When you finish this article, you’ll be older than when you started it! That’s because growing older is a gradual, life-long process.
Aging starts at the moment you are born. How old is old? You may think you’re young, but someone your age is old to a baby brother or sister. The longest human life span — the length of time between birth and death — isn’t more than 120 years, and hasn’t changed much over the course of history. But life expectancy — the average length of time a person of a particular age may expect to live — has changed dramatically. If you were born in 1900 in this country, you could have expected to live 47 years.
A baby born today can expect to live almost 76 years. Better nutrition and clean drinking water as well as biomedical discoveries such as the immunizations you get to prevent measles and other diseases and medicines that treat strep throat have all brought about this change. We all age differently. Some people get deep wrinkles, others don’t. You can get clues about how you will age by studying your parents and grandparents.
Scientists believe that heredity, or the passing of traits from parents to their children, is responsible for about 30% of the differences in life expectancy. Genetics Essay Next time you’re at a family gathering, notice if there are any striking patterns. Do you have many tall relatives? What color is their hair? The way you look is determined by genes, which hold the instructions our bodies use to make our features. For every feature (such as eye color, dimples or face shape), a baby inherits two sets of genes, one from its mother and one from its father.
Which genes the baby gets from each parent is random, like flipping a coin. There are thousands of genes, thousands of features, and millions of possible combinations — which is why you may have different hair color than your brother or sister. Genes also hold information that causes diseases. These diseases are called genetic, or inherited, diseases. Cystic fibrosis is an example of a genetic disease. Some genetic diseases don’t show up until later in life, even though the genes are present from birth.
Genes may play a part in the changes in your body when you become a teenager, as well as the normal changes that happen as people grow older. As people get older, they may have trouble with eyesight and hearing and their senses of taste and smell may not be as sharp. Appearance changes too; hair turns gray, and skin gets wrinkled. Older people may slow down physically, and their memories may not be quite as sharp. But people over the age of 70 still have hobbies and interests, play sports, make jokes.
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