Which best illustrates a result of natural selection?

December 12, 2024

Question: Which best illustrates a result of natural selection?

A. A bat that is born with a wing that is missing the web
B. Dark-colored hares living in a snowy area
C. Mosquitoes that transmit disease to humans
D. Giraffes having increasingly longer necks over time

Answer: D. Giraffes having increasingly longer necks over time

Explanation:

Step1: Understanding Natural Selection

Natural selection is a fundamental mechanism of evolution proposed by Charles Darwin. It explains how traits that enhance an organism's survival and reproductive success become more common in successive generations of a population. The key components of natural selection include:

Variation: Differences exist among individuals in a population.
Inheritance: Traits can be passed from parents to offspring.
Differential Survival and Reproduction: Individuals with advantageous traits are more likely to survive and reproduce, passing those traits to the next generation.

Step2: Evaluating Each Option

Option A: A bat that is born with a wing that is missing the web
Analysis: This scenario describes a congenital defect or mutation. Such a trait is typically disadvantageous and does not enhance the bat's survival or reproductive success. Therefore, it is not a result of natural selection favoring an advantageous trait.
Option B: Dark-colored hares living in a snowy area
Analysis: In a snowy environment, lighter-colored hares have better camouflage against predators. Dark-colored hares would be more visible, making them more susceptible to predation. This trait would likely be selected against, not favored by natural selection.
Option C: Mosquitoes that transmit disease to humans
Analysis: While the ability to transmit disease is significant, it pertains more to the mosquito's role as a disease vector rather than a direct morphological or behavioral trait resulting from natural selection. This trait involves complex interactions and may not directly illustrate natural selection in the same clear-cut manner as other options.
Option D: Giraffes having increasingly longer necks over time
Analysis: This is a classic example of natural selection. Longer necks allow giraffes to access food sources (leaves) that are out of reach for other herbivores. This gives them a competitive advantage in environments where food resources are limited to higher foliage. As a result, giraffes with longer necks are more likely to survive and reproduce, passing on the trait to future generations.

Extended Knowledge:

Natural Selection and Adaptation

Natural selection leads to adaptations, which are traits that improve an organism's ability to survive and reproduce in its environment. Over time, these adaptations become more prevalent within the population.

Example: Giraffes' Long Necks

The evolution of the giraffe's long neck is an adaptation that allows access to high foliage, reducing competition for food with other herbivores. This trait enhances survival during times when lower vegetation is scarce, ensuring that giraffes with longer necks have a better chance of thriving and passing on their genes.

Contrast with Other Options

Congenital Defects (Option A): Traits that hinder survival are typically weeded out through natural selection, reducing their prevalence in the population.
Camouflage and Predation (Option B): Traits that enhance camouflage improve survival rates, whereas those that diminish it (like darker coloration in snowy areas) are selected against.
Ecological Roles (Option C): While important, the role of mosquitoes in disease transmission involves multiple factors beyond straightforward natural selection, such as environmental changes and human interventions.

Misconceptions about Natural Selection

Survival of the Fittest: "Fittest" refers to those best adapted to their environment, not necessarily the strongest or fastest.
Natural Selection vs. Artificial Selection: Natural selection occurs without human intervention, whereas artificial selection involves humans breeding organisms for desired traits.

Importance of Natural Selection in Evolution

Natural selection drives the diversity of life by promoting traits that enhance survival and reproductive success. It is a continuous process that responds to environmental changes, ensuring that populations remain adaptable and resilient.

Practical Implications

Understanding natural selection helps in various fields such as medicine (e.g., antibiotic resistance), conservation biology (e.g., preserving endangered species), and agriculture (e.g., developing pest-resistant crops).

Conclusion

D. Giraffes having increasingly longer necks over time best illustrates a result of natural selection. This example clearly demonstrates how advantageous traits become more prevalent within a population, enhancing the organisms' ability to survive and reproduce in their specific environment.

Question 1: Which of the following is an example of natural selection in action?

A. A population of rabbits where faster individuals are more likely to escape predators
B. A tree that grows taller over time due to increased sunlight
C. A species of fish that changes color due to water pollution
D. A group of birds that learns to use tools to obtain food

Answer: A. A population of rabbits where faster individuals are more likely to escape predators

Brief Explanations:

Natural selection occurs when certain traits increase an organism's ability to survive and reproduce in a given environment. In this case, faster rabbits are more likely to escape predators and pass on their genes to future generations.

Question 2: What is a primary factor that drives natural selection?

A. Random mutations that occur in DNA
B. The availability of food sources
C. The ability of organisms to adapt to their environment
D. The presence of predators in an ecosystem

Answer: C. The ability of organisms to adapt to their environment

Brief Explanations:

Natural selection is driven by an organism's ability to survive and reproduce based on its traits. Adaptations that help organisms survive in their environment are favored, leading to changes in the population over time.

Question 3: Which scenario best illustrates the concept of adaptation through natural selection?

A. A lizard changes color to blend in with its environment over a few generations
B. A bear grows larger due to a plentiful food supply
C. A plant develops deeper roots when planted in sandy soil
D. An animal learns to avoid certain areas where predators are present

Answer: A. A lizard changes color to blend in with its environment over a few generations

Brief Explanations:

Adaptation through natural selection occurs over generations, where beneficial traits, like color changes in the lizard, increase survival and reproduction chances. Traits that help an organism blend into its environment are more likely to be passed down.

Question 4: Which statement about natural selection is TRUE?

A. Natural selection can only occur in large populations
B. Natural selection leads to the evolution of new species immediately
C. Natural selection favors traits that enhance survival and reproduction
D. Natural selection guarantees that all individuals in a population will survive

Answer: C. Natural selection favors traits that enhance survival and reproduction

Brief Explanations:

Natural selection favors traits that increase an organism's ability to survive and reproduce in its environment. It does not guarantee the survival of all individuals or lead to immediate new species.