Question

Which of the following best explains how natural selection is involved in the evolution of the Arctic fox's thick fur coat? (A) Arctic foxes with thinner coats migrated south for the winter. (B) Arctic foxes with thinner coats did not survive because they were not well-suited to the harsh conditions of their environment. (C) Arctic foxes with thick coats preferred to mate only with other Arctic foxes who had thick fur coats. (D) Arctic foxes with thick fur coats killed off all the Arctic foxes thinner coats.

Short answer

Option B best explains how natural selection is involved in the evolution of the Arctic fox's thick fur coat, as Arctic foxes with thinner coats would be less likely to survive and reproduce in harsh conditions, leading to a gradual increase in the occurrence of thicker fur coats in the Arctic fox population over time.

Step-by-step solution

Understanding Natural Selection

Natural selection is the process by which organisms with advantageous traits that enable them to better survive and reproduce tend to pass on those traits to their offspring, while organisms with less advantageous traits are less likely to survive and reproduce. This results in the gradual evolution of a species over time.

Evaluating Option A

Option A suggests that Arctic foxes with thinner coats migrated south for the winter. While it is possible that some of the foxes with thinner coats may have migrated to a warmer region, this option does not specifically explain how natural selection played a role in the evolution of the thick fur coat.

Evaluating Option B

Option B states that Arctic foxes with thinner coats did not survive because they were not well-suited to the harsh conditions of their environment. This option aligns with the concept of natural selection, as the individuals with a less advantageous trait (a thinner fur coat) would be less likely to survive and reproduce in their harsh environment, while those with thicker fur coats would have a better chance of survival and reproductive success.

Evaluating Option C

Option C proposes that Arctic foxes with thick coats preferred to mate only with other Arctic foxes who had thick fur coats. While this may have been a fact, it would be considered as an element of sexual selection rather than natural selection. Sexual selection could have reinforced the trait; however, it does not relate directly to the survival and reproductive advantage of having a thicker coat in a cold environment.

Evaluating Option D

Option D implies that Arctic foxes with thick fur coats killed off all the Arctic foxes thinner coats. This would be an example of direct competition within a species, not natural selection acting on the advantageous trait of a thick fur coat. Additionally, this reasoning is unlikely as Arctic foxes typically do not pose a direct threat to other foxes of their species.

Identifying the Best Explanation

Out of the presented options, Option B best explains how natural selection is involved in the evolution of the Arctic fox's thick fur coat. Arctic foxes with thinner coats would be less likely to survive and reproduce in harsh conditions, leading to a gradual increase in the occurrence of thicker fur coats in the Arctic fox population over time.

Key concepts

Evolution

Evolution is the gradual change in species over long periods. It's primarily driven by natural selection, where organisms with beneficial traits tend to survive and reproduce at higher rates. Over generations, these advantageous traits become more common in the population. Evolution is not a speedy process. It takes many iterations and generations to see significant changes. Through evolution, species can develop traits that help them survive better in their particular environments.

In the case of the Arctic fox, evolution has led to the development of its thick fur coat, an essential trait for survival in freezing conditions. Evolution is fundamental to understanding how diverse forms of life adapt to their environments, ensuring survival and continuation.

Arctic Fox Adaptation

Adaptations in Arctic foxes illustrate how species can evolve traits perfectly suited for their environments. The Arctic environment is extremely cold, often with temperatures dropping very low, which poses survival challenges. To combat these harsh conditions, the Arctic fox has developed several adaptations.

One primary adaptation is their thick fur coat, offering insulation and maintaining body warmth in freezing temperatures. Their fur is not only dense but often white during winter, serving as camouflage in the snowy landscapes. This helps them evade predators and stealthily approach prey.

• Thick, dense fur for warmth.
• Seasonal coat color change for camouflage.
• Fluffy tail functioning as added insulation.

These adaptations ensure the Arctic fox can thrive in its demanding environment, demonstrating the power of evolutionary processes.

Survival Traits

Survival traits are characteristics that increase an organism's chances of surviving and reproducing in its environment. For the Arctic fox, this includes not only its thick fur but also a high-fat diet that provides essential energy in a cold climate.

The fox's compact body shape minimizes heat loss, an advantageous trait seen in many Arctic mammals. They also have keen hearing adapted to detect prey moving under the snow, ensuring they can find food even in scarce conditions. These are just a few of the survival traits that showcase how natural selection operates. Organisms that possess such beneficial traits are more likely to survive, reproduce, and pass these features on to their offspring.

• High-fat diet for energy.
• Compact body shape to prevent heat loss.
• Acute senses for finding food.

These traits combine to form an effective strategy for life in the severe climate.

Environmental Adaptation

Environmental adaptation refers to the ways organisms adjust to survive in their particular habitats. Adaptation is a vital component of natural selection. It is about fitting into an ecological niche where they can thrive. In the Arctic, the harsh weather demands specific adaptations for survival.

The Arctic fox's thick fur is a prime example, providing the necessary warmth for survival, but adaptation extends beyond just physical traits. Behavioral adaptations, such as storing food during summer, also play a crucial role. In an environment where food is not always available, this behavior ensures they can sustain themselves through long winters.

• Physical adaptations like thick fur.
• Behavioral adaptations such as caching food.
• Seasonal strategies for survival.

These adaptations evolve as a direct response to environmental pressures, demonstrating how finely tuned organisms can become to their surroundings.