Islands

Vocabulary:

• Plate tectonics: The theory that describes how different parts of Earth’s crust are moving

• Fault line: The boundary between two plates, collisions cause earthquakes. If lava shoots up from one, a volcano is created

• Hotspot: A place in Earth’s mantle where lava pushes up through the crust to create volcanoes. This doesn’t include the plates that are still moving above them, eventually creating islands.

• Endemic species: A species who due to climate change has become extremely localized, typically the whole species in one population

• Sky islands: A term that describes a habitat that acts like an island with its own unique endemic plants and animals, commonly high in the mountains. These are still connected to land, but are called islands due to their lack of gene flow

• Anthropogenic change: Change in an environment caused by humans

• Niche partitioning: How different species can avoid competition between other species and still maximize the amount they are able to gain, by taking up different resources. Think about the finches

• Island biogeography theory: My MacArthur and Wilson in 1967, describes the types of animals that can survive on an island. Predicted there was a certain number of species an island could support over time, which was in turn a result of continual turnover of some species migrating in/out or dying off. Also proposes larger islands have more species, and the more remote an island is the less number of species it would have

• Equilibrium model of island biogeography: Smaller islands have less species, but the less remote and larger and island, the more species it is likely to have

  

There tends to be volcanoes where two continental plates come together, because this is where lava from the mantle comes up and expels itself to create rings of volcanoes. This is also how oceanic islands are formed.

Island formation

• Lava comes up to the surface, cools due to oceanic water, and forms land. This process may happen many times over and over to create an island. Continental plates are shifting, and the hotspot is in the same spot but lava comes up and pushes through, creating a new island, even though the plates have shifted to a new location.

• Sea levels change which allow for exposed sea floor, where animals and plants colonize

• Anthropogenic change, urbanization has caused species to only live in nature preserves, same thing with agriculture and deforestation

Different species will come by air or sea to a new island, and the island will only be able to sustain so many different species due to the resources it can provide