Question

Recently discovered fossil evidence casts doubt on the evolutionary theory that dinosaurs are more closely related to reptiles than to other classes of animals. Fossils show that some dinosaurs had hollow bones a feature found today only in warm-blooded creatures, such as birds, that have a high metabolic rate. Dinosaurs had well-developed senses of sight and hearing, which is not true of present-day cold-blooded creatures like reptiles. The highly arched mouth roof of some dinosaurs would have permitted them to breathe while eating, as fast-breathing animals, such as birds, need to do. Today, all fast-breathing animals are warm-blooded. Finally, fossils reveal that many dinosaurs had a pattern of growth typical of warmblooded animals. The argument in the passage proceeds by (A) attempting to justify one position by demonstrating that an opposing position is based on erroneous information (B) establishing a general principle that it then uses to draw a conclusion about a particular case (C) dismissing a claim made about the present on the basis of historical evidence (D) assuming that if all members of a category have a certain property then all things with that property belong to the category (E) presenting evidence that a past phenomenon is more similar to one rather than the other of two present-day phenomena

Short answer

(E) presenting evidence that a past phenomenon is more similar to one rather than the other of two present-day phenomena.

Step-by-step solution

Understanding Argument Structure

The passage provides evidence that suggests dinosaurs may not be more closely related to reptiles but rather to warm-blooded animals like birds. It mentions hollow bones, well-developed senses, breathing patterns, and growth patterns typical of warm-blooded animals. This suggests a reevaluation of the classification of dinosaurs.

Evaluating the Argument Options

Analyze each option to understand how the argument is being presented: - Option (A) suggests justifying a position by showing another position is incorrect, but the passage doesn't explicitly demonstrate errors of the opposing view. - Option (B) involves stating a general principle to apply to a specific case, which doesn't match the passage's approach. - Option (C) involves dismissing present claims with historical evidence, which isn't the core tactic used. - Option (D) suggests an assumption that common properties indicate complete category inclusion, which is not how the passage argues. - Option (E) suggests drawing similarities between past phenomena and one of two present possibilities, aligning closely with how the passage presents evidence.

Selecting the Best Argument Option

The passage presents evidence to show that dinosaurs share several characteristics with warm-blooded creatures rather than cold-blooded reptiles. Therefore, the passage attempts to draw similarities between past dinosaurs and present-day warm-blooded animals rather than cold-blooded reptiles.

Key concepts

Evolutionary Theory

Evolutionary theory is essentially the framework that explains how species change over time through various processes like natural selection, mutation, and genetic drift. It is rooted in the idea that all species are connected through common ancestry, leading to new species diversifying from one another over geological timescales.

In the context of the exercise, we explore how new fossil evidence introduces the need to possibly rethink the evolutionary relationship between dinosaurs and other animals. Traditionally, dinosaurs have been considered more closely related to reptiles. However, findings such as hollow bones and other warm-blooded characteristics open up debates about their classification.

• Natural selection: Process where traits that enhance survival and reproduction become more common in successive generations.
• Phylogenetics: Study of evolutionary relationships, essential for understanding classifications.

By examining evolutionary theory, scientists not only understand past life forms but can also track how modern species have evolved over time.

Fossil Evidence

Fossils are remnants or impressions of ancient organisms preserved in rock, giving us a glimpse into Earth's biological past. They offer physical evidence that supports or challenges existing evolutionary theories. In this exercise, fossil evidence has become a crucial factor in reconsidering the relationship between dinosaurs and reptiles.

These fossils reveal characteristics such as hollow bones and unique growth patterns that hint at warm-blooded properties. Such features are significant because they are uncommon among modern reptiles but are present in birds, suggesting a closer relationship with avian species.

• Preservation: Fossils are typically formed in sedimentary rock layers over millions of years.
• Types: Body fossils (bones, shells) and trace fossils (footprints, burrows).

Fossil evidence often serves as a key tool in piecing together the evolutionary history of extinct species and understanding their connections to living organisms.

Warm-Blooded Animals

Warm-blooded animals, also known as endotherms, maintain a stable internal body temperature regardless of external conditions. This physiological trait allows for high metabolic rates and sustained activity in cold environments, typical in birds and mammals.

In relation to dinosaurs, the discovery of characteristics often associated with warm-blooded animals triggers a reevaluation of their metabolic classification. Such traits include their capacity for fast breathing and evidence of an arched mouth roof similar to modern fast-breathing birds.

• Metabolic rate: Endotherms have a high metabolism to support active lifestyles.
• Temperature regulation: They have mechanisms to retain heat, ensuring vital physiological processes continue without disruption.

This raises fascinating questions about how dinosaurs may have thrived, perhaps indicating a more bird-like existence than previously assumed.

Reptile Classification

Reptile classification refers to understanding how various reptiles are categorized based on shared characteristics. Traditional classifications have positioned dinosaurs within the broader category of reptiles due to shared features like scaly skin and certain bone structures.

However, the new fossil evidence challenges this traditional view by presenting traits commonly found in warm-blooded animals. This requires scientists to reconsider how they classify dinosaurs, as they share a number of physiological traits with birds and mammals.

• Characteristics: Cold-blooded, scaly skin, and primarily lay eggs.
• Modern examples include lizards, snakes, crocodiles, and turtles.

This classification debate highlights the fluid nature of scientific understanding and the importance of continuously revising our theories in light of new evidence.