Parenting & Parenting &

Child DevelopmentChild Development

Objective: 3.01 Objective: 3.01

Hereditary vs. Hereditary vs. EnvironmentEnvironment

I want you to stand up if you I want you to stand up if you have….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 What does all of this have to do with???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

• Let’s learn more!!!!!

Physical Traits are…Physical Traits are…

•Characteristics connected with the body

•Example: –Eye and hair color

HeredityHeredity1. Passing on of certain characteristics from earlier

generations.

1. Each person inherits many characteristics from their parents, which include, but not limited to:

physical buildskin color

hair texture/color color/shape of eyes

size of hands

feetears

blood type

HeredityHeredity• 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.

HeredityHeredity• 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

• Both are the same, the child has that characteristic.– Ex: 2 genes for green eyes

gives the child green eyes.

GenesGenes

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.

RecessiveDominant

DOMINANT & RECESSIVE CHARACTERISTICS

  DOMINANT TRAITS RECESSIVE TRAITS

eye coloring brown eyesgrey, green, hazel, blue eyes

vision farsightednessnormal visionnormal visionnormal vision

normal visionnearsightednessnight blindnesscolor blindness*

hair dark hairnon-red haircurly hairfull head of hairwidow's peak

blonde, light, red hairred hairstraight hairbaldness*normal hairline

facial features dimplesunattached earlobesfrecklesbroad lips

no dimplesattached earlobesno frecklesthin lips

other immunity to poison ivynormal pigmented skinnormal blood clottingnormal hearingnormal hearing and speakingnormal- no PKU

susceptibility to poison ivyalbinismhemophilia*congenital deafnessdeaf mutismphenylketonuria (PKU)

  

Recessive & Dominant Recessive & Dominant Genes…Genes…

What genes did the

little girl receive

from which

parent?

Blonde hair

Mother

Eye color

??both??

Straight hair

Mother

Male & Female SymbolMale & Female Symbol

Female/Male DeterminationFemale/Male Determination

• OVUM=EGG– Female cell needed for

reproduction

• SPERM– Male sex cell needed for

reproduction

How do you get a boy or girl?How do you get a boy or girl?

• Ovum sex chromosome carries “X” • X=GIRLX=GIRL

• Sperm sex chromosome carries “X” OR “Y”

– Y=BOYY=BOY

Who determines Who determines sexsex of the baby? of the baby?Father=ALWAYS!!!

ScenarioScenario• 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 What chromosome did your father contribute?contribute?

– XX or YY?

A Unique PersonA 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.

!!TWINS!! !!TWINS!! Here’s how it Here’s how it

worksworks

Identical Identical (matching) (matching) TwinsTwinsAfter fertilization of the ovum by the sperm, if the oneegg splits into two separate eggs its identical twins.

Two Fetus’ in the mother’s womb= amniotic “sac” & placenta

Have to be same

sex, came

from 1 sperm

Fraternal Fraternal (not matching) (not matching) TwinsTwins

• If two separate sperm fertilize two separate eggs, the result is fraternal twins, which can be same or opposite sex based on chromosomes.

The Canadian Dionne sisters, 1947. First (and only identical) quintuplets known to survive infancy. The chance of identical quintuplets being born is 1 in 57 million.

EnvironmentEnvironment

. The environment does not influence a person’s physical

(bodily) traits.

People Places Things

that surround and influence a person

Environmental Influences on Environmental Influences on Birth DefectsBirth Defects

• Not eating properly• Exposure

– Diseases and/or infections – Chemicals– X rays – Accidental injuries– Toxoplasmosis-extreme high blood pressure

• Harmful substances– Drugs– Alcohol– Nicotine

– Cigarettes

Human Traits InventoryHuman Traits Inventory

Hereditary or Environmental Hereditary or Environmental Influences?Influences?

• Directions: – Uniqueness of a child comes from his or

her heredity and environment. – Look at the list below and distinguish

between influences that can be linked to heredity and those that can be linked to environment.

– If the influence is due to heredity, write an H in the blank.

– If the influence is due to environment, write an E in the blank.

AnswersAnswers1. Mary has a great sense of humor.1. E

2. Sue has blue eyes.1. H

3. Billy and his brother Tommy look alike.1. H

4. Sammy goes to the library often.1. E

5. Karen plays the trumpet quite well.1. E, H

6. Mary has brown hair.1. H

7. Judy lives in a nice house.1. E

8. Tom is tall like his father.1. H

9. Dana always scores high on tests in school.1. E, H

10. Chanda has dark skin.1. H