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 role of leptin in controlling gene expression, Define role of Leptin...

Define role of Leptin in controlling gene expression? Leptin is a protein product (containing 167 amino acids) of the ob gene expressed exclusively in the adipose tissue. This

Name mimicry by which insect mimics insec for protection, From the followin...

From the following, name the type of mimicry by which a palatable, acceptable insect mimics an unfavorable, noxious insec for protection. a) Batesian mimicry (pron: BATE-see-an

Bone marrow transplant, BON E MARROW TRANSPLANT - It is transplante...

BON E MARROW TRANSPLANT - It is transplanted to treat leukemia. Here, graft itself causes immune rejection. Before transplant, the recipient's bone marrow cells, incl

Which cannot react with dehydration reaction, Which of the following pairs ...

Which of the following pairs of functional groups CANNOT react with each other by a dehydration reaction? Select one: a. Carboxyl;Hydroxyl b. Carboxyl;Sulfhydryl c. Pho

Define disadvantages of using the plate counts method, Define Disadvantages...

Define Disadvantages of Using the Plate Counts Method? 1. It takes time, usually 24 hours or more is required to obtain visible colonies. 2. Microbial count obtained depends

Can you explain yersinia enterocolitica gastroenteritis, Q. Can you explain...

Q. Can you explain Yersinia Enterocolitica Gastroenteritis? Yersiniosis is an infectious disease caused by a bacterium of the genus Yersinia. Most human illness is caus

Explain the food preparation and cooling - canning, Explain the Food prepar...

Explain the Food preparation and Cooling - Canning? Food preparation - Preparation methods will change with the type of food. For fruit, cutting to size, washing, grading, peel

Define the word glycemic, Glycemic or sugar control The control of bloo...

Glycemic or sugar control The control of blood sugar is one of the most important factors of good care for the diabetic patient. It has been shown that good glycemic or sugar c

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