Island Biogeography
Kate Anderson
7 min read
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Study Guide Overview
This study guide covers Island Biogeography Theory (IBT), focusing on the relationship between island size, distance, immigration, and extinction rates, and their effect on species richness. It also explores invasive species, their characteristics, impacts, and the contrast with endemic species. Finally, it touches upon evolutionary concepts like adaptive radiation using Darwin's finches as an example and provides practice questions for the AP Environmental Science exam.
#AP Environmental Science: Island Biogeography & Invasives - Your Last-Minute Guide 🚀
Hey there, future AP Environmental Science superstar! Let's get you feeling confident and ready to ace this exam. We're diving into Island Biogeography and Invasives, two topics that often pop up and can be real game-changers if you know them well. Let's break it down!
#Island Biogeography Theory: The Basics 🏝️
#What's the Big Idea?
Island Biogeography Theory (IBT) explains how the size and location of an island affect the number of species that live there. It's all about the balance between immigration (new species arriving) and extinction (species dying out). Think of it like a bustling city: people move in, and people move out, and there's a sweet spot where things are stable.
The core of IBT lies in understanding the dynamic equilibrium between immigration and extinction rates.
#Immigration vs. Extinction
- Immigration: New species arrive on the island.
- Extinction: Species already on the island die out.
Initially, immigration rates are high because there are open niches. As more species arrive, competition increases, and extinction rates rise. Eventually, these two forces reach an equilibrium, determining the island's species richness.
Think of it like a bathtub: Immigration is the water coming in, and extinction is the water going out. The water level (species richness) stabilizes when the inflow and outflow are balanced.
#The Role of Island Size and Distance
Island size and distance from the mainland are HUGE factors in determining species richness.
- Larger Islands:
- Have more habitats and resources.
- Support larger populations, which are less prone to extinction.
- Higher immigration rates because they are easier to spot.
- Islands Closer to the Mainland:
- Easier for species to reach, leading to higher immigration rates.
Larger islands closer to the mainland = more species! Smaller islands farther away = fewer species.
#Visualizing the Theory
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