Search results
Results from the WOW.Com Content Network
The indirect route of this nerve is the result of evolution of mammals from fish, which had no neck and had a relatively short nerve that innervated one gill slit and passed near the gill arch. Since then, the gill it innervated has become the larynx and the gill arch has become the dorsal aorta in mammals.
Trace fossils provide us with indirect evidence of life in the past, such as the footprints, tracks, burrows, borings, and feces left behind by animals, rather than the preserved remains of the body of the actual animal itself. Unlike most other fossils, which are produced only after the death of the organism concerned, trace fossils provide us ...
Alternatives to Darwinian evolution have been proposed by scholars investigating biology to explain signs of evolution and the relatedness of different groups of living things. The alternatives in question do not deny that evolutionary changes over time are the origin of the diversity of life, nor that the organisms alive today share a common ...
Beginning of animal evolution. [54] [55] 720–630 Ma Possible global glaciation [56] [57] which increased the atmospheric oxygen and decreased carbon dioxide, and was either caused by land plant evolution [58] or resulted in it. [59] Opinion is divided on whether it increased or decreased biodiversity or the rate of evolution. [60] [61] [62 ...
In general, viruses cannot leave behind physical fossils, [1] therefore indirect evidence is used to reconstruct the past. For example, viruses can cause evolution of their hosts, and the signatures of that evolution can be found and interpreted in the present day. [ 2 ]
Direct benefits are widespread and empirical studies provide evidence for this mechanism of evolution. [19] [20] One example of a sexually selected trait with direct benefits is the bright plumage of the northern cardinal, a common backyard bird in the eastern United States. Male northern cardinals have conspicuous red feathers, while the ...
An example is the production of tetrodotoxin in the rough-skinned newt and the evolution of tetrodotoxin resistance in its predator, the common garter snake. In this predator-prey pair, an evolutionary arms race has produced high levels of toxin in the newt and correspondingly high levels of toxin resistance in the snake.
Evidence for any such direction in evolution is however hard to acquire and can also result from developmental constraints that limit diversification. [75] For example, in the gastropods , the snail-type shell is always built as a tube that grows both in length and in diameter; selection has created a wide variety of shell shapes such as flat ...