In vertical evolution, new species evolve from pre-existing species by accumulation of:

• A. genetic mutations
• B. behavioral adaptations only
• C. environmental changes
• D. horizontal gene transfers

Answer: (A)

Verified step by step guidance

1. Understand the concept of vertical evolution: Vertical evolution refers to the process by which new species arise from pre-existing species over time through gradual changes in their genetic makeup.
2. Recognize the role of genetic mutations: Genetic mutations are changes in the DNA sequence that can introduce new traits or variations within a population. These mutations accumulate over generations and contribute to the evolution of new species.
3. Differentiate between genetic mutations and other factors: While behavioral adaptations, environmental changes, and horizontal gene transfers can influence evolution, vertical evolution specifically emphasizes the accumulation of genetic mutations as the primary mechanism.
4. Consider examples of vertical evolution: For instance, the gradual changes in the fin structure of fish leading to the evolution of amphibians demonstrate how genetic mutations accumulate over time to create new species.
5. Review the options provided: Based on the definition of vertical evolution, identify that the correct answer is 'genetic mutations,' as they are the key factor driving this process.