Question

The splitting of one species into two or more species is called a. speciation. b. macroevolution. c. common descent. d. adaptation.

Short answer

a. speciation

Step-by-step solution

Understanding the Concept

The exercise asks for the term that refers to the process by which one species splits into two or more distinct species. Let's examine each option to understand which one fits.

Option a: Speciation

Speciation is the correct term that refers to the evolutionary process by which populations evolve to become distinct species. It directly addresses the splitting of one species into two or more species.

Option b: Macroevolution

Macroevolution refers to large-scale evolutionary changes that occur over long periods, often resulting in new species, but it does not specifically denote the splitting of one species into two or more.

Option c: Common Descent

Common descent is the concept that all living organisms share a common ancestor. While it relates to evolutionary theory, it does not describe the process of splitting into new species.

Option d: Adaptation

Adaptation refers to the process by which a species becomes better suited to its environment. It does not describe the splitting of one species into multiple species.

Conclusion

Based on the definitions, option a (Speciation) is the correct answer as it specifically describes the splitting of one species into two or more species.

Key concepts

macroevolution

Macroevolution refers to large-scale evolutionary changes that occur over long periods. These changes often result in the emergence of new species, new genera, families, and higher taxonomic categories. Unlike microevolution, which involves small changes within a species, macroevolution encompasses more significant and complex changes. For example, the evolution of mammals from reptilian ancestors is a macroevolutionary process.
These evolutionary shifts can be driven by a variety of factors including:

• Natural selection
• Genetic drift
• Mutations
• Migrations

While speciation is a part of macroevolution, macroevolution also includes broader patterns such as the rise and fall of dominant groups (like dinosaurs), and major shifts in earth’s biodiversity over geological time scales.

common descent

Common descent is the principle that all living organisms share a single common ancestor. This means that if you trace back far enough, you will find a universal common ancestor from which all life descended. This idea is a cornerstone of evolutionary biology and is supported by various lines of evidence including:

• Fossil records
• Comparative anatomy
• Genetic similarities
• Molecular biology

For instance, the similarities in DNA sequences between humans and chimpanzees suggest a close common ancestor. Common descent explains the shared characteristics among diverse species and highlights the unity of life. It portrays evolution as a tree with a single trunk and many branches, representing the various life forms.

adaptation

Adaptation is the process by which a species becomes better suited to its environment. Through natural selection, traits that enhance survival and reproduction become more common in a population over generations. For example, the thick fur of Arctic foxes is an adaptation to cold climates.
Adaptations can be:

• Structural: Physical features like the beak shape of birds.
• Behavioral: Actions like bird migration.
• Physiological: Internal functions like the venom production in snakes.

Adaptation plays a critical role in how species evolve over time and can lead to speciation when a population's adaptations cause it to diverge significantly from other populations. Understanding adaptation helps us grasp how organisms develop specialized features and how biodiversity arises.