Thadasthu KR IRS 29422 On Fri, 29 Apr 2022 at 10:57, Markendeya Yeddanapudi < [email protected]> wrote:
> Respected Rajaram Sir, > Every post of yours,elevates the standard of a post.The usually wonderful > post of Sri Gopalakrishnan,here has been elevated to the realm of deep > contemplation and insights.Hope the beauty of the posts will not be damaged > by meaningless misunderstanding. > YM > > > On Fri, Apr 29, 2022 at 10:38 AM Rajaram Krishnamurthy < > [email protected]> wrote: > >> Pranam >> Q10 Main Theories of Evolution >> >> So main theories of evolution are: >> >> (I) Lamarckism or Theory of Inheritance of Acquired characters. >> >> (II) Darwinism or Theory of Natural Selection. >> >> (III) Mutation theory of De Vries. >> >> (IV) Neo-Darwinism or Modern concept or Synthetic theory of evolution. >> >> I. Lamarckism: >> >> It is also called “Theory of inheritance of acquired characters” and was >> proposed by a great French naturalist, Jean Baptiste de Lamarck (Fig. 7.34) >> in 1809 A.D. in his famous book “Philosphic Zoologique”. This theory is >> based on the comparison between the contemporary species of his time to >> fossil records. >> >> Jean Baptiste de Lamarck >> >> His theory is based on the inheritance of acquired characters which are >> defined as the changes (variations) developed in the body of an organism >> from normal characters, in response to the changes in environment, or in >> the functioning (use and disuse) of organs, in their own life time, to >> fulfill their new needs. Thus Lamarck stressed on adaptation as means of >> evolutionary modification. >> >> A. Postulates of Lamarckism: >> >> Lamarckism is based on following four postulates: >> >> 1. New needs: >> >> Every living organism is found in some kind of environment. The changes >> in the environmental factors like light, temperature, medium, food, air >> etc. or migration of animal lead to the origin of new needs in the living >> organisms, especially animals. To fulfill these new needs, the living >> organisms have to exert special efforts like the changes in habits or >> behaviour. >> >> 2. Use and disuse of organs: >> >> >> >> The new habits involve the greater use of certain organs to meet new >> needs, and the disuse or lesser use of certain other organs which are of no >> use in new conditions. This use and disuse of organs greatly affect the >> form, structure and functioning of the organs. >> >> Continuous and extra use of organs make them more efficient while the >> continued disuse of some other organs lead to their degeneration and >> ultimate disappearance. So, Lamarckism is also called “Theory of use and >> disuse of organs.” >> >> So the organism acquires certain new characters due to direct or indirect >> environmental effects during its own life span and are called Acquired or >> adaptive characters. >> >> 3. Inheritance of acquired characters: >> >> Lamarck believed that acquired characters are inheritable and are >> transmitted to the offsprings so that these are born fit to face the >> changed environmental conditions and the chances of their survival are >> increased. >> >> 4. Speciation: >> >> Lamarck believed that in every generation, new characters are acquired >> and transmitted to next generation, so that new characters accumulate >> generation after generation. After a number of generations, a new species >> is formed. >> >> So according to Lamarck, an existing individual is the sum total of the >> characters acquired by a number of previous generations and the speciation >> is a gradual process. >> >> Summary of four postulates of Lamarckism: >> >> 1. Living organisms or their component parts tend to increase in size. >> >> 2. Production of new organ is resulted from a new need. >> >> 3. Continued use of an organ makes it more developed, while disuse of an >> organ results in degeneration. >> >> >> >> 4. Acquired characters (or modifications) developed by individuals during >> their own lifetime are inheritable and accumulate over a period of time >> resulting a new species. >> >> B. Evidences in favour of Lamarckism: >> >> 1. Phylogenetic studies of horse, elephant and other animals show that >> all these increase in their evolution from simple to complex forms. >> >> 2. Giraffe (Fig. 7.35) >> >> Development of present day long-necked and long fore-necked giraffe from >> deer-like ancestor by the gradual elongation of neck and forelimbs in >> response to deficiency of food on the barren ground in dry deserts of >> Africa. These body parts were elongated so as to eat the