Evolution: generating novelty by symbiosis
Article Abstract:
Symbiosis exists when two dissimilar organisms live together. The evolution of eukaryotes, higher organisms, from prokaryotes, lower organisms such as bacteria, involved symbiosis. Single-celled organisms have acquired higher functions, such as motility or antibiotic resistance by the joining of genetic material from two ancestors into one descendent. There are a number of examples of the symbiotic relationships of organisms such as: termites which can digest cellulose from plants because of organisms they have in their gut, and certain plants which can live in acid peat soil because they have an organism which can get nutrients from the soil. Another example is the Leiognathid fish or flashlight fish which uses light organs to increase its vision and to signal other fish. The light is generated by bacteria. This examination questions whether other major novelties have developed in evolution by symbiosis. For instance, bacteria allows the flashlight fish to luminesce, but other features such as reflectors and movable shutters have evolved in the fish. The issue of novelty by gradualism verses sudden innovation (i.e., a miracle) is discussed. Traits develop by mutation and natural selection, where organisms with advantageous traits survive and these traits are passed to future generations. Although a single mutation can produce large changes such as a change in structure, other features must adapt to this change. The kinds of novelties to be introduced by symbiosis could include various traits involved in the metabolic processes necessary for life, such as vitamin synthesis, which occur readily in bacteria but not in higher organisms. The origin of symbiosis, may stem from either parasitism where one organism, needs another organism to live, but eventually kills the other organism, or from mutualism, where both organisms need each other to survive.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1989
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The major evolutionary transitions
Article Abstract:
A series of prominent evolutionary transitions account for the increased complexity of evolutionary lineages with time. These complexities are characterized by changes in the manner in which data is stored and transmitted. Evolutionary transitions and associated biological complexity are influenced by protein-coding genes and cell morphology.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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Evolution of genetic redundancy
Article Abstract:
Scientists have used a genetic model to determine the redundancy process of genes in evolution and conclude that genetic redundancy occurs often during evolution. Selection pressures on redundant genes are assessed and established using four models as described.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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