Problem 2 - Biology: Concepts and Applications

Question

Stevan Arnold offered slug meat to newborn garter snakes from different populations to test his hypothesis that the snakes' response to slugs ____ a. was shaped by indirect selection b. is an instinctive behavior c. is based on pheromones d. is adaptive

Step-by-Step Solution

Answer

d. is adaptive

Step 1: Identify the Hypothesis

Start by identifying Stevan Arnold's hypothesis. He proposed that the snakes' response to slugs was shaped by natural selection or an evolutionary process.

Step 2: Understand the Options

Analyze what each option suggests. - Indirect selection (a) implies traits are selected not for their direct benefit but due to their relation to other beneficial traits. - Instinctive behavior (b) suggests a genetically inherited response. - Pheromones (c) implies influence by chemical communication. - Adaptive behavior (d) indicates that the response improves survival or reproduction chances.

Step 3: Relate Hypothesis to Options

Determine which option aligns with the given hypothesis. Since the behavior was hypothesized to be shaped by evolutionary processes, which usually promote traits that enhance survival and reproduction, option (d) stands out.

Step 4: Elimination Method

Exclude options that do not fit the hypothesis context: - (c) is irrelevant since it focuses on chemical signals, not evolutionary traits. - (a) is plausible but indirect selection is more specific than general adaptation. - (b) suggests inborn behavior but does not address evolutionary advantage.

Step 5: Select the Best Fit

Choose option (d) as 'adaptive' because it aligns with the hypothesis that the snakes' response is evolutionarily advantageous.

Key Concepts

Evolutionary Biology

Evolutionary biology is the study of how living organisms change over time due to genetic variations and environmental pressures. It explores how species adapt, evolve, and sometimes go extinct. A core aspect of evolutionary biology is understanding why certain traits become more common within a population while others fade away. This branch of biology looks at the big picture of life's development on Earth.

• Genetic Variation: Evolutionary biology examines how differences in DNA among individuals create variations in traits such as color, size, and behavior.
• Environmental Pressures: These are challenges or changes in an organism's surroundings that force species to adapt or risk extinction.
• Adaptation: This occurs when beneficial traits become prevalent within a population, enhancing survival and reproduction. For example, the ability of garter snakes to respond to slugs is a behavioral trait likely influenced by evolutionary pressures.

Understanding these principles provides insights into the diverse forms of life and their interconnections.

Natural Selection

Natural selection is a fundamental mechanism in evolutionary biology. It describes the process where individuals with beneficial traits are more likely to survive and reproduce than those without. Over time, these traits become more common in the population, leading to evolution.
One key concept is "survival of the fittest," which means that the organisms best suited to their environment are more likely to survive. This doesn't necessarily mean the strongest survive, but the most adaptable do.
Garter snakes' inclination towards consuming slugs can be seen as an outcome of natural selection. If the consumption of slugs offered a nutritional advantage or allowed the snakes to thrive in their habitat, those snakes that instinctively went for slugs were more likely to survive and pass on those instincts.
Natural selection operates through several stages:

• Variation: Individuals vary in their traits, some of which are heritable.
• Competition: There is a struggle for resources among organisms within a habitat.
• Selection: Traits providing advantages become more common.
• Inheritance: Advantageous traits are passed down to future generations.

Instinctive Behavior

Instinctive behavior refers to the actions and responses that are innate and inherited rather than learned. These behaviors occur naturally and automatically in animals, aiding their survival and reproduction without needing prior experience or training.
For garter snakes, their potential reflex to consume slugs could be considered instinctive if it is a behavior coded in their genetics rather than one learned or developed through external influences. Instinctive behaviors are significant in the context of survival because they often provide quick, reliable responses to environmental stimuli.
Characteristics of instinctive behavior include:

• Genetic Basis: These behaviors are programmed into an animal’s genes, ensuring they are passed from one generation to the next.
• Stimulus-Specific: Instinctive actions often require specific triggers, such as a smell or sight, to be activated.
• Species-Specific: Many instinctive behaviors are unique to a species, developed over millions of years of evolution.
• Immediate Action: These behaviors typically require no deliberation, allowing an instant response critical for survival.

Instincts play a crucial role in the animal kingdom's functionality, adhering strictly to the survival and reproductive needs of each species.