Question

scientists study patterns found in native alpine plant species in an area. they document the species richness per hectare (10,000 square meters) at different elevations historically and recently. species richness is defined as the number of different species in the area.
the scientists attribute the difference between historical and recent species richness to climate change.
which statement supports the scientists conclusion and could explain the data shown in the graph?
a the alpine plant species develop a resistance to effects of the colder conditions.
b the number of diseases targeting alpine plant species increases as a result of increasing temperatures.
c the number of invasive species that compete with the alpine plant species increases as a result of more favorable temperatures.
d the range of alpine plant species shifts to more suitable habitats to meet needs that are lacking as a result of increasing temperatures.

Explanation:

• Option A: If alpine plant species develop resistance to colder conditions, it would not explain the decrease in species richness shown in the graph.
• Option B: An increase in diseases targeting alpine plant species due to increasing temperatures could be a factor, but it is not as comprehensive as the range - shift explanation.
• Option C: An increase in invasive species due to more favorable temperatures is a possible factor, but it does not account for the overall pattern as well as the range - shift.
• Option D: As temperatures increase, the range of alpine plant species shifts to more suitable habitats (higher elevations, for example). This would explain why, at a given elevation, the species richness has decreased (they have moved to other areas), which is consistent with the graph showing lower recent species richness compared to historical at most elevations.

Answer:

D. The range of alpine plant species shifts to more suitable habitats to meet needs that are lacking as a result of increasing temperatures.