Download Eye and hair color

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
1.Passing on of certain
characteristics from earlier
feet
generations.
ears
Each person inherits many
characteristics from their parents,
which include, but not limited to:
color/shape
of eyes
hair texture
color
size of hands
blood type
physical build
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
a. Recessive and Dominant Genes Recessive
1. Recessive is the weaker gene (-)
2. Dominant is the stronger gene (+)
Dominant
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
CHARACTERISTICS
DOMINANT TRAITS
RECESSIVE TRAITS
eye coloring
brown eyes
grey, green, hazel, blue eyes
vision
farsightedness
normal vision
normal vision
normal vision
dark hair
non-red hair
curly hair
full head of hair
widow's peak
dimples
unattached earlobes
freckles
broad lips
immunity to poison ivy
normal pigmented skin
normal blood clotting
normal hearing
normal hearing and speaking
normal- no PKU
normal vision
nearsightedness
night blindness
color blindness*
blonde, light, red hair
red hair
straight hair
baldness*
normal hairline
no dimples
attached earlobes
no freckles
thin lips
susceptibility to poison ivy
albinism
hemophilia*
congenital deafness
deaf mutism
phenylketonuria (PKU)
hair
facial features
other
Recessive & Dominant
Genes…
Blonde hair
What
genes
did the
little girl
receive
from
which
parent?
Mother
Straight hair
Mother
Eye color
??both??
Male & Female Symbol
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?
• Sperm sex
• Ovum sex
chromosome
chromosome
carries “X” OR “Y”
carries “X”
– Y=BOY
• X=GIRL
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?
–
X or Y?
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.
!!TWINS!!
Here’s how it
works
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 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.
Environment
People
Places
Things
that surround and influence a person
The environment does not
influence a person’s physical
(bodily) traits.
.
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.
1.
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
Answers