leaves on the tree >> branches. This is an example of effect of extra use and elongation of >> certain organs. >> >> Stages in the Evolution of Present Day Giraffe >> >> 3. Snakes: >> >> Development of present day limbless snakes with long slender body from >> the limbed ancestors due to continued disuse of limbs and stretching of >> their body to suit their creeping mode of locomotion and fossorial mode of >> living out of fear of larger and more powerful mammals. It is an example of >> disuse and degeneration of certain organs. >> >> 4. Aquatic birds: >> >> Development of aquatic birds like ducks, geese etc. from their >> terrestrial ancestors by the acquired characters like reduction of wings >> due to their continued disuse, development of webs between their toes for >> wading purposes. >> >> These changes were induced due to deficiency of food on land and severe >> competition. It is an example of both extra use (skin between the toes) and >> disuse (wings) of organs. >> >> 5. Flightless birds: >> >> Development of flightless birds like ostrich from flying ancestors due to >> continued disuse of wings as these were found in well protected areas with >> plenty of food. >> >> 6. Horse: >> >> The ancestors of modem horse (Equus caballus) used to live in the areas >> with soft ground and were short legged with more number of functional >> digits (e.g. 4 functional fingers and 3 functional toes in Dawn >> horse-Eohippus). These gradually took to live in areas with dry ground. >> This change in habit was accompanied by increase in length of legs and >> decrease in functional digits for fast running over hard ground. >> >> C. Criticism of Lamarckism: >> >> A hard blow to Lamarckism came from a German biologist, August Weismann >> who proposed the “Theory of continuity of germplasm” in 1892 A.D. This >> theory states that environmental factors do affect only somatic cells and >> not the germ cells. >> >> As the link between the generations is only through the germ cells and >> the somatic cells are not transmitted to the next generation so the >> acquired characters must be lost with the death of an organism so these >> should have no role in evolution. He suggested that germplasm is with >> special particles called “ids” which control the development of parental >> characters in offsprings. >> >> Weismann mutilated the tails of mice for about 22 generations and allowed >> them to breed, but tailless mice were never born. Pavlov, a Russian >> physiologist, trained mice to come for food on hearing a bell. He reported >> that this training is not inherited and was necessary in every generation. >> Mendel’s laws of inheritance also object the postulate of inheritance of >> acquired characters of Lamarckism. >> >> Similarly, boring of pinna of external ear and nose in Indian women; >> tight waist, of European ladies circumcising (removal of prepuce) in >> certain people; small sized feet of Chinese women etc are not transmitted >> from one generation to another generator. >> >> Eyes which are being used continuously and constantly develop defects >> instead of being improved. Similarly, heart size does not increase >> generation after generation though it is used continuously. >> >> Presence of weak muscles in the son of a wrestler was also not explained >> by Lamarck. Finally, there are a number of examples in which there is >> reduction in the size of organs e.g. among Angiosperms, shrubs and herbs >> have evolved from the trees. >> >> So, Lamarckism was rejected. >> >> D. Significance: >> >> 1. It was first comprehensive theory of biological evolution. >> >> 2. It stressed on adaptation to the environment as a primary product of >> evolution. >> >> Neo-Lamarckism: >> >> Long forgotten Lamarckism has been revived as Neo-Lamarckism, in the >> light of recent findings in the field of genetics which confirm that >> environment does affect the form, structure; colour, size etc. and these >> characters are inheritable. >> >> Main scientists who contributed in the evolution of Neo-Lamarckism are: >> French Giard, American Cope, T.H. Morgan, Spencer, Packard, Bonner, Tower, >> Naegali, Mc Dougal, etc. Term neo-Lamarckism was coined by Alphaeus S. >> Packard. >> >> Neo-Lamarckism states: 1. Germ cells may be formed from the somatic >> cells indicating similar nature of chromosomes and gene make up in two cell >> lines e.g.(a) Regeneration in earthworms.(b) Vegetative propagation in >> plants like Bryophyllum (with foliar buds).