Final answer:
Fossils are the preserved remains of ancient animals that serve as evidence of evolution. Paleontologists study these remains, revealing how species have changed over time and showing connections between different species.
Step-by-step explanation:
The preserved remains of ancient animals are known as fossils. These fossils include bones, teeth, and impressions, providing evidence that organisms from the past are not the same as those found today. Paleontologists are scientists who study fossils to understand how species have evolved over time. Fossils help in determining the features and lifestyles of extinct species, and through comparison of different species' features from various periods, a better understanding of evolution emerges.
For example, the fossil record of horses shows a clear progression of evolutionary changes in size, hoof structure, and tooth morphology reflecting adaptations to different environments over millions of years. Additionally, the similarity between the flippers of whales and the limbs of mammals and birds indicates these species share a common ancestor, evidencing a shared evolutionary path.
Fossils, therefore, not only document the existence of species that have since gone extinct but also the gradual changes that occurred over time, aiding paleontologists in piecing together the evolutionary history of life on Earth.