Search results
Results From The WOW.Com Content Network
The evolution of fishes took place over a timeline which spans the Cambrian to the Cenozoic, including during that time in particular the Devonian, which has been dubbed the "age of fishes" for the many changes during that period. The Late Devonian extinctions played a crucial role in shaping the evolution of fish, or vertebrates in general. [1]
The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish lineages belong to the Agnatha, or jawless fish. Early examples include Haikouichthys.
Young sporophytes of the common moss Tortula muralis. In mosses, the gametophyte is the dominant generation, while the sporophytes consist of sporangium-bearing stalks growing from the tips of the gametophytes Sporophytes of moss during spring In flowering plants, the sporophyte comprises the whole multicellular body except the pollen and ...
Altogether the ocean occupies 71 percent of the world surface, [4] averaging nearly 3.7 kilometres (2.3 mi) in depth. [27] By volume, the ocean provides about 90 percent of the living space on the planet. [4] The science fiction writer Arthur C. Clarke has pointed out it would be more appropriate to refer to planet Earth as planet Ocean. [28] [29]
A newfound fossil of a jawless fish is the oldest known vertebrate cranium preserved in 3D. The 455 million-year-old find could illuminate how vertebrate heads evolved.
There was a loss of opercular and extrascapular elements, enhancing head mobility in T. roseae compared to other tetrapodomorph fish. [1] The formation of the neck allowed for locomotion in shallow waters. This environment allows for less motility compared to the three-dimensional space that fish are able to orient themselves in.
The existence of a separate water body in these periods was deduced from the fossil fauna, including mollusks, fish and ostracods. In periods in which the Paratethys or parts of it were separated from each other or from other oceans, a separate fauna developed which is found in sedimentary deposits.
A rarely seen deep sea fish resembling a serpent was found floating dead on the ocean surface off the San Diego coast and was brought ashore for study, marine experts said. The silvery, 12-foot ...