Observation of bumpus, Biology

Assignment Help:

An interesting observation made by an American biologist H.C. Bumpus (1899) provides a good explanation for normalising selection. Bumpus collected some 136 injured house sparrows after a severe snow and sleet storm with high winds at Woods hole. Of these birds 64 died, resulting in two groups of sparrows, those that were killed by the storm and the ones that survived. Bumpus, made measurements of a number of randomly chosen traits such as wing length, wing span, tarsus length etc and found that those that were killed by the storm had measurements which fell at the ends of the bell shaped curve. In other words, birds which had either mean or close to the rnean measurements were the ones to survive. Normalising selection generally eliminates during a catastrophe or a stressful situation individuals whose traits vary markedly from the mean values. By way of interpreting Bumpus's observations, it could be said that the birds which were blown down easily by the winds had either their wings too long for their body weight and therefore presented a larger surface area or they had too short wings for their body size and therefore could not fly against strong winds. Prjor to the catastrophe the range of individual measurements was larger as compared to the range of measurements that survived the catastroihe. Every catastrophe may narrow down the variability of the population thereby weeding out suboptimal genotypes.


Related Discussions:- Observation of bumpus

Define requirements of iodine during pregnancy period, Define requirements ...

Define requirements of Iodine during pregnancy period? You would be already aware that maternal iodine deficiency leads to cretinism in the off spring. Hence, the material diet

What are primary mediators, Primary mediators are those, which are produced...

Primary mediators are those, which are produced before degranulation. These primary mediators are stored in granules. Some of the primary mediators are histamine, heparin, protease

Difference between cerebrum and brain, Q. What is the difference between ce...

Q. What is the difference between cerebrum and brain? What are the major parts of these structures? The concept of brain or encephalon comprehends the cerebrum mostly referred

Psychology, Psychology : This is the study of human mind. On other words Ps...

Psychology : This is the study of human mind. On other words Psychology is the science of behavior or mental processes. Its immediate aim is to understand the individuals or groups

Growth and development, details and terms used in growth and development?

details and terms used in growth and development?

Epithelial tissues., function , structure and lo of location of germinal e...

function , structure and lo of location of germinal epithelium

How is the circulatory system of birds characterized, How is the circulator...

How is the circulatory system of birds characterized? Birds, as every vertebrate, have a closed circulatory system. The heart is same to the mammalian heart, having four chambe

Malthus theory of human population growth, MA L THU S THEORY OF HUMAN PO...

MA L THU S THEORY OF HUMAN POPULATION GROWTH - Malthus put forward in 1778. 1.       Population grows in geometrical ratio, where as the means grow in arithmetical ratio.

What are the factors affecting osseointegration, Factors Affecting Osseoint...

Factors Affecting Osseointegration a) Biocompatibility of the material b) Surgical technique- c) Bone density - d) Occlusal load e) Infection f) Implant surface

Define counter stain - staining technique, Define Counter Stain - Staining ...

Define Counter Stain - Staining Technique? Finally, the smear is counter stained with a simple basic dye different in colour from crystal violet. Safranin is the most commonly

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd