The Height of a Giraffe *
نویسنده
چکیده
A minor modification of the arguments of Press and Lightman leads to an estimate of the height of the tallest running, breathing organism on a habitable planet as the Bohr radius multiplied by the three-tenths power of the ratio of the electrical to gravitational forces between two protons (rather than the one-quarter power that Press got for the largest animal that would not break in falling over, after making an assumption of unreasonable brittleness). My new estimate gives a height of about 3.6 meters rather than Press's original estimate of about 2.6 cm. It also implies that the number of atoms in the tallest runner is very roughly of the order of the nine-tenths power of the ratio of the electrical to gravitational forces between two protons, about 3 × 10 32 .
منابع مشابه
Giraffe Stature and Neck Elongation: Vigilance as an Evolutionary Mechanism
Giraffe (Giraffa camelopardalis), with their long neck and legs, are unique amongst mammals. How these features evolved is a matter of conjecture. The two leading ideas are the high browse and the sexual-selection hypotheses. While both explain many of the characteristics and the behaviour of giraffe, neither is fully supported by the available evidence. The extended viewing horizon afforded by...
متن کاملSex Differences in Giraffe Feeding Ecology: Energetic and Social Constraints
Sex ratios of giraffe groups differ in different habitats, with open vegetation having female biased groups, and tall, thick vegetation having male-biased groups. On a ranch in south-central Kenya, we quantified habitat differences of male and female giraffe groups and showed that the preference for open habitats by female groups was limited to groups with young. We suggest that this differenc...
متن کاملGiraffe genome sequence reveals clues to its unique morphology and physiology
The origins of giraffe's imposing stature and associated cardiovascular adaptations are unknown. Okapi, which lacks these unique features, is giraffe's closest relative and provides a useful comparison, to identify genetic variation underlying giraffe's long neck and cardiovascular system. The genomes of giraffe and okapi were sequenced, and through comparative analyses genes and pathways were ...
متن کاملIntegrating Shape and Pattern in Mammalian Models
The giraffe and its patches, the leopard and its spots, the tiger and its stripes are spectacular examples of the integration of a pattern and a body shape. We propose in this paper a system which combines and integrates a pattern generation system which can effectively deliver a variety of patterns characteristic of mammalian coats, and a body growth and animation system that can use experimen...
متن کاملFinding Thefl Site Sear
What constitutes a good user interface for search? It depends on the type of answers that users are pursuing. It can be helpful to think of these types of answers as lying along a conceptual continuum , ranging from directed search to informal browsing to text mining and analysis. For example, consider the following questions a user might ask of a large text collection or the Web: 1. How tall i...
متن کاملMulti-locus Analyses Reveal Four Giraffe Species Instead of One
Traditionally, one giraffe species and up to eleven subspecies have been recognized [1]; however, nine subspecies are commonly accepted [2]. Even after a century of research, the distinctness of each giraffe subspecies remains unclear, and the genetic variation across their distribution range has been incompletely explored. Recent genetic studies on mtDNA have shown reciprocal monophyly of the ...
متن کامل