Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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.
Actions of Estrogens The most general effect of the estrogens is to promote tissue growth. It is more pronounced in the accessory sex tissues. Estrogens stimulate cell divi
what is the mode of nutrition in cow
Some biologists prefer to categorize brown, red, and some green algae as plants rather than protists. What characteristics of these algae support like classification? Brown and
What is the effect of increased temperature on a non enzyme catalyzed reaction? What are the effects of increased temperature on an enzyme catalyzed reaction?
PHYLUM PROTOZOA Definition and Introduction All unicellular ( or acellular ) eukaryotic animals. Most primitive (Gr. Protos = first=zoon= animals ) organisms
Q. What is the neuromuscular synapse? Neuromuscular synapse is the structure through which the neural impulse passes from the axon of a motor neuron to the muscle cell. This st
Give an example of how two organisms are interdependent.
An hypothesis for the extinction of the dinosaurs is that the earth had been hit by a gigantic meteor that caused the death of those big reptiles. In that case the entire genetic p
Most bacteria are anaerobic. If a bacterium were to produce the same amount of ATP within a minute as a cell extracted from your skeletal muscle, what would that bacterium have to
How is HIV transmitted? What is the disease caused by this virus? HIV (human immunodeficiency virus) is supposed to be transmitted by blood, semen, maternal milk and vaginal se
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd