Showing papers in "The Quarterly Review of Biology in 1971"

The Evolution of Reciprocal Altruism

Abstract: A model is presented to account for the natural selection of what is termed reciprocally altruistic behavior. The model shows how selection can operate against the cheater (non-reciprocator) in the system. Three instances of altruistic behavior are discussed, the evolution of which the model can explain: (1) behavior involved in cleaning symbioses; (2) warning cries in birds; and (3) human reciprocal altruism. Regarding human reciprocal altruism, it is shown that the details of the psychological system that regulates this altruism can be explained by the model. Specifically, friendship, dislike, moralistic aggression, gratitude, sympathy, trust, suspicion, trustworthiness, aspects of guilt, and some forms of dishonesty and hypocrisy can be explained as important adaptations to regulate the altruistic system. Each individual human is seen as possessing altruistic and cheating tendencies, the expression of which is sensitive to developmental variables that were selected to set the tendencies at a balance ap...

Repetitive and non-repetitive DNA sequences and a speculation on the origins of evolutionary novelty.

Abstract: Recent experimental information on DNA sequence repetition is reviewed, and the significance of both repetitive and non-repetitive sequence considered. Included are a summary of data on the distribution of genome sizes in animals, new experiments on interspecific DNA homology, the distribution of sequence frequencies, and the interspersion of repetitive sequences within the genome. Aspects of the process of evolution are considered at the level of change in the DNA. the process by which novel structure and function could have arisen during evolution are considered speculatively in terms of the authors' gene regulation theory (Britten and Davidson, 1969).

Semidwarf rice and wheat in global food needs.

Abstract: Rice and wheat together provide about three-fourths of the total food-grain supply consumed by man. Because of rapidly increasing population, per capita grain output in the underdeveloped regions of the world delined during the 1940's and 1950's. Fertilizer is a key factor in increasing agricultural production. Recently, several underdeveloped nations made major efforts to increase the use of fertilizer. But traditional varieties of wheat and rice did not respond to fertilizer efficiently. Attempts to breed fertilizer-responsive varieties were generally unsuccessful until plant breders discovered the Chinese rice Dee-geo-woo-gen and the Japanese wheat Norin 10 and used them in breeding programs. This resulted in the development of the semidwarf rice, Taichung Native 1, in 1956 in Taiwan and the semidwarf wheat, Gaines, in 1961 in the U. S. A. The most extensive use of the semidwarfing genes was made by the Mexican wheat program and at the International Rice Research Institute. Several Mexican semidwarf wh...

A Theory of the Evolution of Therian Dental Formulas and Replacement Patterns

Abstract: An explanation of certain dental characteristics of metatherian and eutherian mammals is synthesized from ontogenetical, paleontological, and morphological observations. The two therian dental sets represent the two successive Zahnreihen of an as yet unknown therapsid. The molars are serially homologous with the primary Zahnreihe or milk dentition. Generally, molar number decreased from eight or nine in the ancestral therapsid and primitive pantothere to four in the mid-Cretaceous eupantotherian stock. Occasional reversals of this process took place, the addition (and subtraction) always occurring at the posterior end of the molar row. However, the antemolar number has seldom, and perhaps never, increased. Through the Jurassic and well into the Cretaceous, the maximum incisor number probably remained five above and four below. The maximum premolar number remained four in both jaws, although selective pressures favored a gradual retardation in development time of both milk and replacement first premolars. ...

Phylogeny and ecology of mycotrophic achlorophyllous angiosperms

Abstract: Achlorophyllous genera of angiosperms, such as Galeola (Orchidaceae), Leiphaimos (Gentianaceae), and Monotropa (Pyrolaceae), have evolved highly specialized, mycotrophic root systems, along with chlorosis and complex floral morphologies. Productivity rates of most such plants cannot be satisfactorily explained by the saprophytic niche which is often assumed as theirs but is inadequately nutritious. Rather, they parasitize their mycorrhizal fungi. When a mycorrhizal fungus is shared by roots of an achlorophyllous angiosperm an those of a photosynthesizing plant, the former can indirectly parasitize the latter via the connecting mycelium (epiparasitism). The functional mycelial connection between the mycorrhizae of epiparasites and those of associated host trees has been demonstrated by radiotracer techniques. Some epiparasites are very locally distributed. The ecological requirements of their mycorrhizal fungi, such a suitable host trees, may explain much of this localization. A taxonomic survey of the Orc...

