Question

What is natural selection? Describe how natural selection might have caused unequal reproduction among the ancestors of a fast-swimming predatory fish, such as the barracuda.

Short answer

Natural selection is the differential survival and reproduction of individuals in a population based on their inherited traits, leading to the evolution of new species over time. In the ancestral population of fast-swimming predatory fish like the barracuda, there would have been natural variations in swimming speed due to genetic differences. Faster-swimming fish would have better access to food resources and increased chances of survival, thus being more successful in reproducing and passing on their advantageous traits. Over many generations, this process would have resulted in the evolution of the barracuda, known for its remarkable speed and predatory prowess.

Step-by-step solution

Define Natural Selection

Natural selection is a fundamental process in evolution. It refers to the differential survival and reproduction of individuals in a population based on their inherited traits. In other words, organisms that inherit traits that better enable them to survive and reproduce in a given environment are more likely to pass on these advantageous traits to their offspring. Over time, this process causes adaptations to accumulate in a population, leading to the evolution of new species.

Describe the Ancestral Environment of the Barracuda

To understand how natural selection led to the evolution of the barracuda, we must first consider the environment where its ancestors lived. These ancestral fish were likely living in aquatic habitats with various other species, including potential prey and competitors. In this environment, the ability to quickly and effectively capture prey would have been a significant advantage in securing food resources.

Explain the Importance of Swimming Speed in Predatory Fish

In predatory fish, swimming speed plays a crucial role in successful hunting and capturing prey. Fast speed allows them to cover greater distances quickly, surprise their prey, and evade other predators or competitors. Therefore, ancestral fish that were faster swimmers would have had a better chance of surviving, successfully capturing prey, and reproducing.

Describe How Natural Selection Led to Unequal Reproduction

In the ancestral population of fish, there would have been natural variations in swimming speed due to genetic differences among individuals. Natural selection would favor those with increased speed since it would provide them with better access to food resources and increased chances of survival. Over time, those faster-swimming fish would be more successful in reproducing and passing on their advantageous traits (such as more efficient muscles or streamlined body shapes) to their offspring. Conversely, slower individuals would be less successful in finding food, have a higher risk of predation, and would be less likely to reproduce.

Explain the Resulting Evolution of the Barracuda

Over many generations, this process - in which faster individuals were more likely to survive and reproduce, leading to the spread of their advantageous traits through the population - would have resulted in the evolution of the barracuda. The barracuda, as a species, would have gradually evolved to become increasingly faster and more efficient in its predatory behavior, thanks to natural selection acting on these traits. This process eventually led to the development of the modern barracuda, which is known for its remarkable speed and predatory prowess.

Key concepts

Evolution

Evolution is the process that transforms the biological features of a species over successive generations. It explains how diverse life forms on Earth have developed from common ancestors through gradual changes. These changes are driven by different mechanisms, including natural selection, mutation, gene flow, and genetic drift.
In natural selection, individuals with traits that provide them with an advantage in their environment tend to survive and reproduce more successfully. These advantageous traits become more common in the population over generations.
This gradual accumulation of traits results in the adaptation and development of new species. For example, as natural selection shape certain traits in predatory fish like barracudas, these species continue to evolve to become more adept at hunting their prey successfully.

Adaptation

Adaptation refers to the process by which a species becomes better suited to its environment through the enhancement of certain traits. These traits are typically characteristics that improve an organism’s ability to survive and reproduce.
In the context of predatory fish like the barracuda, adaptations may include a streamlined body for efficient swimming, acute vision for detecting prey, and sharp teeth for capturing and eating prey.

• Structural Adaptations: These involve physical features of the organism. For barracudas, streamlined bodies reduce water resistance, allowing them to swim faster.
• Behavioral Adaptations: These are actions organisms take to survive, like hunting techniques or migration patterns.
• Physiological Adaptations: These are internal processes that improve survival, such as a fast metabolism to keep energy levels high during pursuit.

Through the process of adaptation, natural selection ensures that only the most beneficial traits persist, enabling the species to thrive in its niche.

Predatory Fish

Predatory fish are aquatic animals that prey on other organisms for food. They play a vital role in maintaining ecological balance by regulating prey populations and providing energy through the food chain.
These fish often exhibit specific adaptations that make them efficient hunters. In the case of barracudas, these adaptations include rapid swimming speeds, strong jaws, and keen eyesight.
Their predatory nature requires them to be highly specialized to catch and consume their prey effectively, which results in morphological and behavioral changes driven by natural selection.

• Speed and Agility: These traits help them surprise and capture their fast-moving prey.
• Cognitive Skills: Enhanced decision-making skills aid in strategic hunting and evasion.

Predatory fish like barracudas have successfully evolved these traits over time to survive in their competitive environments.

Genetic Variation

Genetic variation is a fundamental aspect of biological diversity within and between species. It refers to the differences in DNA sequences among individuals, which lead to variations in traits.
Genetic variation is crucial for the process of natural selection, as it provides the raw material for evolutionary change. Without it, populations cannot adapt to changing environments.
In any given population of fish, different genes may code for variations in swimming speed, size, or coloration. Faster individuals, for example, might possess genetic traits that allow for more efficient muscle function or a finer body shape that reduces drag.

• Source of Variation: Mutations, sexual reproduction, and gene flow all introduce new genetic differences among individuals.
• Role in Adaptation: Variation allows natural selection to favor traits that enhance survival and reproduction in specific environments.

Due to genetic variation, a population of predatory fish like the barracuda can continuously adapt and evolve, ensuring their ongoing success in the wild.