Final answer:
In the 19th century, objections to Darwin's theory of evolution included the absence of a mechanism for inheritance, misconceptions about the Earth's age, and the appearance of design in organisms. These were resolved by the discoveries in genetics, radioactive dating, and population genetics. It highlights how scientific theories can develop and become more robust as new evidence is discovered.
Step-by-step explanation:
When Charles Darwin first presented his theory of evolution by natural selection, it faced stiff opposition from various quarters. Three major objections that were prominent in the 19th century include the lack of a mechanism to explain inheritance, the age of the Earth, and the appearance of design in organisms.
Mechanism of Inheritance
One major objection was the absence of a mechanism that could explain how traits were inherited from one generation to the next. It was only with the rediscovery of Gregor Mendel's work on genetics in the early 20th century that scientists could explain how characteristics were passed down, thereby strengthening the theory of evolution.
Age of the Earth
Another objection came from the misunderstanding about the Earth's age. Many believed the Earth to be only around 6,000 years old, which would not have allowed enough time for evolution to occur. The 20th-century discovery of radioactive dating techniques by physicists showed that the Earth is actually billions of years old, providing ample time for evolutionary processes.
Appearance of Design
The complexity and seeming perfect design of organisms led some to argue that they must have been designed by a deity. The development of the field of population genetics and the understanding of genetic drift, gene flow, and mutation provided a well-founded explanation for how complex structures could evolve naturally.
This history tells us that a theory, like Darwin's, can be extremely useful even if it doesn't answer all questions initially. It serves as a framework for further investigation and, as new evidence emerges, it can be refined and strengthened. The successful refinement and acceptance of evolutionary theory thus illustrate science's progressive nature, where theories evolve and adapt in light of new evidence.