What becomes more likely to occur in a small population? Check all that apply.

Question

_____  the Allee effect
_____  increased genetic drift
_____  increased genetic diversity
_____  extinction vortex
_____  increased edge effect

Additional:
Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?

Gather Content
· What do you already know about population size?

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

__X__  the Allee effect
__X__  increased genetic drift
_____  increased genetic diversity
__X__  extinction vortex
_____  increased edge effect

Clarify Question

· What is the key concept addressed by the question?
        o This question addresses population size.
· What type of thinking is required?
        o This question is asking you to analyze the information given, using logic, to dissect the problem and determine the answer.
 
Gather Content

· What do you already know about population size?
        o As populations decrease in size, demographic and genetic factors combine to cause what has been termed an “extinction vortex.”
        o As it gets smaller, it becomes more vulnerable to demographic catastrophes. Genetic variation is lost, causing re productive rates to decline and population numbers to decline even further. Eventually, the population disappears entirely, but attributing its demise to one particular factor would be misleading.
        o When populations become extremely small, bad luck can spell the end. For example, the dusky seaside sparrow dwindled to a population of five individuals, all of which happened to be males. In a large population, the probability that all individuals will be of one sex is infinitesimal. But in small populations, just by the luck of the draw, it is possible that 5 or 10 or even 20 consecutive births will all be individuals of one sex, and that can be enough to send a species to extinction. In addition, when populations are small, individuals may have trouble finding each other (the Allee effect), thus leading the population into a downward spiral toward extinction.
 
Choose Answer

· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o A small population will suffer from: the Allee effect (individuals have trouble finding mates), increased genetic drift, decreased genetic diversity, and possibly an extinction vortex as these different factors synergize.
 
Reflect on Process

· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o The question required you to analyze the information given, using logic, to dissect the problem and determine the answer.
        o Did you recognize that small populations suffer in several ways, as lower genetic diversity increases genetic drift, and they have trouble finding mates as well?