Over one survey interval, an island gains as many species through immigration as it loses through local extinction. No other process changes its species count. Comparing the start and end of that interval, what can happen?

• Richness can remain stable while species identities change
• Richness can fall as species identities change
• Richness can rise when arriving species accumulate faster than losses

What does a physiological tolerance range describe?

• Distance travelled during migration
• Locations where a species occurs
• Conditions an organism can withstand

A narrow tolerance for one environmental factor guarantees a small geographic range.

Circle one:   True   False

In a permitted study, introduced organisms survive and reproduce beyond their recorded range. Habitat and competitors were unchanged. What does this support?

• Competition is supported as the cause of absence
• A newly evolved tolerance explains establishment beyond the previous range
• Blocked arrival is supported as a possible cause of absence

Which set covers distinct kinds of limits on a species' range, rather than several examples of one kind?

• Temperature, salinity and oxygen tolerance
• Unsuitable conditions, blocked arrival or interactions
• Competition, predation and disease within an established community

An illustrative species-area model predicts 60 species initially. Area becomes 1/4 of its original value. With illustrative z = 0.5 and unchanged model constants, how many species does it predict?

Answer: ______________

A species-area model predicts lower richness after habitat loss. Which interpretation is justified?

• It estimates the losses already observed
• It is an estimate under the model's assumptions
• It estimates extinctions worldwide

A population's vital rates remain stable through warmer years. Why is this not proof of genetic adaptation?

• Stable vital rates do not establish an inherited change
• Adaptation may await further warming
• The population may need to shift its range before adaptation can occur