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.
What is the destination of the branchial clefts in humans? In humans the branchial clefts situated in the anterior region of the pharynx (also called as pharyngeal clefts) are
Q. What are the three major cell types that form the osseous tissue? What are their functions? The three major cell types of the osseous tissue are the osteocytes, the osteobla
What is frog central nervous system Consider Neuron B in the frog central nervous system whose plasma membrane has a newly discovered ligand-gated ionotropic receptor, named th
Explain about the Thiamin - Vitamin B or aneurin? Thiamin is one of the earliest recognized vitamins. The chemical structure of thiamine was established by Williams in 1936. Th
Q. Why do ribosomes move along mRNA during translation? During translation the ribosome always exposes two mRNA codons to be translated by moving along the mRNA, when a peptide
The A and B antigens in humans may be found in water-soluble form in secretions, including saliva, of some individuals (Se/Se and Se/se) but not in others (se/se). The population t
Specific Causes of Parental Anxiety Some of the factors that increase their anxiety include following: 1) Fear of the strange environment in the hospital 2) Fear
Q. What is the name of the terminal portion of the axon? The terminal portion of the axon is called as presynaptic membrane Through, this membrane neurotransmitters are release
Explain the Hydrophobic Grid Membrane Filter (HGMF)? It is also used to enumerate microorganisms from a variety of food samples. By using this method, organisms as few as 10 ce
Define absorption, transport and excretion of magnesium? Magnesium absorption to some extent is similar to that of Ca. Absorption of Mg occurs throughout the small intestine, a
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