(c) A part of zygote >> (equipotential egg) of human female can develop into a complete baby >> (Driesch). >> >> 2. Effect of environment on germ cells through the somatic cells e.g. >> Heslop Harrison found that a pale variety of moth, Selenia bilunaria, when >> fed on manganese coated food, a true breeding melanic variety of moth is >> produced. >> >> 3. Effect of environment directly on germ cells. Tower exposed the young >> ones of some potato beetles to temperature fluctuation and found that >> though beetles remained unaffected with no somatic change but next >> generation had marked changes in body colouration. >> >> Muller confirmed the mutagenic role of X-rays on Drosophila while C. >> Auerbach et., al. confirmed the chemical mutagens (mustard gas vapours) >> causing mutation in Drosophila melanogaster, so neo-Lamarckism proved: >> >> (a) Germ cells are not immune from the effects of the environment. >> >> (b) Germ cells can carry somatic changes to next progeny (Harrison’s >> experiment). >> >> (c) Germ cells may be directly affected by the environmental factors >> (Tower’s experiment). >> >> Difference between Lamarckism and Neo-Lamarckism >> >> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx >> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx { Darwin not taken >> heer} >> >> III. Mutation Theory of Evolution: >> >> The mutation theory of evolution was proposed by a Dutch botanist, Hugo >> de Vries (1848-1935 A.D.) (Fig. 7.38) in 1901 A.D. in his book entitled >> “Species and Varieties, Their Origin by Mutation”. He worked on evening >> primrose (Oenothera lamarckiana). >> >> Hugo de Vries >> >> A. Experiment: >> >> Hugo de Vries cultured O. lamarckiana in botanical gardens at Amsterdam. >> The plants were, allowed to self pollinate and next generation was >> obtained. The plants of next generation were again subjected to self >> pollination to obtain second generation. Process was repeated for a number >> of generations. >> >> B. Observations: >> >> Majority of plants of first generation were found to be like the parental >> type and showed only minor variations but 837 out of 54,343 members were >> found to be very different in characters like flower size, shape and >> arrangement of buds, size of seeds etc. These markedly different plants >> were called primary or elementary species. >> >> A few plants of second generation were found to be still more different. >> Finally, a new type, much longer than the original type, called O. gigas, >> was produced. He also found the numerical chromosomal changes in the >> variants (e.g. with chromosome numbers 16, 20, 22, 24, 28 and 30) upto 30 >> (Normal diploid number is 14). >> >> >> >> C. Conclusion: >> >> 1. The evolution is a discontinuous process and occurs by mutations (L. >> mutate = to change; sudden and inheritable large differences from the >> normal and are not connected to normal by intermediate forms). Individuals >> with mutations are called mutants. >> >> 2. Elementary species are produced in large number to increase chances of >> selection by nature. >> >> 3. Mutations are recurring so that the same mutants appear again and >> again. This increases the chances of their selection by nature. >> >> 4. Mutations occur in all directions so may cause gain or loss of any >> character. >> >> 5. Mutability is fundamentally different from fluctuations (small and >> directional changes). >> >> So according to mutation theory, evolution is a discontinuous and jerky >> process in which there is a jump from one species to another so that new >> species arises from pre-existing species in a single generation >> (macrogenesis or saltation) and not a gradual process as proposed by >> Lamarck and Darwin. >> >> D. Evidences in favour of Mutation theory: >> >> 1. Appearance of a short-legged sheep variety, Ancon sheep (Fig. 7.39), >> from long-legged parents in a single generation in 1791 A.D. It was first >> noticed in a ram (male sheep) by an American farmer, Seth Wright. >> >> Appearance of Short Leggard Ancon Sheep Mutant >> >> 2. Appearance of polled Hereford cattle from horned parents in a single >> generation in 1889. >> >> 3. De Vries observations have been experimentally confirmed by McDougal >> and Shull in America and Gates in England. >> >> 4. Mutation theory can explain the origin of new varieties or species by >> a single gene mutation e.g. Cicer gigas, Nuval orange. Red sunflower, >> hairless cats, double- toed cats, etc. >> >> 5. It can explain the inheritance of vestigial and over-specialized >> organs. >> >> >> >> 6. It can explain progressive as well as retrogressive