Chapter 2: Factors of Human Development

                       "Factors of Human Development"

In the field of psychology, there have been many different areas of interest. One of the most popular areas of interest for those who study psychology is Human development. There are many great theorists that have different ideas concerning human development like Sigmund Freud, Erik Erikson and Piaget.

By the way what is human development? Human development or also known as Developmental Psychology is the process of growing to maturity. In biological terms, this entails growth from a one-celled zygote to an adult. It focuses on the chronological processes or changes which are cumulative. It encompasses the physical, cognitive, and socio-emotional changes that occur in an individual. The journey of human development is started from the infancy and keeps continue till the death.

The three (3) Main factors of human development are Genetics/Hereditary, Environment (nature) and Human reproduction.

Chromosomes are rod-shaped structures that contain all basic hereditary information of an organism. Every organism has twenty-three (23) pairs of chromosomes. The smaller units that are composed of sequences of DNA (deoxyribonucleic acid) are called Genes. XX combination results to a female child while XY combination results to a male child. The first stage of human development is fertilization follow by ovum, embryo, fetus, infancy, birth, babyhood, childhood, puberty, adolescence, adulthood, middle age, old age and lastly Death. For every stage of human development, there are changes happening like physical change, emotional change, social change and cognitive change. Physical change refers to the changes in appearance of a baby. It includes height, weight, size and etc. Emotional change shows that your child is forming an independent identity and learning to be an adult. Social change refers to an alteration in the social structure of a social group or society, a change in the nature. Cognitive change refers to changes in mental skills such as memory or reasoning. 

Determination of twin is classified into two: the Fraternal twin and Identical twin.

Fraternal twins are conceived when a mother releases two separate eggs cell and these are fertilized by two separate sperms to form two separate embryos and the make two separate babies. It means 50% of their genes are share up. It can be boy/boy, girl/girl, boy/girl sets. Meanwhile Identical twins are conceived when a mother releases one egg and fertilized by one sperm from the father, and the embryo splits and two fetuses grow. If the zygote splits very early, they may develop separate placentas and separate sacs. These are called Dichorionic. But when the zygote split extremely late, it resulting to conjoined twin called Siamese twins. It is very rare type of twin.

There are different genetic defects like klinefelter’s syndrome XXY, Down syndrome and phenylketonuria. 

Klinefelter's Syndrome

Klinefelter’s syndrome XXY is an abnormal condition in a male characterized by usually two X and one Y chromosomes. 

Down Syndrome

Down syndrome is caused when zygote receives extra chromosomes (47 chromosomes) at the conception. Lastly Phenylketonuria (PKU) refers to child who is not able to produce an enzyme that is required for normal development. Sickle cell anemia refers to the disease characterized by abnormally shaped red blood cells. It can cause to the children to have poor appetite, swollen stomachs, yellowish eyes and cognitive difficulties. Tay-Sachs disease refers to a disease wherein the body is not capable of breaking down fats.

In conclusion, human development is a very important part of psychology because human development helps not only psychologist rather those who want to study the development of human from the fertilization until the death.  For me, we should love our parents because they are the reason why we live in the world today.