First section.
Evidence for whale evolution.
I have written about this multiple times, and since it has come up I thought I would gather it up into a post or two.
I may add more later.
Biological
-Limbs
Here are three pictures of Mammal limbs
From: http://www.earthlife.net/mammals/skeleton.html
From: http://www.ftexploring.com/
Whales have retained the hand bones of their earlier land dwelling ancestors. This is a commonality between practically all mammals no matter where they are. In whales the hand bones are fussed together to create a single flipper. Other aquatic life that don't have the same evolutionary lineage as the whale also don't share their flipper design, for example, a sharks flippers are made from a single piece of cartilage and not a hand like bone structure.
Legs
Figure 2.2.1. Bones from the atavistic hind-limbs of a humpback whale. A. From top to bottom, the cartiliginous femur, tibia, tarsus, and metatarsal, arranged as found in situ in the whale. B. Enlarged detail of the femur and tibia shown in A. (scale is not the same as A). C. Detail of the tarsus and metatarsal shown in A. (Image reproduced from Andrews 1921, Figures 2, 3, and 4.)
http://www.talkorigins.org/faqs/comdesc/section2.html
Whales have also retained leg bones, although inside their body. Some have even been found to have feet connected to these bones with complete digits.
-Hair
Whales develop body hair in the womb but lose all expect for sensory bristles around the blowhole.
-DNA
"Molecular studies by Goodman and others (1985) show that whales are more closely related to the ungulates than they are to all other mammals."
"Irwin and Arnason (1994), Milinkovitch (1992), Graur and Higgins (1994), Gatesy and others (1996), and Shimamura and others (1997) also identified the whales as closely related to the artiodactyls"
http://www.talkorigins.org/features/whales/
This means that the DNA in whales is more closely related to ungulates and artiodactyls (a type of ungulate) than to other aquatic mammals. Providing evidence for their lineage. This also helped us understand the lineage better. It was originally thought whales evolved directly from Mesonychids (an extinct form of ungulate) because the fossils showed similar characteristics. The new DNA evidence shows that they most likely split from artiodactyls not long after artiodactyls split from Mesonychids, giving early whales the characteristics of mesonychids but DNA more closely related to artiodactyls.
Fossil
Summarized from http://www.talkorigins.org/faqs/faq-transitional/part2b.html
Eoconodon or similar triisodontine arctocyonids (early Paleocene) -- Similar to the early exyclaenid condylarths, had strong canine teeth, blunt cheek teeth and flattened claws.
Microclaenodon (mid-Paleocene) -- A transitional genus intermediate between Eoconodon and the Mesonychids. Its molar teeth are reorganized to look like premolars. It was adapted more toward carnivory.
Dissacus (mid-Paleocene) -- Molars closer to premolars and other tooth changes.
Hapalodectes or a very similar mesonychid (early Eocene, around 55 Ma) -- Very narrow shearing molars, a distinctively shape zygomatic arch and vascularized areas between the molars. probably a close relative to the whale ancestor.
Pakicetus (early-mid Eocene, 52 Ma) -- The oldest fossil whale known. Terrestrial ears, not that good for underwater sound location or deep diving. Molars have very mesonychid like cusps but other teeth are like those of later whales. Nostrils are still at the front of the head.
Ambulocetus natans (early-mid Eocene, 50 Ma) -- Still retains four legs, although they were stubby. Had large back feet that stuck out like tail flukes but lacked real tail flukes and had a simple long tail. Long snout with no blowhole.
Rodhocetus (mid-Eocene, 46 Ma) -- Smaller hind legs with a powerful tail. Nostrils had moved back from the tip of the snout.
Basilosaurus isis, Protocetes, Indocetus ramani and similar small-legged whales of the mid-late Eocene (45-42 Ma) -- Still retained hind legs but most likely couldn't walk on them anymore. B isis might have bee a cousin to the modern whale.
Prozeuglodon (late Eocene, 40 Ma) -- Hind legs almost gone but still present. 6" hind legs on a 15 foot body.
Eocetus, & similar "archeocete whales" of the late Eocene -- More advanced whales, that had lost their hind legs, but retained more primitive skull and teeth with unfused nostrils. Much larger streamline bodies with a tail fluke.
In the Oligocene, whales split into two lineages:
1. Toothed whales:
Agorophius (late Oligocene) -- partly telescoped skull with cheek teeth still rooted.
Prosqualodon (late Oligocene) -- Fully telescoped skull with nostrils on top
Kentriodon (mid-Miocene) -- Skull telescoped but still symmetrical.
2. Baleen (toothless) whales:
Aetiocetus (late Oligocene) -- Most primitive mysticete whale. Most likely the stem group for all baleen whales. mysticete style loose jaw hinge and air sinus, but retained its teeth
Mesocetus (mid-Miocene) --- lost its teeth.
Modern baleen whales first appeared in the late Miocene.
-Strata
I should point out that not only does the morphological appearance show an evolution but if the fossils were organized by strata and age we would get the same list.
Conclusion
Whale evolution is a good transitional set because we not only have transitional fossils but multiple pieces of evidence all pointing in the same direction. This is also a quick way around the "kind" game, since I have yet to see a definition of "kinds" that considers land mammals and aquatic mammals to be within a kind.
Evidence for whale evolution.
I have written about this multiple times, and since it has come up I thought I would gather it up into a post or two.
I may add more later.
Biological
-Limbs
Here are three pictures of Mammal limbs


