Answer:
Charles Darwin thought that the varied animals and plants on the Galapagos Islands had originally come from South America but evolved into different species on the islands.
Step-by-step explanation:
Charles Darwin visited the Galapagos Islands in 1835 and made several observations that led him to develop his theory of evolution by natural selection. One of his key observations was the unique distribution of plants and animals on the different islands of the Galapagos archipelago.
Darwin noticed that many of the species he found on the islands were similar to those found on the nearby South American mainland but had evolved into different species on the islands. For example, the finches he found on the islands had different beak shapes adapted to each island's different types of food.
Based on his observations, Darwin concluded that the animals and plants on the Galapagos Islands had originated from the South American mainland and had gradually evolved into different species on the islands. He proposed that these variations resulted from natural selection, where the individuals with advantageous traits were more likely to survive and reproduce, passing on those traits to their offspring.
In summary, Charles Darwin's theory was that the varied animals and plants on the Galapagos Islands had initially come from South America but had evolved into different species on the islands through natural selection.