evolution. >> >> E. Evidences against Mutation theory: >> >> 1. It is not able to explain the phenomena of mimicry and protective >> colouration. >> >> 2. Rate of mutation is very low, i.e. one per million or one per several >> million genes. >> >> 3. Oenothera lamarckiana is a hybrid plant and contains anamolous type of >> chromosome behaviour. >> >> 4. Chromosomal numerical changes as reported by de Vries are unstable. >> >> 5. Mutations are incapable of introducing new genes and alleles into a >> gene pool. >> >> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx >> >> IV. Neo-Darwinism or Modern Concept or Synthetic Theory of Evolution: >> >> The detailed studies of Lamarckism, Darwinism and Mutation theory of >> evolution showed that no single theory is fully satisfactory. Neo-Darwinism >> is a modified version of theory of Natural Selection and is a sort of >> reconciliation between Darwin’s and de Vries theories. >> >> Modern or synthetic theory of evolution was designated by Huxley (1942). >> It emphasises the importance of populations as the units of evolution and >> the central role of natural selection as the most important mechanism of >> evolution. >> >> The scientists who contributed to the outcome of Neo-Darwinism were: J.S. >> Huxley, R.A. Fischer and J.B.S. Haldane of England; and S. Wright, Ford, >> H.J. Muller and T. Dobzhansky of America. >> >> A. Postulates of Neo-Darwinism: >> >> 1. Genetic Variability: >> >> Variability is an opposing force to heredity and is essential for >> evolution as the variations form the raw material for evolution. The >> studies showed that the units of both heredity and mutations are genes >> which are located in a linear manner on the chromosomes. >> >> >> >> Various sources of genetic variability in a gene pool are: >> >> (i) Mutations: >> >> These are sudden, large and inheritable changes in the genetic material. >> On the basis of amount of genetic material involved, mutations are of three >> types: >> >> (a) Chromosomal aberrations: >> >> These include the morphological changes in the chromosomes without >> affecting the number of chromosomes. These result changes either in the >> number of genes (deletion and duplication) or in the position of genes >> (inversion). >> >> These are of four types: >> >> 1. Deletion (Deficiency) involves the loss of a gene block from the >> chromosome and may be terminal or intercalary. >> >> 2. Duplication involves the presence of some genes more than once, called >> the repeat. It may be tandem or reverse duplication. >> >> 3. Translocation involves transfer of a gene block from one chromosome to >> a non-homologous chromosome and may be simple or reciprocal type. >> >> 4. Inversion involves the rotation of an intercalary gene block through >> 180° and may be paracentric or pericentric. >> >> (b) Numerical chromosomal mutations: >> >> These include changes in the number of chromosomes. These may be euploidy >> (gain or loss of one or more genomes) or aneuploidy (gain or loss of one or >> two chromosomes). Euploidy may be haploidy or polyploidy. >> >> Among polyploidy, tetraploidy is most common. Polyploidy provides greater >> genetic material for mutations and variability. In haploids, recessive >> genes express in the same generation. >> >> Aneuploidy may be hypoploidy or hyperploidyl Hypoploidy may be monosomy >> (loss of one chromosome) or nullisomy (loss of two chromosomes). >> Hyperploidy may be trisomy (gain of one chromosome) or tetrasomy (gain of >> two chromosomes). >> >> >> >> (c) Gene mutations (Point mutations): >> >> These are invisible changes in chemical nature (DNA) of a gene and are of >> three types: >> >> 1. Deletion involves loss of one or more nucleotide pairs. >> >> 2. Addition involves gain of one or more nucleotide pairs. >> >> 3. Substitution involves replacement of one or more nucleotide pairs by >> other base pairs. These may be transition or transversion type. >> >> These changes in DNA cause the changes in the sequence of amino acids so >> changing the nature of proteins and the phenotype. >> >> (ii) Recombination of genes: >> >> Thousands of new combinations of genes are produced due to crossing over, >> chance arrangement of bivalents at the equator during metaphase – I and >> chance fusion of gametes during fertilization. >> >> (iii) Hybridization: >> >> It involves the interbreeding of two genetically different individuals to >> produce ‘hybrids’. >> >> (iv) Physical mutagens (e.g. radiations, temperature etc.) and chemical >> mutagens (e.g. nitrous acid, colchicine, nitrogen