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pyramid of numbers

The characteristic decrease in the relative numbers of animals at each successively higher level in the food chain of a natural ecosystem (see illustration). Pyramid ...

pyramid of numbers

pyramid of numbers n.   Quick reference

A Dictionary of Psychology (4 ed.)

Reference type:
Subject Reference
Current Version:
2015
Subject:
Science and technology, Psychology, Medicine and health, Psychiatry
Length:
35 words
Illustration(s):
1

... of numbers n . The characteristic decrease in the relative numbers of animals at each successively higher level in the food chain of a natural ecosystem (see illustration). Pyramid of numbers. A woodland food...

pyramid of numbers

pyramid of numbers   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

... of numbers A diagrammatic expression of the numbers of individual organisms present at each trophic level of an ecosystem . It is the least useful of the three types of ecological pyramid since it makes no allowance for the different sizes and metabolic rates of organisms. Typically it slopes more steeply than the other pyramids and may be inverted, e.g. when based on studies of temperate woodlands in summer. Compare pyramid of biomass ; pyramid of energy ; see also ecological pyramid...

pyramid of numbers

pyramid of numbers   Quick reference

A Dictionary of Plant Sciences (4 ed.)

Reference type:
Subject Reference
Current Version:
2019
Subject:
Science and technology, Life Sciences
Length:
82 words

... of numbers A diagrammatic expression of the numbers of individual organisms present at each trophic level of an ecosystem . It is the least useful of the 3 types of ecological pyramid since it makes no allowance for the different sizes and metabolic rates of organisms. Typically, it slopes more steeply than the other pyramids and may be inverted, e.g. when based on studies of temperate woodlands in summer. Compare pyramid of biomass ; pyramid of energy ; see also ecological pyramid...

pyramid of numbers

pyramid of numbers   Quick reference

A Dictionary of Zoology (4 ed.)

Reference type:
Subject Reference
Current Version:
2014
Subject:
Science and technology, Life Sciences
Length:
76 words

... of numbers A diagrammatic expression of the numbers of individual organisms present at each trophic level of an ecosystem . It is the least useful of the three types of ecological pyramid since it makes no allowance for the different sizes and metabolic rates of organisms. Typically it slopes more steeply than the other pyramids and may be inverted, e.g. when based on studies of temperate woodlands in summer. Compare pyramid of biomass ; pyramid of energy . ...

pyramid of numbers

pyramid of numbers   Quick reference

A Dictionary of Biology (8 ed.)

Reference type:
Subject Reference
Current Version:
2019
Subject:
Science and technology, Life Sciences
Length:
100 words
Illustration(s):
1

...pyramid of numbers A diagramatic representation of the numbers of animals found in an area at ascending trophic levels of a food chain (see illustration). Because only a small proportion of the energy taken in by an organism is converted to tissue and is thus available to consumers at the next trophic level, the number of organisms that can be supported at each level is generally much less than the number at the level that supplies its food (i.e. the level below). See also pyramid of biomass ; pyramid of energy . Pyramid of numbers for a woodland food...

pyramid of numbers

pyramid of numbers   Quick reference

A Dictionary of Geography (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

... of numbers ( ecological pyramid ) A diagram of a food chain which shows each trophic level as a horizontal bar, drawn in proportion to the biomass . There is a large fall from producers and primary consumers ; thereafter the decreases are smaller. The animals on the higher levels are generally larger and rarer than animals lower down the pyramid. See Kent (2000) PPG 24...

pyramid of numbers

pyramid of numbers   Quick reference

A Dictionary of Environment and Conservation (3 ed.)

Reference type:
Subject Reference
Current Version:
2017

... of numbers An ecological pyramid which shows the relationship between the number of individuals and their trophic level within a food web . The number of individuals usually decreases at each level; a large number of primary producers supports a small number of larger consumers...

pyramid of numbers

pyramid of numbers  

The characteristic decrease in the relative numbers of animals at each successively higher level in the food chain of a natural ecosystem (see illustration).Pyramid of numbers. A woodland food chain.
Medicine

Medicine   Reference library

An Oxford Companion to the Romantic Age

Reference type:
Subject Reference
Current Version:
2009
Subject:
History, modern history (1700 to 1945), Literature
Length:
3,985 words
Publisher:
Oxford University Press

...swelling sector of the British population. A consumer boom was in progress, and increased surplus income was going into all manner of goods and services, pleasures and household goods. The purchase of medical services was one manifestation of the growing prosperity of what has been called an early consumer society. The distinctive cultural formation of *spa towns operated precisely at this nexus of *consumerism [19] and medicalization. Historians of eighteenth-century medicine used to present a picture of an ordered, hierarchical, pyramidal medical...

