Question

scenario:
you are a field biologist observing a small island where a species of finch live. over the past 15 years, climate change has altered the islands vegetation, affecting the availability of food. youre tasked with analyzing how the finch population has evolved and predicting future evolutionary trends.

part a: natural selection in action (sc.912. l.15.13)

1. define the four conditions necessary for natural selection. fill in the chart with definitions and use the evidence from the finch scenario found in the galapagos islands

condition	definition	evidence from scenario
2. inherited variation
3. struggle for survival
4. differential reproductive success

1. use the information above to construct an explanation of how natural selection may change beak size in the finch population over the next 10 years.

part b: other mechanisms of evolution (sc.912. l.15.14)
you learn that a storm carried a small group of finches to another nearby island, and those birds later returned and began mating with the original population.

1. identify which mechanism of evolution this describes:

• □ genetic drift
• □ gene flow
• □ nonrandom mating

1. explain how this mechanism could change the population over time.

part c: mutation and recombination (sc.912. l.15.15)
a rare mutation caused a few finches to develop a curved beak, which helps them open a new kind of seed.

1. explain how this mutation can lead to an increase in genetic variation.
2. predict what might happen to the curved beak trait if the new seed becomes the most available food source.

Explanation:

Part A:

1.

Condition	Definition	Evidence from Scenario
2. Inherited variation	Traits passed between generations	Finches have genetically distinct beak sizes/shapes present in the population.
3. Struggle for survival	Competition for limited resources	Climate change reduced vegetation, so finches compete for scarce food sources.
4. Differential reproductive success	Trait-linked survival/reproduction advantage	Finches with beaks matching available seeds survive longer and produce more offspring.

2.

Assuming climate change continues reducing small, soft seeds and favoring large, hard seeds (or vice versa): finches with beaks suited to the dominant available seed type will survive the struggle for food, reproduce more successfully, and pass their beak trait to offspring. Over 10 years, the population's average beak size will shift toward the advantageous trait.

The scenario describes movement of individuals between populations and interbreeding, which is the definition of gene flow.

Gene flow transfers genetic material between populations, altering the original population's allele frequencies.

Answer:

If the most available food becomes large, hard seeds, the average beak size in the finch population will increase over 10 years. Finches with larger, stronger beaks will better access food, survive longer, and produce more offspring that inherit this trait. If small, soft seeds become dominant, average beak size will decrease as smaller-beaked finches have greater reproductive success.

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Part B:

1.