Answer:
Researchers might choose to use molecular data, such as ribosomal RNA (rRNA) sequences, instead of morphological data to study the evolutionary history of animals due to several reasons:
Genetic Similarities: Molecular data provides insights into the genetic similarities and differences between organisms. By analyzing rRNA sequences, researchers can compare the genetic makeup of different species and determine their evolutionary relationships. This approach allows for a more objective and quantitative assessment of evolutionary history, as genetic sequences are less influenced by subjective interpretations of morphological features.
Hidden Variation: Morphological features can be influenced by various factors such as environmental conditions, convergent evolution, or genetic plasticity. In contrast, molecular data can reveal hidden genetic variation that might not be apparent based solely on physical characteristics. This hidden variation can provide a more accurate depiction of evolutionary relationships and patterns.
Rapid Evolutionary Changes: Some evolutionary changes occur at the molecular level, such as changes in DNA sequences or gene expression, that may not be immediately reflected in morphological characteristics. Molecular data can capture these rapid evolutionary changes more effectively, allowing researchers to explore finer-scale evolutionary events and understand the timing and mechanisms behind them.
Resolving Complex Relationships: In some cases, species may exhibit similar morphological traits due to convergent evolution or evolutionary convergence, making it challenging to determine their true evolutionary relationships based on morphology alone. Molecular data, on the other hand, can reveal underlying genetic differences and provide a clearer understanding of the evolutionary connections between species.
Overcoming Fossil Limitations: Fossil records may be incomplete or unavailable for many species, making it difficult to study their evolutionary history solely through morphological data. Molecular data allows researchers to examine the genetic relationships between extant species, providing valuable insights into their evolutionary past even in the absence of fossil evidence.
Step-by-step explanation:
Overall, molecular data offers several advantages in studying the evolutionary history of animals, including the ability to assess genetic similarities, uncover hidden variation, capture rapid evolutionary changes, resolve complex relationships, and overcome limitations of fossil records. These factors contribute to a more comprehensive and accurate understanding of the evolutionary processes that have shaped the animal kingdom.