Historic Churches

Historic Churches   Quick reference

David Hey

The Oxford Companion to Local and Family History (2 ed.)

Reference type:
Subject Reference
Current Version:
2009
Subject:
History, Local and Family History
Length:
5,420 words
Publisher:
Oxford University Press

...of oolitic limestone, especially in Lincolnshire and Rutland and adjacent counties, where the stone is suited to slender structures which are pierced by openings relieving an otherwise heavy appearance. The problem of fitting an eight‐sided spire onto a four‐sided tower was first solved by the use of broaches in the form of half‐pyramids at the joint. Broach spires were less successful in buildings where sandstone was used, e.g. in the Derbyshire Peak District, at Baslow, Hope, and Old Brampton. They date from the 13th and 14th centuries, before the use of...

Poverty

Poverty   Reference library

An Oxford Companion to the Romantic Age

Reference type:
Subject Reference
Current Version:
2009
Subject:
History, modern history (1700 to 1945), Literature
Length:
6,179 words
Publisher:
Oxford University Press

...system linked the destitute with a much broader constituency of the poor, the great mass of ‘inferiors’ at the bottom of the social pyramid. In this sense, poverty was usually taken for granted as a natural state requiring neither redress nor explanation beyond providential sanction, and the particular theory of economic value on which it rested often went unstated or was left vague. Agriculture was still a major source of income for the labouring classes, although it had not employed a majority of the population since the early eighteenth century [ see ...

Class

Class   Reference library

An Oxford Companion to the Romantic Age

Reference type:
Subject Reference
Current Version:
2009
Subject:
History, modern history (1700 to 1945), Literature
Length:
6,846 words
Publisher:
Oxford University Press

...*Thompson , author of Labour Rewarded ( 1827 ), debunked capital as a ‘ cabalistic word like church or state, or any other of those general terms which are invented by those who fleece the rest of mankind to conceal the hand that shears them’. John Gray ( 1799–1883 ), in A Lecture on Human Happiness ( 1825 ), made a robust evaluation of the utility of all existing groups in the population, which awarded top marks to the working classes, inverted the status pyramid of landed society, and challenged the rival middle-class vision of social value. ‘They...

14 Printed Ephemera

14 Printed Ephemera   Reference library

The Oxford Companion to the Book

Reference type:
Subject Reference
Current Version:
2010
Subject:
History, Social sciences
Length:
7,034 words
Publisher:
Oxford University Press
Illustration(s):
1

...seeking to construct a library and preserve its contents. One of the problems with the dialectic between ephemera and books, however, is that the book, though obviously distinct on the shelf, is itself an inherently insecure component of *print culture . The book as a form is usually placed at the top of a hierarchy of print, standing at the pinnacle of a pyramid of output that broadens out to the flat base of printed ephemera. However, this seems less than realistic, given the ephemeral nature of many books ( see survival rates ); moreover, their own...

19 The Electronic Book

19 The Electronic Book   Reference library

The Oxford Companion to the Book

Reference type:
Subject Reference
Current Version:
2010
Subject:
History, Social sciences
Length:
5,019 words
Publisher:
Oxford University Press
Illustration(s):
1

...model, selling one e-book at a time. A commercial avatar of PG appeared in Google Book Search, which promised vast amounts of content free to users, but its approach to copyrighted material proved controversial and slowed its full public release. 4 Characteristics Certain characteristics of e-books are unlikely to change. These are associated with the codex: *title , contributors, table of *contents , list of illustrations and tables, *front matter , *chapters , pages, page or paragraph numbers, *running heads , *book marks , *annotations , back...

age–sex pyramid

age–sex pyramid  

A set of two histograms set back to back on a vertical axis, depicting the numbers of the two sexes by age group. In many less developed countries the pyramid will have a very wide base; these are ...
pyramid of energy

pyramid of energy  

A diagrammatic representation of the amount of energy, measured in kilojoules per square metre per year (kJ m−2 yr−1), available at ascending trophic levels of a food chain in a particular habitat ...
pyramid of biomass

pyramid of biomass  

A diagrammatic representation of the amount of organic material (see biomass), measured in grams of dry mass per square metre (g m−2), found in a particular habitat at ascending trophic levels of a ...
ecological pyramid

ecological pyramid  

Graphical representation of the trophic structure and function of an ecosystem. The first trophic level, of producer organisms (usually green plants), forms the base of the pyramid, with succeeding ...
food chain

food chain  

In ecology (1), a hierarchy of organisms in which each is consumed as food by one or more of the ones above it. See also pyramid of numbers.
Miller indices

Miller indices  

One of the methods of notation devised to express the intercepts of crystal faces on crystallographic axes, proposed by W. H. Miller. The symbols h, k, and l represent whole numbers which are the ...

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