Observation of bumpus, Biology

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.

Posted Date: 4/6/2013 1:28:29 AM | Location : United States







Related Discussions:- Observation of bumpus, Assignment Help, Ask Question on Observation of bumpus, Get Answer, Expert's Help, Observation of bumpus Discussions

Write discussion on Observation of bumpus
Your posts are moderated
Related Questions
Define Complete Assessment for Dietary Management during Surgery? A complete assessment must include: Physical examination (anthropornetric measurements such as ideal/us

Surface area The rate of oxidation increases in direct proportion to the surface area of the lipid exposed to air. Furthermore, as surface - volume ratio is increased; a given

Equine viral arteritis Equine viral arteritis (EVA) is a highly contagious disease of equines and is caused by equine arteritis virus (EAV), a RNA virus belonging to the genus

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

how conjugation takes place in paramecium

Anti Platelet Drugs In the early years of CABG, patients used to be put on aspirin and persantin (Dipyridamole). Persantin is not routinely prescribed now. Aspirin dose can b

Define Diarrhoea problem of infants & preschoolers nutrition? We have just covered control and strategies in diarrhoea management in the above section. Crawling, unclean hands,

Soaking Soaking is an another inexpensive processing method, which does not require much technical know how, is commonly practiced for improving the palatability of chaffed cro

Q. Why is it not correct to assert that the DNA self- replicates? The DNA is not completely self-sufficient in its duplication process because the replication does not occur wi

Embryonic stem cells: can differentiate into all cell types of the specialized embryonic tissues when given sufficient and necessary stimulation for a specific cell type, e.g. Plu