mustard etc.). >> >> (v) Genetic drift: >> >> It is the elimination of the genes of some original characteristics of a >> species by extreme reduction in a population due to epidemics or migration >> or Sewell Wright effect. >> >> The chances of variations are also increased by non-random mating. >> >> 2. Natural Selection: >> >> Natural selection of Neo- Darwinism differs from that of Darwinism that >> it does not operate through “survival of the fittest” but operates through >> differential reproduction and comparative reproductive success. >> >> Differential reproduction states that those members, which are best >> adapted to the environment, reproduce at a higher rate and produce more >> offsprings than those which are less adapted. So these contribute >> proportionately greater percentage of genes to the gene pool of next >> generation while less adapted individuals produce fewer offsprings. >> >> If the differential reproduction continues for a number of generations, >> then the genes of those individuals which produce more offsprings will >> become predominant in the gene pool of the population as shown in Fig. 7.40. >> >> Spread of Genetic Variability by Differential Reproduction >> >> Due to sexual communication, there is free flow of genes so that the >> genetic variability which appears in certain individuals, gradually spreads >> from one deme to another deme, from deme to population and then on >> neighbouring sister populations and finally on most of the members of a >> species. So natural selection causes progressive changes in gene >> frequencies, ‘i.e. the frequency of some genes increases while the >> frequency of some other genes decreases. >> >> Which individuals produce more offsprings? >> >> (i) Mostly those individuals which are best adapted to the environment. >> >> (ii) Whose sum of the positive selection pressure due to useful genetic >> variability is more than the sum of negative selection pressure due to >> harmful genetic variability? >> >> (iii) Which have better chances of sexual selection due to development of >> some bright coloured spots on their body e.g. in many male birds and fish. >> >> (iv) Those who are able to overcome the physical and biological >> environmental factors to successfully reach the sexual maturity. >> >> So natural selection of Neo-Darwinism acts as a creative force and >> operates through comparative reproductive success. Accumulation of a number >> of such variations leads to the origin of a new species. >> >> 3. Reproductive isolation: >> >> Any factor which reduces the chances of interbreeding between the related >> groups of living organisms is called an isolating mechanism. Reproductive >> isolation is must so as to allow the accumulation of variations leading to >> speciation by preventing hybridization. >> >> In the absence of reproductive isolation, these variants freely >> interbreed which lead to intermixing of their genotypes, dilution of their >> peculiarities and disappearance of differences between them. So, >> reproductive isolation helps in evolutionary divergence. KR IRS 29422 >> >> >> >> On Fri, 29 Apr 2022 at 04:59, 'gopala krishnan' via iyer123 < >> [email protected]> wrote: >> >>> *CULTURAL QA 04-2022-29* >>> >>> *BEING A COMPILATION THERE MAY BE ERRORS* >>> >>> Q1 Can I close the windows and doors of the air conditioner >>> room of my house with paper so that it cools down quickly? >>> >>> A1 Gopala Krishnan , former Assistant General Manager >>> 1996-2004 at Department of Telecom (1966-2004)Answered just now >>> >>> You may close all doors and windows *except one window panel partially >>> opened. I*f any problem occurs in the AC unit, there will be no >>> suffocation. There are problems by pasting even transparent paper in the >>> window panes. If anything occur in the room, from outside nothing will be >>> visible. *The slightly quicker cooling effect is there b*y putting >>> stickers, but just like *stickers are banned in vehicles, any banning >>> can be in window panes also. Hotels it is banned I know.