A) Fossils can be dated using a method called radiometric dating. B) Fossils can be dated relative to other fossils found in layers of rock. C) Fossils can be dated using a microscope to examine tissue. D) Fossils can be dated by dating the rock in which they are discovered.
Oct 12, 2018 · Chimpanzees exhibit 99% genetic similarity to humans. Cows share approximately 80% of their DNA sequence with humans. Scientists can predict the relative age of a common ancestor using DNA sequences.
Tiktaalik (/ t ɪ k ˈ t ɑː l ɪ k /; Inuktitut ᑎᒃᑖᓕᒃ) is a monospecific genus of extinct sarcopterygian (lobe-finned fish) from the Late Devonian Period, about 375 Mya (million years ago), having many features akin to those of tetrapods (four-legged animals).. Unearthed in Arctic Canada, Tiktaalik is technically a fish, complete with scales and gills – but it has a triangular ...
Tiktaalik generally had the characteristics of a lobe-finned fish, but with front fins featuring arm-like skeletal structures more akin to those of a crocodile, including a shoulder, elbow, and wrist. The fossil discovered in 2004 did not include the rear fins and tail.
Tiktaalik roseae is the only species classified under the genus. Tiktaalik lived approximately 375 million years ago. It is representative of the transition between non-tetrapod vertebrates (fish) such as Panderichthys, known from fossils 380 million years old, and early tetrapods such as Acanthostega and Ichthyostega, ...
The alligator gar is an extant fish that bears some resemblance to Tiktaalik. Also notable are the spiracles on the top of the head, which suggest the creature had primitive lungs as well as gills. This attribute would have been useful in shallow water, where higher water temperature would lower oxygen content.
The phylogenetic analysis by Daeschler et al. placed Tiktaalik as a sister taxon to Elpistostege and directly above Panderichthys preceded by Eusthenopteron. Tiktaalik was thus inserted below Acanthostega and Ichthyostega as a transitional form and a true "missing link".