Origin and history of dogs Ancestry Paleontologists and archaeologists have determined that about 60 million years ago a small mammal, rather like a weasellived in the environs of what are now parts of Asia. It is called Miacisthe genus that became the ancestor of the animals known today as canids: Miacis did not leave direct descendants, but doglike canids evolved from it.
See Article History Zoology, branch of biology that studies the members of the animal kingdom and animal life in general. It includes both the inquiry into individual animals and their constituent parts, even to the molecular level, and the inquiry into animal populations, entire faunas, and the relationships of animals to each other, to plants, and to the nonliving environment.
Though this wide range of studies results in some isolation of specialties within zoology, the conceptual integration in the contemporary study of living things that has occurred in recent years emphasizes the structural and functional unity of life rather than its diversity.
Domestication of animals forced man to take a systematic and measured view of animal life, especially after urbanization necessitated a constant and large supply of animal products. Study of animal life by the ancient Greeks became more rational, if not yet scientific, in the modern sense, after the cause of disease—until then thought to be demons—was postulated by Hippocrates to result from a lack of harmonious functioning of body parts.
In Roman times Pliny brought together in 37 volumes a treatiseHistoria naturalisthat was an encyclopaedic compilation of both myth and fact regarding celestial bodies, geography, animals and plants, metals, and stone.
Zoology continued in the Aristotelian tradition for many centuries in the Mediterranean region and by the Middle Ages, in Europe, it had accumulated considerable folklore, superstition, and moral symbolisms, which were added to otherwise objective information about animals.
Gradually, much of this misinformation was sifted out: The use of the printing press in the 15th century made possible an accurate transmission of information. Moreover, mechanistic views of life processes i.
In the 18th century, zoology passed through reforms provided by both the system of nomenclature of Carolus Linnaeus and the comprehensive works on natural history by Georges-Louis Leclerc de Buffon; to these were added the contributions to comparative anatomy by Georges Cuvier in the early 19th century.
Physiological functions, such as digestion, excretion, and respiration, were easily observed in many animals, though they were not as critically analyzed as was blood circulation.
Following the introduction of the word cell in the 17th century and microscopic observation of these structures throughout the 18th century, the cell was incisively defined as the common structural unit of living things in by two Germans: Matthias Schleiden and Theodor Schwann.
In the meanwhile, as the science of chemistry developed, it was inevitably extended to an analysis of animate systems.
And in the midth century the French physician and physiologist Claude Bernard drew upon both the cell theory and knowledge of chemistry to develop the concept of the stability of the internal bodily environmentnow called homeostasis.
The cell concept influenced many biological disciplinesincluding that of embryologyin which cells are important in determining the way in which a fertilized egg develops into a new organism.
The unfolding of these events—called epigenesis by Harvey—was described by various workers, notably the German-trained comparative embryologist Karl von Baerwho was the first to observe a mammalian egg within an ovary. Another German-trained embryologist, Christian Heinrich Panderintroduced in the concept of germ, or primordialtissue layers into embryology.
In the latter part of the 19th century, improved microscopy and better staining techniques using aniline dyes, such as hematoxylin, provided further impetus to the study of internal cellular structure. The theory of evolution —that organisms are continuously evolving into highly adapted forms —required the rejection of the static view that all species are especially created and upset the Linnaean concept of species types.
Darwin recognized that the principles of heredity must be known to understand how evolution works; but, even though the concept of hereditary factors had by then been formulated by Mendel, Darwin never heard of his work, which was essentially lost until its rediscovery in Genetics has developed in the 20th century and now is essential to many diverse biological disciplines.
The discovery of the gene as a controlling hereditary factor for all forms of life has been a major accomplishment of modern biology.
There has also emerged clearer understanding of the interaction of organisms with their environment. Closely related to this study of ecology are inquiries into animal behaviouror ethology.
Such studies are often cross disciplinary in that ecology, physiology, genetics, development, and evolution are combined as man attempts to understand why an organism behaves as it does. The emergence of animal biology has had two particular effects on classical zoology.
First, and somewhat paradoxically, there has been a reduced emphasis on zoology as a distinct subject of scientific study; for example, workers think of themselves as geneticists, ecologists, or physiologists who study animal rather than plant material.
They often choose a problem congenial to their intellectual tastes, regarding the organism used as important only to the extent that it provides favourable experimental material.Genome-wide complex trait analysis (GCTA) Genome-based restricted maximum likelihood (GREML) is a statistical method for variance component estimation in genetics which quantifies the total narrow-sense (additive) contribution to a trait's heritability of a particular subset of genetic variants (typically limited to SNPs with MAF >1%, hence .
I. Albion’s Seed by David Fischer is a history professor’s nine-hundred-page treatise on patterns of early immigration to the Eastern United States. It’s not light reading and not the sort of thing I would normally pick up. I read it anyway on the advice of people who kept telling me it explains everything about America.
Zoology: Zoology, branch of biology that studies the members of the animal kingdom and animal life in general. It includes both the inquiry into individual animals and their constituent parts, even to the molecular level, and the inquiry into animal populations, entire faunas, and the relationships of.
The word “race,” denoting lineage, comes from a French translation of haras (silent “h”) into the Italian razza — which in Italian of that time applied to animals, not ashio-midori.com points to current English and Italian usage being derived and adapted, respectively, from the French.
THE FALSE ALLURE OF GROUP SELECTION. Human beings live in groups, are affected by the fortunes of their groups, and sometimes make sacrifices that benefit their groups. The Moments That Make Us Who We Are. Life provides turning points of many kinds, but the most powerful of all may be character-revealing moments.