* >>> >>> Q2 What is the 'Diamond Crossing' in Nagpur? >>> >>> A2 Steven World Geo Politics. Apr 23 >>> >>> Diamond crossing is the junction in Nagpur where a particular *diamond >>> shape ( square type) railway tracks intersects each other* one from >>> North to South other from is East to West of India. >>> >>> This diamond is considered as centre point of india. >>> >>> Q3 Why do lawyers charge so much per hour? >>> >>> A3 Steven Haddock LL.B. degree, 25 years in litigation, >>> administrative law, collections, bankrupty and professional regulationTue >>> >>> Law practices carry an immense amount of overhead - expenses you can’t >>> avoid even if you’re doing next to no work. >>> >>> Do you have a trust account? You better not let your spouse do your >>> books unless you want a visit from the regulatory authority. You have to >>> have someone trained to reconcile trust accounts, plus specialized >>> accounting software. This isn’t a job for Quickbooks. >>> >>> *You will need office space to meet with clients and keep records, of >>> which there are strict rules what* you have to keep and how long you >>> have to keep them. A box in your garage won’t cut it. >>> >>> *There are annual fees for the bar and for insurance.* The lawyer I >>> worked with joked that the increase in his fees one year was larger than >>> what professional engineers pay for the entire year. >>> >>> *You will need access to legal research facilities, which charge a lot. >>> Thompson Rogers/Reuters* bought LEXIS for a reason - it’s extremely >>> profitable. *You may also need staff, computers, scanners, >>> photocopiers, and you have outside contractors* whose fees you can’t >>> always charge to your clients. >>> >>> *Oh, and speaking of clients, sometimes they don’t pay those fees.* >>> >>> Q4 Who pays for dinner after a funeral? >>> >>> A4 Bhuvana Rameshwar married for three decades Tue >>> >>> If there are local people attending a funeral they leave immediately >>> *without >>> a good bye*. Walking away quietly after the funeral ceremony is common >>> in India. They may however come over after bathing. >>> >>> This is the custom among Hindu Indians. But if the funeral is in a far >>> away town or city people stay back, bathe and are served simple food >>> *usually >>> bought from restaurants.* >>> >>> *Usually the brother /elder sister of the dead person, the inlaw’s >>> family or the parents of the son in law or daughter in law help out with >>> these expenses as a norm.* This is also the most they can in a funeral >>> house. If nobody sometimes friends too pool in to help especially if the >>> adult children are not earning or are not married with inlaws. >>> >>> Q5 Is Powdered laundry detergent work better than liquids? >>> >>> A5 Gopala Krishnan, former Assistant General Manager >>> 1996-2004 at Department of Telecom (1966-2004)Answered just now >>> >>> Detergent as Liquids is a late comer. Even when automatic washing >>> machines appeared in India, there were only detergent powders. *Detergent >>> liquids can quickly work on clothes*. It’s absorbing time to water is >>> less. Even for daily washing we can see the effect before our eyes. Take >>> half bucket of water and add 2 teaspoons of detergent liquid. Mix with hand >>> . *Add one or two soiled clothes like dhoti ,towel etc.* After one >>> minute just take out the clothes. You can find light brown( dirty water) in >>> the bucket. If you squeeze more dirt if there will go quickly. Wash the >>> clothes again in fresh water. Find the appearance of clothes >>> >>> Q6 What leads to ice formation in my air conditioner? How >>> can I prevent it? >>> >>> A6 Ravi Raj, Air conditioning Answered Oct 24, 2015 >>> >>> Fan problems. *The evaporator unit’s fan is responsible for keeping the >>> coils above the freezing point so that the condensation on the coils cannot >>> freeze. A faulty fan* that spins to slowly or not at all allows the >>> coils to drop in temperature so that the buildup of condensation freezes. >>> >>> Debris. Any sort of debris in the evaporator unit can restrict air flow >>> to the coils, resulting in the same problem as occurs with a faulty fan. >>> >>> Low coolant level. If the level of freon is low, the coils will be at a >>> temperature much lower than is normal. The excess condensation builds up >>> and forms into ice. >>> >>> *I will suggest you to contact a technician , he can pinpoint the exact >>> reason.* >>> >>> Q7 Why is Japan one of the most developed countries yet it >>> does not have any minerals including oil? >>> >>> A7 Susanna Viljanen Works at Aalto University Updated Apr 4 >>> >>> You basically answered your own question. *When there are no natural >>> resources, the only resource are human resources. The same applies to >>> Scandinavia.