Levels of Biodiversity
What are the three levels of biodiversity?
Genetic diversity, species diversity, and ecosystem diversity.
What are ecosystem services?
Benefits humans obtain from natural ecosystems.
What does the Theory of Island Biogeography explain?
Patterns of species richness based on island size and distance from mainland.
Define adaptation.
A trait that improves an organism’s ability to survive and reproduce in its environment.
Define ecological succession.
Gradual change in species composition of an ecosystem over time.
Which level of biodiversity allows species to better resist disease or environmental change?
Genetic diversity.
Give one example of a provisioning service.
Food, timber, fresh water, or medicine.
How does island size affect species richness?
Larger islands have more habitats and lower extinction rates.
What is the range of tolerance?
Range of conditions (e.g., temperature, pH) a species can endure before injury or death.
Differentiate between primary and secondary succession.
Primary starts on bare rock (no soil); secondary starts where soil already exists.
Explain the difference between species richness and evenness.
Richness = # of species; evenness = relative abundance of each species.
Which type of service includes pollination and soil formation?
Supporting services.
How does distance from the mainland affect species richness?
Closer islands receive more immigrants → greater diversity.
Which zone of tolerance supports the most growth and reproduction?
The optimal range.
What are pioneer species and give an example.
First colonizers in succession (e.g., lichen, moss).
Why does high biodiversity increase ecosystem resilience?
More species → functional redundancy → ecosystem can recover from disturbances.
Explain how deforestation reduces a regulating service.
Trees no longer store CO₂ or filter air → increased climate change and pollution.
What is adaptive radiation and where is it commonly observed?
Rapid speciation from a common ancestor to fill different niches (e.g., Galápagos finches).
Explain how climate change can affect a species’ range of tolerance.
Shifts conditions beyond the optimal range → stress, migration, or die-off.
Describe how biodiversity changes through succession.
Increases over time as new species colonize and form complex communities.
Describe a bottleneck event and its effect on genetic diversity.
A random disturbance reduces population size, decreasing genetic variation and resilience.
Identify a cultural service and how it can be economically valuable.
Recreation or tourism (e.g., park fees, ecotourism jobs).
Explain why small, isolated islands are more vulnerable to extinction.
Smaller populations + less immigration = lower genetic diversity and higher extinction risk.
Why do species with high genetic diversity adapt more quickly to change?
More gene variants → higher chance some individuals survive new conditions.
Identify the characteristics of a climax community.
Stable, mature ecosystem with high biodiversity and efficient nutrient cycling.