Islands Introduction Islands are similar because they are unique

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? A.Definition: Islands are isolated environments with unique living organisms (biology) and unique physical characteristics (geology) II. Why Do We Study Islands? A. Islands are similar because they are unique B. Islands are dynamic and often experience change, both biologically and geologically, more rapidly than continental landmasses C. Islands are smaller than continents, therefore easier to study. D. Islands allow us to study two major themes in science: Evolution (Biological Science) and Plate Tectonics (Earth Science). III. What Happens to Organisms on Islands Over Time? A. Migrate, Survive, Reproduce, Adapt, Evolve or Go Extinct

IV. Effects Are Unique on Islands A. Species on islands are unique. B. Identify unique adaptations found in the organisms below. Giant Galapagos Tortoise - Galapagos Elephant Bird (extinct) - Madagascar Dodo Bird (extinct) - Mauritius

IV. Effects Are Unique on Islands (continued) A. Species on islands are unique. B. Identify unique adaptations found in the organisms below. Kiwi Bird - New Zealand Giant burrowing cockroach - Australia Moa (extinct)

IV. Effects Are Unique on Islands (continued) A. Species on islands are unique. B. Identify unique adaptations found in the organisms below. Pygmy hippopotamus - MadagascarRattleless rattlesnake - Santa Catalina Island Tree climbing kangaroo - New Guinea

IV. Effects Are Unique on Islands (continued) A. Species on islands are unique. B. Identify unique adaptations found in the organisms below. Tasmanian devil - Tasmania Komodo dragon - Komodo Island Lesser bird of paradise - Indonesia

V. Causes Are Similar on Islands A. The mechanisms that cause islands to be unique are similar: 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 Adaptations - 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

VI. Mechanisms For Evolution are Similar on Islands A. Natural Selection - “Best Fit” Survive Ex. Camouflage, size, speed, adaptations, sex appeal, strength, intelligence, predictable human impact etc. B. Genetic Drift - “Lucky” Survive A. Ex. Extreme weather, isolation, epidemic diseases, genetic mutations, unequal gender balance, geologic activity etc.

Mechanisms of Island Evolution Numbers on these slides correspond to your HW. Presentation Highlight information in blue. What Biological Processes Make the Organisms on Islands So Unique?

Dispersal 1. Define dispersal: The process of scattering or spreading from a certain area. 2. Give examples of how plants disperse their seeds. Birdschance Windchance Floatchance Shoots out of fruitnatural Spring open and scatternatural 3. Analysis: How is dispersal important to evolution on islands? How life arrives.

Evolution and Natural Selection Evolution - The process of modern organisms descending from ancient organisms; change over time. 4. Variation Variations will be selected for or against. Organisms with more adaptive variations are more likely to survive and pass on their inherited variations. Fitness - Organisms with more successful offspring have a higher fitness: the combination of physical traits and behaviors that help an organism survive and reproduce in its environment. Measured by the number of successful offspring. Charles Darwin

Evolution and Natural Selection 5. Survival of the Fittest - Individuals with characteristics best suited to their environment survive. 6. Natural Selection - The process in nature that results in the most fit (best adapted) organisms producing offspring. 3 steps: variation --> selection --> reproduction. The mechanism that drives evolution. 7. Adaptation - The process that enables organisms and species to become better suited to their environments.

Evolution does NOT occur in the following ways: A Desire to Change Use and Disuse Passing on Acquired Traits Evolution and Natural Selection

8.What is genetic drift? Give 2 examples. Genetic change in a population, occurring in the absence of natural selection, due to random, chance events. Separation of populations so that they do not interbreed to produce fertile offspring. One of the most common ways in which new species form is when populations are separated. Examples of events leading to genetic drift: -mutation -chance dispersal -extreme weather -Geographic barriers Evolutionary Theory Evolves: Genetic Drift

Evolution of new species: Speciation  Speciation - The process of new species evolving from pre- existing ones. This may be due to natural selection, genetic drift, or both.  Niche - The combination of an organism’s habitat and it’s role in that habitat. (address + profession) Why can no two species occupy the same niche? Competition arises for food and space. The most efficient species will survive and reproduce. Darwin’s Finches

Punctuated Equilibrium - Rapid periods of speciation (evolution) due to genetic drift and other random (stochastic) factors after long periods of gradualism (deterministic) Rapid speciation may occur when a small population of a species becomes isolated from the main part of the population or due to other factors. Evolutionary Theory Evolves: Genetic Drift

9. How are genetic drift and natural selection different? Evolution by natural selection occurs predictably, slowly and gradually. Evolution due to genetic drift is unpredictable and to some degree random (stochastic) 10. How are genetic drift and natural selection similar? Both lead to change over time (evolution). 11. Analysis: What is unique to the evolutionary process on islands and why? Islands are ISOLATED (distant) and small so genetic drift is more likely. AND factors influencing natural selection may be different. Evolutionary Theory Evolves: Genetic Drift