Darwin Observed: Fossil Evidence He identified fossils in these ancient coastlines. Some of the organisms were now extinct.

Fossil Evidence Some fossils resembled organisms that were still alive. Like this armadillo fossil. This led Darwin to ask even more questions about the origin of LIFE.

Some of those questions were: Why had so many species disappeared? How were they related to living species?

More of Darwin’s Observations Darwin observed and collected thousands of organisms from all parts of the world. He realized that the plants and animals are well suited for the environments in which they lived. He was impressed by the way animals survived and produced offspring. Many of these organisms were very different even though they lived in similar environments.

Darwin’s Most Important Observations These observations were made on a chain of islands called the Galapagos Islands. 13 main volcanic islands and 6 smaller islands. The first land island formed between 5 and 10 MYA. The islands have a great number of native species. Darwin studied many of these species.

Galapagos Islands These islands are close together but have VERY different climates Some are hot and dry and nearly barren while others have a great amount of rainfall with lush plants.

Species of the Galapagos

Darwin observed that the plants and animals differed from island to island. He wondered if the animals living on different islands had once been members of the same species. What do you think?

Darwin chose to focus his work on various finch species that he observed

Darwin’s Observations Similarities: The birds are all about the same size (10-20cm) The birds are all brownish or black Differences: Size and shape of the beaks Different song melodies

What he realized: The individual finch species were uniquely related to the habitat of the island they lived on. OVER TIME their beaks adapted to the food sources available on that island. This gave Darwin the idea that these different finch species were formed from a common ancestor. This common ancestor was most likely from the mainland of South America.

Individual Finch Species Common Ancestor