Species Richness and Diversity Factors

Lecture 23 explores the diversity of communities, starting with a comparison of rank abundance curves for a mountain stream and a coastal pond, highlighting differences in species richness and evenness. The lecture delves into patterns of diversity across latitudes, noting the higher diversity in tropical regions compared to temperate and boreal systems. Various factors affecting diversity, such as abiotic and biotic interactions, random chance, and historical contingencies, are discussed. The lecture also examines the relationship between habitat size and species diversity, using examples from islands and continents, and suggests that larger areas support more diverse communities.

Which community has higher species richness according to the lecture?

• Tropical rainforest

• Mountain stream

• Tundra

• Coastal pond

What is a common pattern observed in species richness as latitude increases?

• Species richness remains constant

• Species richness increases

• Species richness decreases

• Species richness fluctuates randomly

Which of the following is NOT mentioned as a factor affecting diversity?

• Abiotic environment

• Biotic interactions

• Genetic mutations

• Random chance

How does habitat size generally affect species diversity?

• Smaller habitats have more species

• Habitat size does not affect species diversity

• Larger habitats have more species

• Larger habitats have fewer species

What is one reason larger islands may have more diverse communities?

• They have more sunlight

• They have larger populations of species

• They have more predators

• They have more rainfall

Which type of area is mentioned as having a similar pattern to islands in terms of species richness?

• Deserts

• Mountain tops

• Urban areas

• Rivers

What is the relationship between continent size and mammal species richness?

• Smaller continents have more species

• Larger continents have fewer species

• Continent size does not affect species richness

• Larger continents have more species

Why might tropical regions have higher diversity according to one hypothesis?

• They have more rainfall

• They have a larger area

• They have more sunlight

• They have more predators

Which of the following systems is mentioned as having a smaller total area compared to the tropics?

• Urban areas

• Deserts

• Temperate systems

• Oceans

What is a potential consequence of larger populations in larger areas?

• Increased extinction risk

• Decreased species diversity

• Increased competition

• Reduced extinction risk