Question

4. During a drought, you discover that finches with large beaks and those with small beaks were more successful due to the food sources available during the drought. Which model of selection is occurring, and how do you know?

Which model of selection is occurring, and how do you know?

Group of answer choices

Disruptive selection, because both extreme phenotypes exhibited higher fitness.

Sexual selection, because beak size is correlated to mating success.

Stabilizing selection, because multiple phenotypes experienced higher fitness retaining their presence in the population.

Directional selection, because only extreme phenotypes are favored in this scenario.

Imagine you observe two species. Both species share a similar feature, and you are trying to decide if the feature is homologous or the result of convergent evolution. What is the BEST strategy to use?

Group of answer choices

Determine if the feature is shared with a third species.

Determine if the feature is vestigial.

Determine if the species' common ancestor also had this feature.

Determine if the feature is used for the same purpose in the two species.

Answer 1

4.

Disruptive selection, because both extreme phenotypes exhibited higher fitness.

Natural selection is process in which individual organisms or phenotypes that possess favorable traits are more likely to survive and reproduce.

Types of natural selection are stabilizing, directional, and diversifying selection or disruptive selection.

Disruptive selection is the rarest of these three types of natural selection. In disruptive selection, two or more extreme phenotypes are selected for, while the average phenotype is selected against. Over time, the two extreme variations will become more common and the intermediate states will be less common or lost. Disruptive selection can lead to two new species. Here in drought, it was discovered that finches with large beaks and those with small beaks were more successful.

All other choices are wrong related with the scenario

Sexual selection, because beak size is correlated to mating success. No relation ship between beak size and sexual selection

Stabilizing selection, because multiple phenotypes experienced higher fitness retaining their presence in the population. In the scenario two extremes of phenotypes ( short and long) naturally selected.

Directional selection also wrong, because only extreme phenotypes are favored in this scenario.

Answer: Determine if the feature is used for the same purpose in the two species

Convergent evolution

Convergent evolution is the process in which organisms that are not closely related independently evolve similar features. The word “analogous” is used to describe such structures of two evolutionary unrelated species and yet they have similar or corresponding functions.

Eg: Although very different species, the dolphin(mammal) , icthyasaur ( reptile), and shark ( cartilaginous fish) are look alike. All these have evolved a shape that moves through water with minimum of resistance, hence their superficial similarities.