In the Chiricahua Mountains in Arizona, a Species of Spider

question 32

Multiple Choice

In the Chiricahua Mountains in Arizona, a species of spider is found in both the woodland areas around streams and in the desert shrub areas. In the woodland areas, these spiders are under constant threat of predation from birds. Because of this, they spend little time in the exposed portion of their sheet webs. However, in the desert areas where birds are less of a threat, spiders constantly forage in the exposed portion of their webs. Offspring of matings between spiders from woodland and desert regions behave more like spiders from the desert habitat, even if they are living in the woodland area. The offspring quickly fall prey to birds, often before they have had a chance to reproduce. Over time, two different species arise. What type of reproductive barrier led to this speciation event?

• A) reproductive
• B) geographical
• C) temporal
• D) mechanical

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Definitions:

Infectious Agents

Organisms such as viruses, bacteria, fungi, and parasites that can cause disease in their host.

DNA Sequence

The precise order of nucleotides within a DNA molecule, determining the genetic information carried by an organism.

Mutation

A change in the DNA sequence, which can result in new traits or variations within a population and contribute to the evolution of species.

Inherited

Traits or properties passed down from parents to their offspring through genes.