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

Infective endocarditis, Infective Endocarditis :  All patients with prosth...

Infective Endocarditis :  All patients with prosthetic valve come under the high-risk category for endocarditis. They need prophylactic antibiotics if any procedure, which is like

Food chain, Food chain is the simplest representation of energy flow in th...

Food chain is the simplest representation of energy flow in the community. At the base is energy stored in the plants, which are eaten by the small organisms, which in turn are ea

Why should posterior wall preffered during surgery, Why should Posterior wa...

Why should Posterior wall preffered during surgery Posterior wall should not be perforated during surgery. This limits bleeding from the pterygoid plexus or branches of the max

Ecosystems, what is biodiversity?where are ecosystems with the highest biov...

what is biodiversity?where are ecosystems with the highest bioversityfound?

Why is this area more vulnerable to damage than others, A small family was ...

A small family was traveling in the car when a minor accident happened. The children in the back seats were wearing lap belts, but still sustained numerous bruises about the abdome

Compare and contrast enantiomers in relation to sugars, Compare and contras...

Compare and contrast enantiomers, epimers, and anomers, specifically in relation to sugars.

Diffrence between fish epidermis and amphibian epidermis, Q. How different ...

Q. How different is the fish epidermis from the amphibian epidermis? The fish epidermis is very contains and thin mucus-secreting cells the fish skin doesn't present keratin, t

Corpus luteum in human females.., what is the fate of corpus luteum if egg...

what is the fate of corpus luteum if egg gets fertilised ?

Limitations of five-kingdom classification, Limitations of Five-Kingdom Cla...

Limitations of Five-Kingdom Classification As already pointed out, each system of classification has its own limitations. The two-kingdom system has outlived its usefulness as

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