Gene flow & mutation
Mechanisms
Case studies
Interpret the figure
Natural Selection & Genetic Drift
100
These are the only way new alleles can be created.
What are mutations?
100
The change in allele frequencies over time.
What is evolution?
100
Some species of clover developed a mutation that caused cyanide to form in the plant's cells. This gave the clover a bitter taste, making it less likely to be eaten. However, when the temperature drops below freezing, some cells rupture, releasing the cyanide into the plant's tissues and killing the plant. Where will this mutation be beneficial?
In warm environments.
100
What mechanism is depicted in this figure?
Genetic drift.
100
TRUE or FALSE: genetic drift occurs by chance.
True
200
Dominant alpha wolves lead their pack in Yellowstone National Park while the lowest ranking omega individual may eventually leave the pack to find a mate and establish his own territory and pack. What mechanism of evolution does this represent?
What is gene flow?
200
The mechanism of evolution that is adaptive.
What is natural selection?
200
What mechanism of evolution is shown here?
What is artificial selection?
200
Trees turned dark during the Industrial Revolution due to soot deposits. What mechanism of evolution is depicted here?
What is natural selection?
200
True/False: Genetic drift can occur in both large and small populations.
True
300
True or false: Frequent movement of individuals and/or alleles between populations makes the two populations more likely to speciate (form new species).
False.
300
Also termed "survival of the fittest".
What is natural selection?
300
Due to hunting, the population of Northern elephant seals was reduced to 20 individuals at the end of the 19th century. Since then, their population has rebounded to over 30,000.
What is the long-term effect of hunting on the genetic variation of the elephant seal population?
Individuals are genetically similar to one another.
300
Wild boars were introduced to an island. Which type of selection did the cacti exhibit after this occurred? 
What is directional selection?
300
Which selection type is this?
Disruptive selection
400
True or false: mutations are detrimental and will denature proteins.
False (not always!).
400
The gain or loss of alleles in a population due to the movement of individuals or gametes.
What is gene flow?
400
African elephants are poached for their tusks (ivory). Elephants with large tusks are preferentially hunted. Elephants with no tusks are 'unfit' since they cannot dig or attract mates without tusks. Which tusk size will be selected for over time and why?
Medium tusks via stabilizing selection for an intermediate trait value.
400
What mechanism is shown here?
What is natural selection?
400
In some wild cats, having too short or too long of a tail can disrupt the balance of the animal. Medium tails are selected for. Which type of selection is this?
Stabilizing selection
500
Habitat destruction can lead to habitat fragmentation. How does this impact gene flow?
Gene flow will decrease in fragmented areas and could lead to the speciation of fragmented populations.
500
A mechanism of evolution.
What is genetic drift?
500
As the Grand Canyon was being formed by the Colorado River, this species of squirrel was separated geographically north and south of the canyon. The two populations no longer had gene flow between them and this led to what?
Speciation.
500
What phenomenon is depicted here?
Phenotypic plasticity and acclimatization.
500
A population of birds lives on an island where seeds are their primary food source. Birds with smaller beaks can eat small seeds more easily and birds with larger beaks can eat both small and large seeds.
A fungus destroys the plants that make small seeds, leaving only the large seeds as food.
What selection type is likely to happen?
What is directional selection?