and often experience change, both biologically and geologically, more rapidly than continental landmasses Islands are smaller than continents, therefore easier to study. Islands allow us to study two major themes in science: Evolution (Biological Science) and Plate Tectonics (Earth Science). III. What is unique about islands? Islands are isolated environments formed from unique geological processes, which leads to biological diversity not found on large landmasses.

Giant Galapagos Tortoise - Galapagos Dodo Bird - Mauritius Kiwi Bird - New Zealand Giant burrowing cockroach - Australia IV. Species on islands are unique. Identify unique adaptations found in the organisms below.

Rattleless rattlesnake - Santa Catalina Island Tasmanian devil - Tasmania Komodo dragon - Komodo Island Tree climbing kangaroo - New Guinea

Mauritius Madagascar GalapagosTasmania New Zealand New Guinea Indonesia Santa Catalina

V. Islands are unique because they are similar. All islands are unique in that they have their own physical and biological characteristics. Islands are similar in:  the mechanisms that create them  biological diversity due to an isolated environment

VI. Similar factors affect island organisms. 1. Dispersal Ability - pioneer species are good at migrating to new locations 2. Size Change - organisms are larger or smaller than normal 3. Loss of Dispersal Ability - species easily lose ability to emigrate 4. Endemism - species tend to evolve and remain native to that area only 5. Relictualism - populations are small and have a greater chance of extinction 6. Loss of Defensive Adaptions - defense capabilities are reduced in predator-free environments 7. Archipelago Speciation - many species may evolve from one in the same island group 8. Adaptive Radiation - many species may evolve from one in the same location because they use different parts of the habitat