This document discusses human development from conception through old age. It describes key stages of development such as prenatal, infancy, toddlerhood, childhood, puberty, adolescence, and adulthood. For each life stage, it outlines important physical, cognitive, emotional, and social milestones. The document also explains that development is a continuous process that depends on both maturation and environmental factors.

1. Beltran (1998) further explains that environment refers to any
factor, which an individual comes in contact with, after then, hereditary
pattern has been received through the germ plasm. This includes
training, learning, influence of home, neighborhood, hospital, church,
play yard, climate, geographical location, and all others that stimulate
the senses in any way.
The effect or influence of heredity and environment differs from
one individual to the other and from each trait to another trait.
Heredity and environment are independent forces. In some
cases, the effect of heredity is stronger or predominant. In other cases,
the effect of environment is more dominant.
heredity lays down the necessary foundations while
environment changes or modifies these foundations for good or bad.

2. Behavioral attitude such as intelligence,
temperament, and sociability are strongly
influenced by environmental factors. Even physical
characteristics such as height and weight depend
to some extent on one’s medical history and the
adequacy of diet. In summary, many human
attributes are the product a long and involved
interplay between the forces of nature and nurture.

3. The psychologist is primarily concerned with two
environmental influences: the internal environment, those
stimuli acting within the individual, and the external
environment, those stimuli impinging upon the organism.
Internal Environment
1. Intracellular System – consist of physical and
chemical forces within the cell that influence the genetic
material of the nucleus.
2. Intercellular System – consist of the fluids that
surround the cells and influence their growth and
development.

4. External Environment
1. Pre-natal environment – consist of the amniotic fluid
that sounds the fetus, the stimulation provided by its
positioning within the mother, and the materials
provided and taken away by the mother’s body.
2. Post-natal environment – consist of the infinitively
complex arrays of stimulation that confront the child
after birth.
3. Psychological environment – consist of those
aspects of the organism’s physical surroundings
capable of influencing its structure or its behavior.

5. A hereditary basis for sex differences becomes clear if we
examine the chromosomes of normal men and women. It is apparent
that 22 of 23 pairs of chromosomes found in human beings are the
same in males and females. The 23rd pair consist of an X and Y –
chromosomes. In the female, it contains both X chromosomes.
Therefore, the presence o a y means a genetic female. If a sperm
carrying a y chromosome fertilizes the egg or ovum, the product is an
XY zygote or male. If a sperm carrying an X chromosome reaches the
ovum first, the result is an XX zygote or female.

6. About 1 of every 270 zygotes divides in two and develops as two
separate individuals or identical twins. These individuals are called
monozygotic twins since they come from a single zygote. They have exactly
the same hereditary pattern. They look alike and have the same sex. Most
twins are not identical but fraternal or dizygotic. They result when the mother
releases two ova at almost the same time and different sperms fertilize each
ovum. Dizygotic twins come from separate zygotes that have separate
hereditary patterns. They may differ in appearance and maybe of the same
or different sexes.
When the division of the zygote is not complete, the product is a
pair of Siamese twins who maybe joined at the buttocks, chest, neck, or
other part of the body. This seldom happens.
There are also cases when triplets, quadruplets, and other multiple
births are produced especially now that fertility pills have been introduced.

7. Hurclock (in Aquino and Miranda, 1991) defines development
as a progressive process of changes that occur in an orderly,
predictable pattern as a result of maturation and experience. Beltran
(1998) explains that the primary interests are the changes that occur in
physical growth and motor skills, mental or reasoning abilities,
emotional expression, and pattern of social behavior. Human
development is best described as a continual and cumulative process.
The only thing that is constant is change, and the changes that occur
at each major phase of life have important implications for the future

8. Proud of Life Chronological Time Frame
1. Pre-natal
2. Infancy
3. Toddler early childhood
4. Pre-school
5. Late childhood
6. Puberty
7. Adolescence
8. Young adulthood
9. Middle age
10.Old age or senescence
Conception to birth
First two years of life
2 to 3 years of age
4-6 years of age
End of 6 to 13 or 14 years age
(onset of puberty marks the end
of this period)
End of childhood to early part of
adolescence
End of 13 or 14 to 20 years of
age
End of 20 to 40 years of age
End of 40 to 65 years of age
End of 65 years and older

9. Life begins at the time of conception when a sperm fertilizes the
ovum. The union of the ovum and sperm produces a fertilized egg
known as zygote. The pre-natal period is approximately 9 months or
270 days. It is divided into the following:
1. Period of the zygote – This is from fertilization of the second
week.
2. Period of the embryo – This is from the end of the second week
to the eight week.
3. Period of the fetus – This is from the end of the eight week to
birth.

