Heredity and Environment

most of us enjoy the sight of beautiful riding horses the smooth lines The Grace Of Motion the flowing muscles consider then this poor relative he's just as much a horse as the others but what a contrast what makes horses resemble each other in some ways yet differ so widely in [Music] others what for that matter makes people so much alike and yet so different from each other what makes you what you are behind you behind each of us there are influences of two general sorts from your parents and grandparents and from all the rest of your ancestors you receive certain influences you're born with them we call these influences your heredity after your birth the people around you exert influences on you so does the society in which you live so does is the world of nature itself we call these influences your environment together heredity and environment make you the person you are heredity and environment make Hank Johnson the person he is the writing stable where he works part-time is part of his environment so is a Johnson Farm where Hank lives Hank is proud of this herd of dairy cattle and he has every right to be proud for these are fine cattle they produce Rich milk in good [Music] quantity why is bossy such a good milk [Music] producer well first because she has good heredity she comes from a long line of good milk producers here are her sisters and cousins her mother and grandmother they too give plenty of good milk her father is this breeding bull the Johnson's keep his heredity too is favorable for high milk production but does heredity alone give bossy all she needs to produce good milk in quantity no indeed environment must play its part boss's environment includes the is clean Barn free from the annoyance of flies it includes good feed and gentle care and regular feeding and milking habits boss's environment all the influences from the world around her enables her to fulfill the high promise of her heredity a fine animal or person is the result of good influences from both heredity and environment now what are the principles by which heredity and environment function let's examine first the large principles of heredity one Offspring tend to resemble their parents this is true of dairy cattle and of pigs and of dogs and of course of people Offspring tend to resemble their parents but there are exceptions although Hank grew up and works in the same environment as his father still Hank has Fair hair and blue eyes his father and his mother have darker coloring in appearance then Hank does not resemble his parents although people who know him say that in many ways Hank is like his father so while it doesn't always hold true one principle of heredity is that Offspring tend to resemble their parents another is that Offspring vary according to known patterns of variation how many different possib abilities there are in a litter of kittens they vary from each other though in many ways they all resemble their parents how widely two brothers May differ from each other Offspring vary in appearance and in temperament again there are exceptions identical twins resemble each other far more than they do either parent but even the exceptions follow certain patterns of variation finally Offspring T toward the average year upon year of patient and careful breeding has given us many exotic varieties of pigeons but let that control breeding stop let Powter breed at will with fantail or with Tumblr and within a few Generations what have you just plain pigeons Offspring tend toward the average often this happens with people too a tall man and his quite short wife may have a daughter of about average height these then are the broader principles of heredity Offspring tend to resemble their parents Offspring vary from from each other Offspring tend toward the average in Long experiments scientists have charted patterns of hereditary influences through many generations of animals and plants their findings make up the study of genetics the study of how heredity works but now how does environment operates this sickly corn Grew From The Very finest hybrid seed it has very good heredity but what an environment poor soil choked with weeds not enough water no treatment for disease the result scraggly ears small yield this corn was grown from the same seed but with far better en environment plenty of water and Sun rich soil the right kinds of fertilizer plants and animals cannot control their environment but as for people well people too are shaped by environment but they can also influence their environment Hanks environment has had much to do with shaping him he's always lived on a farm think how different his life might have been if he'd been born in the city or grown up along the Sea Coast what if Hank's mother had been a musician and taught him to play or even suppose Hank had been brought up on a different Farm suppose his family had been less industrious all sorts of things might have happened to Hank because of differences in his environment with the very same heredity a different environment would have made him quite a different person but beyond this Hank himself plays a part in shaping his environment as do all of us you change your environment every time you work to improve your surroundings every time you choose a new friend every time you make plans for the future and carry them out every time you study to learn more of the world about you how well and how wisely you work to improve your environment determines how much you can improve yourself our heredity is determined we cannot change it but we can influence our environment this is the great possibility which lies in all of us to change our environment and make it better as Hank and his family have done to fulfill the best promise of our heredity we must work constantly to improve our environment and so live a happier Fuller [Music] [Applause] [Music] life