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Parenting & Child Development Objective: 3.01 Hereditary vs. Environment. I want you to stand up if you have…. Father’s eye color and shape Mother’s physical build Father’s feet (appearance) Mother’s hand size Father’s hair texture and color Mother’s skin color.
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Parenting & Child Development Objective: 3.01 Hereditary vs. Environment
I want you to stand up if you have…. • Father’s eye color and shape • Mother’s physical build • Father’s feet (appearance) • Mother’s hand size • Father’s hair texture and color • Mother’s skin color
What does all of this have to do with??? • If you stood up, you received all of those genetic, physical features from your parents or grandparents. • We look the way we do because of our inherited traits
Physical Traits are… • Characteristics connected with the body • Example: • Eye and hair color
Heredity skin color • Passing on of certain characteristics from earlier generations. Each person inherits many characteristics from their parents, which include, but not limited to: feet ears blood type color/shape of eyes hair texture color physical build size of hands
Heredity • Every baby receives 46 chromosomes • (tiny threadlike particles in the nucleus of every cell) • These chromosomes come in 23 pairs. • 2/46=23 2. The father’s sperm and mother’s ovum (egg) both contribute one chromosome to each pair.
Heredity • Each chromosome has thousands of genes. • Determine child’s inherited characteristics. • For every inherited characteristic, a person receives two copies of a gene • 1 from mother • 1 from the father • If Both are the same, the child has that characteristic. • Ex: 2 genes for blue eyes gives the child blue eyes.
Genes Recessive a. Recessive and Dominant Genes 1. Recessive is the weaker gene (-) 2. Dominant is the stronger gene (+) Scenario: • If a person receives two different genes, such as one for blue eyes and one gene for brown eyes, the dominant gene will express the characteristic over the weaker gene. • Brown eyes are dominant while blue eyes are recessive. • Therefore, the child will he born with brown eyes. Dominant
Recessive & Dominant Genes… Blonde hair What genes did the little girl receive from which parent? Mother Straight hair Mother Eye color ??both??
Female/Male Determination • OVUM=EGG • Female cell needed for reproduction • SPERM • Male sex cell needed for reproduction
How do you get a boy or girl? • Ovum sex chromosome carries “X” • X=GIRL • Sperm sex chromosome carries “X” OR “Y” • Y=BOY • Who determines sex of the baby? • Father=ALWAYS!!!
Scenario • IF a sperm fertilizes THE egg and it’s an “X” chromosome, what will your baby be? BOY OR GIRL?? • GIRL=“X” Chromosome! • IF the sperm fertilizes THE egg and it’s a “Y’’ chromosome? • BOY=“Y” Chromosome! • What chromosome did your father contribute? • XorY?
A Unique Person • Heredity explains why brothers and sisters often resemble each other and why they can also look different. • Each sperm cell contains a different combination of genes. • When they combine in a fertilized egg, they produce a unique individual. • The particular combinations of genes brought together at conception determine traits.
Identical (matching) Twins After fertilization of the ovum by the sperm, if the one egg splits into two separate eggs its identical twins. Have to be same sex, came from 1 sperm Two Fetus’ in the mother’s womb= amniotic “sac” & placenta
Fraternal (not matching) Twins • If two separate sperm fertilize two separate eggs, the result is fraternal twins, can be same or opposite sex
The CanadianDionne sisters, 1947. First (and only identical) quintuplets known to survive infancy. The chance of identical quintuplets being born is 1 in 57 million.
Environment . The environment does not influence a person’s physical (bodily) traits. People Places Things that surround and influence a person
Environmental Influences on Birth Defects • Not eating properly • Exposure • Diseases and/or infections • Chemicals • X rays • Accidental injuries • Toxoplasmosis – parasite in cat feces • Harmful substances • Drugs • Alcohol • Nicotine • Cigarettes
Hereditary or Environmental Influences? • Uniqueness of a child comes from his or her heredity and environment.
Answers • Mary has a great sense of humor. • E • Sue has blue eyes. • H • Billy and his brother Tommy look alike. • H • Sammy goes to the library often. • E • Karen plays the trumpet quite well. • E, H • Mary has brown hair. • H • Judy lives in a nice house. • E • Tom is tall like his father. • H • Dana always scores high on tests in school. • E, H • Chanda has dark skin. • H