Continental Drift and the Evolution of the Biota on Southern Continents

Abstract: The post-1960 geological evidence, and postulations, concerning continental drift are summarized. These, and the newer fossil data, support the existence of a southern Gondwana supercontinent until about the mid-Triassic. There is less agreement about the timing and pattern of the phases of the subsequent break-up; while geologists are in general agreement that the South Atlantic, for example, opened up in the Jurassic or Early Cretaceous, the data derived from the various techniques employed, and the "models" based on them, are in wide disagreement when it comes to the history of India. Biological data relating to continental drift stem from two sources, the fossil record and contemporary biotas. Paleontology tells little about the distribution of the southern land masses during the Jurassic and Cretaceous, although the wide distribution of certain dinosaurs, long a subject for debate (e.g., Matthew, 1915; von Huene and Matley, 1933), argues strongly against the very isolated positions for Australia and ...

Coevolution of the Rust Fungi and Their Hosts

Abstract: The rust fungi are fully parasitic and arose from parasitic ancestors. Heteroecism was evidently universal during their major evolutionary outburst. Thus, the ecology of hosts and parasites was complexly interrelated and profundly influenced the evolution of the rusts. Divergence with their hosts probably has been the chief means of speciation in the rusts. Part of the process, especially in the more advanced groups, has been the initiation of autoecious species on the aecial hosts of parental heteroecious ones. This change may have triggered an evolutionary outburst through partial release from the ecological limits of the heteroecious ancestor. Jumps to hosts of varying taxonomic separation from the ancestral host must have given rise to many species and to some lineages; but few are easily documented. A single example suggests that a hybrid rust may be adapted to a hybrid between its parental hosts; and, if the hybrid host speciates, the rust may do so also.

The Adaptation and Evolution of Early Fishes

Abstract: The origin and evolution of some fundamental adaptations of early vertebrates are examined in terms of theoretical considerations and the limited available data on living and fossil chordates. Special emphasis is given to the question of the interrelatedness of apparently widely different functions in general biological activity and in evolutionary processes. Problems in the evolution of calcified systems and the notochord are discussed in the light of recent advances. A new explanation of the mechanical significance of the heterocercal tail is proposed, along with a revision of its evolution, based on new interpretations of the directionality of the thrust produced by the separate parts of the tail. The respiratory patterns of early fishes are discussed with special reference to the question of the origin of auxiliary earial respiration and it is concluded that lungs were probably an extremely early adaptation of fresh water fishes. Jaw mechanisms are examined and a revised scheme proposed for the evolut...

Behavior in Polychaetes

Abstract: It is suggested that, because of their relatively simple repertoires of behavior, polychaetes may be particularly useful in behavioral research. An interesting range of responses has already been described in these animals, including those involved in habitat selection, feeding, tube construction, escape from predators, fighting, pairing, swarming, commensalism, and learning. In at least lugworms and some other polychaetes, much of the behavior has been shown to consist of spontaneous cycles of activity triggered by internal pacemakers. So far, little attention has been paid to the role of the central nervous system, but extirpations of parts of it in nereids have produced interesting results. The feature of particular interest in the brains of several polychaete families is the presence of corpora pedunculata. The function of these lobes is unknown, but they are well developed in nereids and polynoids, which lead unusually active lives.

Tetrapods and Continents

Abstract: The affinities of modern land-living animals are intimately related to the positions and connections of continents, a fact nicely demonstrated by mammalian faunas throughout the world. The zoogeography of modern mammals has roots in the various distributions of mammals during Cenozoic time. In the Paleozoic and Mesozoic eras, the relationship between continental positions and tetrapod faunas is reflected by the distributions of extinct amphibians and reptiles. The early Triassic Lystrosaurus fauna, an example of this, originally described from South Africa, is now known in Antarctica, in peninsular India, and in western China. The distributions of this ancient tetrapod fauna, as well as of other later Mesozoic faunas, indicate that the regions in which they now occur were then intimately associated, allowing for the ready intermigrations of land-living vertebrates. This lends strong support to the theory of Gondwanaland, which supposes the southern hemisphere continents plus peninsular India to have been ...

Principles of Comparative Anatomy of Invertebrates. Volume 1: Promorphology. Volume 2: Organology.W. N. Beklemishev , J. M. MacLennan , Z. Kabata

Abstract: New updated! The latest book from a very famous author finally comes out. Book of principles of comparative anatomy of invertebrates volume 1 promorphology volume 2 organology, as an amazing reference becomes what you need to get. What's for is this book? Are you still thinking for what the book is? Well, this is what you probably will get. You should have made proper choices for your better life. Book, as a source that may involve the facts, opinion, literature, religion, and many others are the great friends to join with.