AP Biology Questions on Species Richness and Diversity

📚 Quick Study Guide

• 🌍 Species richness refers to the number of different species represented in an ecological community, landscape, or region. It's a simple count.
• 🌱 Species diversity takes into account both the number of species and their relative abundance. A community with more species that are evenly distributed is more diverse.
• 🔢 Simpson's Diversity Index ($D$) is often used to quantify biodiversity. It represents the probability that two individuals randomly selected from a sample will belong to the same species. The formula is: $D = \sum (p_i)^2$, where $p_i$ is the proportion of individuals in the $i$th species.
• 📊 Simpson's Index of Diversity ($1 - D$) is also commonly used. It represents the probability that two individuals randomly selected from a sample will belong to different species.
• 🔑 A higher Simpson's Index of Diversity indicates greater diversity.
• 🔬 Factors affecting species richness and diversity include: latitude (generally higher diversity near the equator), habitat size, environmental conditions, and evolutionary history.
• 💡 Conservation efforts often focus on maintaining or increasing species richness and diversity to promote ecosystem stability and resilience.

🧪 Practice Quiz

1. Which of the following best describes species richness?
   1. The relative abundance of different species in a community.
   2. The number of different species in a community.
   3. The genetic variation within a single species.
   4. The interactions between different species in a community.
2. Which of the following indices accounts for both the number of species and their relative abundance?
   1. Species richness
   2. Simpson's Diversity Index
   3. Population density
   4. Carrying capacity
3. A forest community contains 5 species of trees. Species A has 70 individuals, while species B, C, D, and E each have 10 individuals. What can be said about the diversity of this community?
   1. It has high species richness and high diversity.
   2. It has high species richness but low diversity.
   3. It has low species richness and high diversity.
   4. It has low species richness and low diversity.
4. Which of the following factors typically leads to higher species richness?
   1. Extreme environmental conditions
   2. Small habitat size
   3. High latitude
   4. Habitat heterogeneity
5. What does a high Simpson's Index of Diversity suggest about a community?
   1. Low species evenness
   2. High dominance by one species
   3. High species evenness
   4. Low species richness
6. Which of the following is the most direct consequence of reduced species diversity in an ecosystem?
   1. Increased ecosystem stability
   2. Decreased ecosystem resilience to environmental changes
   3. Increased primary productivity
   4. Enhanced nutrient cycling
7. In the context of island biogeography, which island would likely exhibit the highest species richness?
   1. A small island far from the mainland
   2. A large island far from the mainland
   3. A small island near the mainland
   4. A large island near the mainland