Question

Vestigial structures, homologous structures, and biochemical similarities all provide evidence of: a. descent from a common ancestor b. barriers to migration c. random mating d. sexual selection

Short answer

a. descent from a common ancestor

Step-by-step solution

Define Vestigial Structures

Vestigial structures are anatomical features that no longer serve a purpose in the current form of an organism but were functional in ancestral species. Examples include the human appendix and the pelvic bones in whales.

Define Homologous Structures

Homologous structures are anatomical features in different species that are similar due to common ancestry. These structures may have different functions in the adult organisms but have a similar underlying structure, such as the bones in the human arm and the wing of a bat.

Define Biochemical Similarities

Biochemical similarities refer to the similarities in DNA sequences, proteins, and other biochemical compounds across different species, indicating shared genetic information from a common ancestor.

Analyze the Evidence Provided

Vestigial structures, homologous structures, and biochemical similarities all suggest that different species have inherited these features from a common ancestor. This is supported by evolutionary theory, which posits that species change over time due to descent with modification from a shared ancestor.

Eliminate Incorrect Options

Option b (barriers to migration), option c (random mating), and option d (sexual selection) do not explain the presence of vestigial structures, homologous structures, or biochemical similarities.

Conclusion

Based on the analysis, the presence of vestigial structures, homologous structures, and biochemical similarities supports the idea of descent from a common ancestor.

Key concepts

Vestigial Structures

Vestigial structures are intriguing remnants of evolution. They are anatomical features that no longer serve a purpose in the current form of an organism but were functional in ancestral species. Imagine the human appendix, which is not crucial for our modern digestion but was essential for our herbivorous ancestors. Another example is the pelvic bones found in whales, remnants of their land-dwelling ancestors. By studying these structures, scientists gather evidence of how species have evolved and adapted over time. They reveal a fascinating snapshot of the evolutionary history coded in our bodies.

Homologous Structures

Homologous structures are another key piece of the evolutionary puzzle. These are anatomical features in different species that are similar because of shared ancestry. Interestingly, they might serve different functions in adult organisms. For example, consider the bones in a human arm and the wing of a bat. Structurally, they are quite similar, indicating that humans and bats share a common ancestor. Such structures help scientists understand how diverse life forms can evolve from similar origins, adjusting former structures to meet new needs and environments.

Biochemical Similarities

Biochemical similarities provide deep insights into the genetic connections among species. These similarities refer to the shared DNA sequences, proteins, and other biochemical compounds across different species. Shared genetic information suggests that these species inherited these traits from a common ancestor. For instance, humans share about 98% of their DNA with chimpanzees, illustrating a close evolutionary relationship. By analyzing these molecular similarities, scientists can trace back the lineage of species and understand the genetic blueprint of life's diversity.

Common Ancestor

The concept of a common ancestor is central to evolutionary biology. It suggests that all species are connected through a lineage that traces back to one or a few initial life forms. The presence of vestigial structures, homologous structures, and biochemical similarities all provide evidence supporting this idea. For example, the similarities in embryonic development between certain species point to a shared ancestry. The notion of a common ancestor ties together various observations and evidence, forming a cohesive story of life's evolution on Earth.

Evolutionary Theory

Evolutionary theory is the foundation on which our understanding of biological diversity rests. It posits that species change over time through processes such as natural selection, genetic drift, and gene flow. When considering vestigial structures, homologous structures, and biochemical similarities, evolutionary theory provides a framework to explain these phenomena. For instance, the modification of homologous structures in different environments showcases adaptive evolution. By studying evolutionary theory, scientists can piece together the historical narrative of life's adaptation and change, showing that life on Earth is a dynamic tapestry woven through millions of years.