scholarly journals Data for the problem of evolution in man. VI.—A first study of the correlation of the human skull

1901 ◽  
Vol 67 (435-441) ◽  
pp. 333-337
Keyword(s):  
Size Variation ◽  
Human Skull ◽  
University College ◽  
Local Race

The substance of this paper was a thesis for the London D. Sc. degree; it was shown to Professor Pearson, at whose suggestion considerable modifications were made, and a revision undertaken with a view to publication. In order to deal exactly with the problem of evolution in man it is necessary to obtain in the first place a quantitative appreciation of the size, variation, and correlation of the chief characters in man for a number of local races. Several studies of this kind have been already undertaken at University College. These fall into two classes, (i) those that deal with a variety of characters in one local race, and (ii) those which study the comparative value of the constants from a variety of races.

scholarly journals V. Data for the problem of evolution in man.—VI. A first study of the correlation of the human skull

1901 ◽  
Vol 196 (274-286) ◽  
pp. 225-264 ◽  
Keyword(s):  
Large Series ◽  
Human Skull ◽  
Quantitative Theory ◽  
Modern Methods ◽  
The Subject ◽  
The Many ◽  
Shoulder Blade ◽  
Made In ◽  
Local Race

(1.) The reconstruction of an organism from a knowledge of some only of its parts is a problem which has occupied the attention of biologists for many years past. Cuvier was the first to introduce in his Discours sur les Révolutions de la Surface du Globe,’ 1812, the idea of correlation. He considered that a knowledge of the size of a shoulder blade, leg, or arm might make it possible to reconstruct the whole individual to which the bone had belonged. The conception was taken up by Owen, but has fallen into discredit owing to the many errors made in attempts from a wide but only qualitative knowledge of the skeleton, to reconstruct forms the appreciation of which depends really on quantitative measurement and an elaborate quantitative theory. Such a theory having now been developed, and anatomists having provided large series of measurements, it has become possible to reconsider the problem on a sounder basis, and to determine more closely the limits under which our modern methods may be safely applied. The three fundamental problems of the subject are: (i.) The reconstruction of an individual, of whom one or more organs only are known, when a series of organs for individuals of the same local race have been measured and correlated.

Elevated nest predation risk promotes offspring size variation in birds with prolonged parental care.

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Predation Risk ◽  
Reproductive Cycle ◽  
Perceived Risk ◽  
Nest Predation ◽  
Bird Species ◽  
Size Variation ◽  
Egg Laying ◽  
Offspring Size ◽  
Natural Predation ◽  
Risk Spreading

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.

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