10. After birth, life becomes very much in contrast with pre-natal life. The infant
who used to be completely dependent upon the mother for continuous
nourishment, breathing, urination, defecation, and other processes is now
starting to struggle and meet the demand to live normally. The birth cry is
actually a reflex behavior to establish breathing. Other automatic or reflex
responses though unlearned can be performed through stimulation.
Among these are grasping reflex, pupillary reflex, plantar reflex, and knee-
jerk or patellar reflex. Grasping reflex is exhibited when you place your
finger in an infant’s palm and he grasps it tightly. The pupillary reflex
causes the pupil of the infant’s eye to contract if a ray of light is shone into
his eye.

11. The term toddler adequately describes most two-year olds
who often fall down when they try to go somewhere in a hurry. As
the toddler matures, his locomotor skills improve. By age 3, he can
walk or run in a straight line and leap off the floor with both feet.
Three-year-old toddlers find it difficult to button their clothing, tie a
shoe or copy a figure on a piece of paper.
Three to six years oild is known as pre-schooler. He
becomes very naughty and curious about almost anything. By age
five, he starts to be graceful and his large muscle activities because
he is losing much of his baby fats as he grows in height. His eye-
hand and small muscle coordination also improves.

12. About the time child enters the first grade, he can copy
complex figures, cut out angular patterns with a pair of scissors, and
print neatly and accurately. His improved small muscle coordination
enables him to take up and enjoy hobbies such as assembling
models, painting their numbers, and sewing. By eight to nine he can
use screwdrivers and can openers and had become a skillful
performer at games such as baseball and soccer that require eye-
hand coordination.

13. The term puberty refers to that point in life when the
individual reaches sexual maturity and becomes capable of
producing a child. It is generally assumed that a girl becomes
sexually mature at menarche, the time of her menstrual period.
The timing of puberty in males is much harder to pin point since
production of sperm is not a readily observable phenomenon.
The most common sign of masculine puberty is the appearance
of pigmented pubic hair.

14. Growth spurt, which is the rapid acceleration in height
and weight, signals the beginning of adolescence period. In
addition to growing taller and heavier, the body assumes an
adult-like appearance during the adolescent growth spurt. The
most noticeable changes are widening of the hips for females
and broadening of the of the shoulders for males. Maturation of
the reproductive system occurs at roughly the same time as the
adolescence growth spurt and follows a predictable sequence for
each sex.

15. As a girl enters her height spurt, the breast grow
rapidly, pubic hair appear, and the sex organ begins to
mature. For boys, the onset for sexual maturation begins
with the initial enlargement of the testes and scrotum. The
growth of the testes is accompanied or soon followed by the
appearance of unpigmented pubic hair. After reaching
sexual maturity the boy’s voice will begin to change from the
soprano of childhood to the baritone of adulthood.

16. The problems of adolescent concern his social, emotional,
moral, and economic maturity. An Adolescent works
towards the achievement of the criteria of adulthood,
which are independence of family, emotional maturity,
social maturity, economic independence, intellectual
adulthood, use of Leisure, philosophy of life, and achieving
heterosexuality.

17. A young adult, according to Erikson, must work towards settling down
to a full life of work. He should acquire social consciousness to be
productive not only for himself but for others. He must be ready and
willing to accept responsibilities as a parent. He must achieve the
criteria of adulthood.
Middle or Late Adulthood (end of 40 to 65 years old)
During the period, physical and mental powers deteriorate.
Man reaches his climacteric period and woman for menopausal period.
The reproductive organs then slowly lose their functionability. Motor
and cognitive ability decreases with age. Middle age people divert
their activities from those that need much physical exertion to the less
or non-strenuous ones.

18. Old Age or Senescence (end of 65 years and older)
Old people become more eccentric and egocentric due to
mental disorganization and physical breakdown. The become
careless, absent-minded, socially withdrawn, and poorly adjusted.
They feel useless and worthless, sensitive, and emotional. They
developed unfavorable self-concepts (Beltran, 1998).

19. 1. Development is a continuous process from conception to maturity.
2. Development depends upon the maturation and growth of fatty
casings around certain nerves of the nervous system.
3. The sequence of development is the same for all children.
Although the sequence may be programmed, the actual time at
which a child reaches a particular step and his level of prior skills
will vary with nutritional adequacy and environmental
encouragement.

20. 4. Certain reflexes present at birth anticipate voluntary movement.
For example, the sucking reflex gives way directly to movements
toward the breast by infants.
5. The direction of development is cephalocaudal; that is,
coordination and control begin in the head region followed by the
spinal muscles in the head region and finally the spinal muscles
and legs develop coordination.
6. Generalized activity gives way to specific responses