page_title: List of transitional fossils
hierarchical_section_title: List of transitional fossils
caption_attribution_description: English: Archaeopteryx lithographica, specimen displayed at the Museum für Naturkunde in Berlin. (This image shows the original fossil - not a cast.) Deutsch: Archaeopteryx lithographica, Exemplar im Museum für Naturkunde in Berlin. (Dieses Bild zeigt das Original-Fossil, keinen Abguss.)
context_page_description: This is a tentative partial list of transitional fossils. The fossils are listed in series, showing the transition from one group to another, representing significant steps in the evolution of major features in various lineages. These changes often represent major changes in morphology and anatomy, related to mode of life, like the acquisition of feathered wings for an aerial lifestyle in birds, or limbs in the fish/tetrapod transition onto land.
  Darwin noted that transitional forms could be considered common ancestors, direct ancestors or collateral ancestors of living or extinct groups, but believed that finding actual common or direct ancestors linking different groups was unlikely. Collateral ancestors are relatives like cousins in genealogies in which they are not in your direct line of descent but do share a common ancestor. This kind of thinking can be extended to groups of life. For instance, the well-known Archaeopteryx is a transitional form between non-avian dinosaurs and birds, but it is not the most recent common ancestor of all birds nor is it a direct ancestor of any species of bird alive today.
context_section_description: This is a tentative partial list of transitional fossils (fossil remains of groups that exhibits both "primitive" and derived traits). The fossils are listed in series, showing the transition from one group to another, representing significant steps in the evolution of major features in various lineages. These changes often represent major changes in morphology and anatomy, related to mode of life, like the acquisition of feathered wings for an aerial lifestyle in birds, or limbs in the fish/tetrapod transition onto land.
  Darwin noted that transitional forms could be considered common ancestors, direct ancestors or collateral ancestors of living or extinct groups, but believed that finding actual common or direct ancestors linking different groups was unlikely. Collateral ancestors are relatives like cousins in genealogies in which they are not in your direct line of descent but do share a common ancestor (in this case it is a grandparent). This kind of thinking can be extended to groups of life. For instance, the well-known Archaeopteryx is a transitional form between non-avian dinosaurs and birds, but it is not the most recent common ancestor of all birds nor is it a direct ancestor of any species of bird alive today. Rather, it is considered an extinct close evolutionary "cousin" to the direct ancestors. This may not always be the case, though, as some fossil species are proposed to be directly ancestral to others, like how Australopithecus anamensis is most likely to be ancestral to Australopithecus afarensis.
caption: Possibly the best known of all transitional fossils, the Berlin specimen of Archaeopteryx lithographica
exif: {"Image Orientation": "Horizontal (normal)", "Image XResolution": "180", "Image YResolution": "180", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS2 Windows", "Image DateTime": "2013:02:28 19:40:20", "Image ExifOffset": "164", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "302", "Thumbnail JPEGInterchangeFormatLength": "5507", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "1888", "EXIF ExifImageLength": "2552"}