Final answer:
Evidence for the continents once being joined includes fossil records of similar species, matching coastlines and geological formations, and similar climate patterns, all supporting the former existence of the supercontinent Pangaea.
Step-by-step explanation:
Summary of Evidence for Continents Once Being Joined:
The theory that continents were once joined is supported by several lines of evidence. Fossil records show that similar species are found on continents that are now separated by vast oceans, an indication that these continents were once connected. Matching coastlines and geological formations suggest that continents like South America and Africa once fit together like pieces of a puzzle. Additionally similar climate patterns evident from geological studies imply that continents once experienced common climatic conditions when they were part of a supercontinent.
All of these factors contribute to the robust evidence for the existence of the supercontinent Pangaea, which is understood to have existed about 200 million years ago. Alfred Wegener the German scientist who first proposed the idea of continental drift in 1915 based his hypothesis on these various observations. Despite initial skepticism, further scientific research has since corroborated Wegener's theory, particularly with advancements in plate tectonics during the 1960s.