IFD

1
Chapter 2

• IFD

2
OBJECTIVES

• Explain the process of heredity.
• Identify the characteristics that a person
  inherits.
• Explain the role of heredity as only one of many
  factors influencing life success.
• You have heritage that has been given to you by
  your ancestors. Because of your family you have
  unique characteristics. Some are visible, some
  are invisible, but all influence development.
  What inherited characteristics are you proud of?

3
The Process of Heredity

• Heredity information is contained in chromosomes
  humans have 23 pairs (46 total) in every cell of
  their body
• Dad gives 23 chromosomes thru sperm and mom gives
  23 chromosomes in egg
• Therefore child has 46 chromosomes in all
• Chromosomes reproduce themselves each cell in
  the body has 46 chrom. That are identical to the
  original 46

4
GENES

• A human chrom. Is composed of DNA
  (deoxyribonucleic acid)
• Each chrom. Can be viewed as a strand of 1000s of
  genes
• GENE basic unit of heredity
• Genes carry all characteristics that will be
  transferred
• Occur in pairs-1 from mom 1 from dad
• Many pairs work together to form each trait

5
DOMINANT/ RECESSIVE

• (Gregor Mendel founded laws of dom and rec genes
  in 1800s)
• Inherited traits are determined by genes. These
  genes are passed unchanged from generation to
  generation.
• Genes occur in pairs. A parent gives one of each
  pair of genes to an offspring.
• Where the 2 genes in a pair act differently, one
  gene often dominates the other. Thus, one gene
  is dominant (more influential or prevalent) and
  the other is recessive ( less influential or
  prevalent).
• The effect of a recessive gene may be masked by
  that of a dominant gene. However, if 2 recessive
  genes are paired the effect will be noticed.
• When traits are governed by different genes, the
  genes for each trait are transmitted
  independently. Thus the genes for 1 trait have
  no effect on the genes for other traits.

6
MUTATIONS

• The sperm and egg contain genes exactly like the
  genes the man and woman received from their
  parents.
• Rare exceptions when genes have Mutations
  chemical changes in genes
• Caused by either spontaneous error or thru some
  outside influence (like radiation)
• Ex. Atom bomb in Japan during WW2 caused severe
  damage-defective offspring

7
INHERITED CHARACTERISTICS

• heredity affects almost every aspect of your life
• Controls some traits completely (like gender and
  eye color)
• Heredity works with your environment in
  determining other traits like intelligence and
  longevity

8
Determination of Sex

• Most impt of all inherited characteristics is
  gender
• Of 23 pairs of chrom. 22 are alike in both males
  and females autosomes
• 23rd pair are the sex chromosomes
• Male x and y
• Female x and x
• If a sperm with an x chromosome combines with an
  egg, the fertilized egg will have 2 x chrom.
  (female)
• If a sperm with a Y combines with an egg (x) it
  will be xy (male)
• the men determine the sex of the baby b/c women
  all have xx

9
Sex-linked characteristics

• Characteristics that are determined by the genes
  on the x-chromosome
• Ex. Color blindness (cant distinguish between
  red and green-8 of males) and hemophilia
  (bleeding disorder in which blood clots very
  slowly)

10
FAMILY INTERACTIONS

• Your family provides you with daily experiences
  no other setting can give you. Each family
  member interacts with each other member. Every
  member of a family has a certain role.
• A Role is a socially expected behavior pattern.
• Your primary role now is Son or Daughter.
• You may also be a grandson or granddaughter.
• If you have siblings (brothers or sisters) you
  are also either a brother or sister.

11

• By now you have learned to get along with the
  other members of your family. Your reaction to
  each member is different. Sometimes siblings
  will compete for their parents love and
  attention. This is normal. It can help you
  develop a sense of sharing and compromise.

12
Sibling Rivalry

• a sense of competition with your brothers and
  sisters.
• Siblings also offer companionship. Loving family
  members provide a source of emotional support to
  one another all throughout life.

13
INFLUENCES OF BIRTH ORDER

• Personality traits and roles in the family
  dynamics are shaped by the age of the children in
  relation to one another.

14
OLDEST CHILD

• Center of parents attention until others arrived
• First to be treated as an adult and friend by
  parents
• More responsibility
• Most likely to go to college
• Strongest desire to achieve
• Seek a marriage partner who will let them take
  charge
• More independent in relationships
• Less outwardly affectionate

15
MIDDLE CHILD

• Companionship of a sibling, always
• Less responsibility and less independent
• May feel pressured
• May feel less interesting, not as cute
• Good all-around students
• May feel overshadowed
• Parents may be less demanding
• Good at dealing with the ups and downs
  in relationships
• Peacemakers
• Seek calm- even tempered marriage partners

16
YOUNGEST CHILD

• Given a lot of attention
• More family members bossing them around
• Expected to mature quickly and catch-up
• Pampered and indulged
• Seek a marriage partner who is warm
  and capable of taking charge