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bare life

Italian philosopher Giorgio Agamben's concept for life that has been exposed to what he terms the structure of exception that constitutes contemporary biopower. The term originates in ...

Recapitulation

Recapitulation   Reference library

Encyclopedia of Evolution

Reference type:
Subject Reference
Current Version:
2005

...of von Baer and to the notion of divergence in the embryonic history. Then, in 1859 and following his reading of T. H. Huxley's translation of von Baer, Darwin also noted the importance of studying development for evidence of the animal's ancestral characteristics. After all, the divergence von Baer had discussed was remarkably similar to the descent by modification that Charles, Darwin envisioned. Darwin's epochal book On the Origin of Species appeared in 1859 . In it, Darwin carefully developed his new interpretation of animal life, emphasizing...

evergreen

evergreen   Quick reference

A Dictionary of Ecology (5 ed.)

Reference type:
Subject Reference
Current Version:
2015

...Applied to a tree or shrub that has persistent leaves, and whose crown is never wholly bare. Although the entire plant remains green throughout the year, each leaf has a limited life span, but is physically tougher and usually longer-lived than a deciduous leaf. Evergreen leaves have the advantage that where nutrients such as nitrogen are in short supply their longer life span allows a more efficient use of the limited...

Development

Development   Reference library

Encyclopedia of Evolution

Reference type:
Subject Reference
Current Version:
2005
Subject:
Science and technology, Life Sciences, Social sciences, Anthropology
Length:
11,771 words
Illustration(s):
2

...ideas for his evolutionary theories from von Baer. These included (1) a branching versus linear form of descent, (2) the idea that similar structures reveal common descent, and (3) the idea of using embryonic forms in classification. Because differences in adult form arise during development, von Baer's laws also led Darwin to see that the predictable similarities between the embryonic forms of different groups of organisms were strong support for his theory of evolution. Together, the ideas of von Baer, Schleiden and Schwann, and Darwin formed the...

History of Evolutionary Thought

History of Evolutionary Thought   Reference library

Encyclopedia of Evolution

Reference type:
Subject Reference
Current Version:
2005

...embryologist Karl Ernst von Baer ( 1792–1876 ), the naturalist Louis Agassiz ( 1807–1873 ), and the poet Goethe ( 1749–1832 ), science consisted in extracting general forms from the variety of patterns that are discernible in nature. For each natural group, an archetype exists, and the goal of science is to discover these archetypes. Just as there is the ideal fish, ideal vertebrate, and ideal plant, there is the ideal mineral. Each of these archetypes can be discovered by stripping away all accidental features to lay bare the essence of the thing....

Epigenesis and Preformationism

Epigenesis and Preformationism   Reference library

Encyclopedia of Evolution

Reference type:
Subject Reference
Current Version:
2005

...the problems. Microscopists could duplicate the work of one another, demonstrate their observations to others, and replicate their own work. Furthermore, the new instruments had much greater magnification and resolution. Thus, when the Prussian naturalist Karl Ernst von Baer published his monumental work on animal generation in 1828 , he was able to demonstrate with great microscopical acuity that the developing embryo emerged gradually from undifferentiated material in the female ovum. This work was continued by both Theodor Schwann and Matthias...

Amphibians

Amphibians   Reference library

Encyclopedia of Evolution

Reference type:
Subject Reference
Current Version:
2005
Subject:
Science and technology, Life Sciences, Social sciences, Anthropology
Length:
4,277 words
Illustration(s):
4

...Frogs have a dazzling array of evolutionary novelties associated with reproduction. Their diverse vocal signals of the males are used for mate advertisement and territorial displays. Parental care is highly developed in many lineages, including brooding of developing larvae on a bare back, in pouches on the back of females, in the vocal sacs of males, and in the stomach of females. Some females in some unrelated lineages of hylids and dendrobatids raise their tadpoles in the watery confines of a bromeliad axil and supply their own unfertilized eggs as food....

Karl Ernst von Baer

Karl Ernst von Baer  

(1792–1876)Estonian-born German biologist and embryologist. He studied medicine and comparative anatomy before becoming professor of zoology at Königsberg University in 1817. Ten years later he ...
Meleagrididae

Meleagrididae  

; class Aves, order Galliformes)A family of very large gamebirds which are dark, with a green and bronze sheen, and have a bare, blue or red head with wattles. The wings are barred with white, the ...
Meliphagidae

Meliphagidae  

; class Aves, order Passeriformes)A family of small to medium-sized, mainly green or grey-brown birds, some of which have patches of red, yellow, or white. Many have bare, wattled skin on the head, ...
Cracidae

Cracidae  

; class Aves, order Galliformes)A family of black, black and white, or brown, long-tailed, pheasant-like birds that have short, rounded wings and strong legs with large feet. Their bills are ...
Musophagidae

Musophagidae  

; class Aves, order Cuculiformes)A family of medium to large birds, some of which are brightly coloured with green, purple, and red, others a duller grey or brown. They have crested heads, bare skin ...
Philepittidae

Philepittidae  

; class Aves, order Passeriformes)A family which comprises two distinct genera, Philepitta (asities) and Neodrepanis (false sunbirds). Asities are small, plump, short-tailed birds that have a ...
cere

cere  

In birds, an area of skin at the base of the upper mandible, surrounding the nostrils, that is found in Falconiformes, in which it is bare, in Psittaciformes, in which it is usually feathered, and in ...
wattle

wattle  

In birds, a bare, fleshy area of skin, often highly coloured and pendulous, that usually hangs from the gape, around the eye, or on the throat. Wattles are used mainly in display and some are moulted ...
New World Vultures

New World Vultures  

New and old world vultures are similar in appearance, both having the hooked bill, bare head and neck, and large, broad wings that suit them to the scavenging way of ...
biogenetic law

biogenetic law  

The early stages of development in animal species resemble one another, the species diverging more and more as development proceeds. The law was formulated by the embryologist E. K. von Baer ...
recapitulation of phylogeny

recapitulation of phylogeny  

A theory, due to E. H. Haeckel, asserting that ontogeny (the development of the individual) recapitulates or reflects the phylogeny (the evolutionary history of the individual). The theory as such ...
fugitive species

fugitive species  

A species that is able to coexist with a competitively superior species due to its better dispersal capabilities. The fugitive species is quicker to exploit any vacant patches in the environment that ...
hollow phase

hollow phase  

A stage in the cyclical pattern of vegetation change in grassland, at which a hollow forms from the erosion of an old grass hummock during the degenerate phase. Colonization of the bare soil by grass ...
Gruidae

Gruidae  

; class Aves, order Gruiformes)A family of large, long-legged, long-necked, white, grey, or brown birds in which the head has areas of bare red skin or plumes, the bill is straight and medium to ...

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