* >>> >>> Abundant natural resources have never made one single nation rich and >>> prosperous - only its ruling class. This is known as the resource curse >>> >>> . Countries rich in natural resources tend to be rotten and corrupt. >>> *Conversely, >>> those which are poor in natural resources tend to be rich and wealthy >>> because all permanent wealth is created by human labour and knowhow*. >>> >>> Q8 What does a raw banana need to be yellow? >>> >>> A8 Ken SaladinTextbook author and professor emeritus Apr 23 >>> >>> When a fruit is immature, in many cases it’s green. Frugivorous >>> (fruit-eating) animals know that as a sign that it will not be very >>> appetizing, it may even be bitter or repugnant to eat, and it will not give >>> a good nutritional reward for eating it. *As their seeds mature, fruits >>> change to colors more attractive to frugivores—red, yellow, blue, etc.—*and >>> they load up with nutritional rewards, especially sugars that will be >>> agreeable to the tongue and energy-rich to the body. *The yellow color >>> comes from pigments common in vegetables, the carotenoids, which show >>> through as the fruit ripens and its green chlorophyll degrades enough for >>> the yellow to show through.* >>> >>> You could think of a banana’s yellow color as an “I’m ready and I’m >>> yummy” signal, an enticement to eat it. Yet in the case of bananas, you >>> must realize *that wild bananas are nothing like the highly selected, >>> cultivated, large yellow bananas we get from the grocery store now*. >>> Indeed these bananas are seedless and propagated only asexually, so there >>> is no seed-dispersal benefit for the banana to be eaten. So we might >>> just as well think of the carotenoid-rich yellow as a trait that >>> horticulturists have bred into bananas for marketing purposes—that >>> state between green and brown when the banana is tastiest. >>> >>> Here are some wild-type bananas—not exactly your grocer’s >>> plantation-grown Chiquitas. >>> >>> Q9 What difficulties does a person face if they have never >>> married in their entire life? >>> >>> A9 D D Rishi Former IRS | Advocate | LL. M.,Ph.D. (Law) | >>> Mar 24 >>> >>> I know a lot many people who did not get married. I think the major >>> problem they face is that when they are 60+ and not in good health, they >>> feel the need for a companion which they did not feel earlier. When you >>> are ill and lonely at home, life can be tough. I don't think there is any >>> major issue apart from loneliness, particularly at advanced age. >>> >>> *My note- I know of a person remained bachelor* and stayed in a lodge. >>> Once he got retired the lodge people desired he should vacate the room. He >>> did not bothered of his relatives while in service, but he was forced to >>> move to his home. >>> >>> Q10 Is Darwin the first person to find theory of evolution? >>> >>> A10 Claire Jordan Degree in biology and folklore; programmer, >>> shop owner, secretary on newspaper Sun >>> >>> *No. Evolution itself had been recognised for thousands of years*, and >>> as for the theory that it worked mainly by natural selection Darwin wasn’t >>> even the first. *19th C Briton to come up with it, but the third.* But >>> he wrote the first comprehensive book on it. >>> >>> *The first, at least in the 19th C, was Patrick Matthew,* *a Scottish >>> agriculturist* who wrote about natural selection in a book on >>> commercial forestry in 1831, but thought it so self-evident that he just >>> dashed off a few paragraphs on it in an appendix. >>> >>> *Then there was Alfred Russell Wallace, who* independently came up with >>> the idea of natural selection and researched it at the same time as Darwin, >>> and a paper of his on the subject was co-published with some of Darwin’s >>> writings in 1858, but then Darwin published a full book on it the following >>> year. >>> >>> *All the above QA are from Quora website on 28-04- 2022. * >>> >>> *Quora answers need not be 100% correct answers * >>> >>> *Compiled **and posted by R. Gopala krishnan on 29-04-2022* >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "iyer123" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/iyer123/538340659.1854802.1651188553807%40mail.yahoo.com >>> <https://groups.google.com/d/msgid/iyer123/538340659.1854802.1651188553807%40mail.yahoo.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "Thatha_Patty" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/thatha_patty/CAL5XZoqhUcLB5pRUdOxKYmKVkRe6CnuoB4nkkxZDJzrba7G4Ew%40mail.gmail.com >> <https://groups.google.com/d/msgid/thatha_patty/CAL5XZoqhUcLB5pRUdOxKYmKVkRe6CnuoB4nkkxZDJzrba7G4Ew%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > > > -- > *Mar* > -- You received this message because you are subscribed to the Google Groups "Thatha_Patty" group. 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