From: http://www.earthlife.net/mammals/skeleton.html

From: http://www.ftexploring.com/
Whales have retained the hand bones of their earlier land dwelling ancestors. This is a commonality between practically all mammals no matter where they are. In whales the hand bones are fussed together to create a single flipper. Other aquatic life that don't have the same evolutionary lineage as the whale also don't share their flipper design, for example, a sharks flippers are made from a single piece of cartilage and not a hand like bone structure.
Legs

Figure 2.2.1. Bones from the atavistic hind-limbs of a humpback whale. A. From top to bottom, the cartiliginous femur, tibia, tarsus, and metatarsal, arranged as found in situ in the whale. B. Enlarged detail of the femur and tibia shown in A. (scale is not the same as A). C. Detail of the tarsus and metatarsal shown in A. (Image reproduced from Andrews 1921, Figures 2, 3, and 4.)
http://www.talkorigins.org/faqs/comdesc/section2.html
Whales have also retained leg bones, although inside their body. Some have even been found to have feet connected to these bones with complete digits.
-Hair
Whales develop body hair in the womb but lose all expect for sensory bristles around the blowhole.
-DNA
"Molecular studies by Goodman and others (1985) show that whales are more closely related to the ungulates than they are to all other mammals."
"Irwin and Arnason (1994), Milinkovitch (1992), Graur and Higgins (1994), Gatesy and others (1996), and Shimamura and others (1997) also identified the whales as closely related to the artiodactyls"
http://www.talkorigins.org/features/whales/
This means that the DNA in whales is more closely related to ungulates and artiodactyls (a type of ungulate) than to other aquatic mammals. Providing evidence for their lineage. This also helped us understand the lineage better. It was originally thought whales evolved directly from Mesonychids (an extinct form of ungulate) because the fossils showed similar characteristics. The new DNA evidence shows that they most likely split from artiodactyls not long after artiodactyls split from Mesonychids, giving early whales the characteristics of mesonychids but DNA more closely related to artiodactyls.
Fossil
Summarized from http://www.talkorigins.org/faqs/faq-transitional/part2b.html
Eoconodon or similar triisodontine arctocyonids (early Paleocene) -- Similar to the early exyclaenid condylarths, had strong canine teeth, blunt cheek teeth and flattened claws.
Microclaenodon (mid-Paleocene) -- A transitional genus intermediate between Eoconodon and the Mesonychids. Its molar teeth are reorganized to look like premolars. It was adapted more toward carnivory.
Dissacus (mid-Paleocene) -- Molars closer to premolars and other tooth changes.
Hapalodectes or a very similar mesonychid (early Eocene, around 55 Ma) -- Very narrow shearing molars, a distinctively shape zygomatic arch and vascularized areas between the molars. probably a close relative to the whale ancestor.
Pakicetus (early-mid Eocene, 52 Ma) -- The oldest fossil whale known. Terrestrial ears, not that good for underwater sound location or deep diving. Molars have very mesonychid like cusps but other teeth are like those of later whales. Nostrils are still at the front of the head.
Ambulocetus natans (early-mid Eocene, 50 Ma) -- Still retains four legs, although they were stubby. Had large back feet that stuck out like tail flukes but lacked real tail flukes and had a simple long tail. Long snout with no blowhole.
Rodhocetus (mid-Eocene, 46 Ma) -- Smaller hind legs with a powerful tail. Nostrils had moved back from the tip of the snout.
Basilosaurus isis, Protocetes, Indocetus ramani and similar small-legged whales of the mid-late Eocene (45-42 Ma) -- Still retained hind legs but most likely couldn't walk on them anymore. B isis might have bee a cousin to the modern whale.
Prozeuglodon (late Eocene, 40 Ma) -- Hind legs almost gone but still present. 6" hind legs on a 15 foot body.
Eocetus, & similar "archeocete whales" of the late Eocene -- More advanced whales, that had lost their hind legs, but retained more primitive skull and teeth with unfused nostrils. Much larger streamline bodies with a tail fluke.
In the Oligocene, whales split into two lineages:
1. Toothed whales:
Agorophius (late Oligocene) -- partly telescoped skull with cheek teeth still rooted.
Prosqualodon (late Oligocene) -- Fully telescoped skull with nostrils on top
Kentriodon (mid-Miocene) -- Skull telescoped but still symmetrical.
2. Baleen (toothless) whales:
Aetiocetus (late Oligocene) -- Most primitive mysticete whale. Most likely the stem group for all baleen whales. mysticete style loose jaw hinge and air sinus, but retained its teeth
Mesocetus (mid-Miocene) --- lost its teeth.
Modern baleen whales first appeared in the late Miocene.
-Strata
I should point out that not only does the morphological appearance show an evolution but if the fossils were organized by strata and age we would get the same list.
Conclusion
Whale evolution is a good transitional set because we not only have transitional fossils but multiple pieces of evidence all pointing in the same direction. This is also a quick way around the "kind" game, since I have yet to see a definition of "kinds" that considers land mammals and aquatic mammals to be within a kind.