Life span Development

Introduction: Your life story
Developmental psychologists study the many ways in which people change over the lifespan. Key themes in developmental psychology include understanding the stage of lifespan development, the nature of change, and the interaction between heredity and environment.
Genetic Contribute to your Life story
At conception the union of the sperm and egg result in the single –celled zygote .the zygote contains genetic instructions inherited from the biological parents, encoded in the chromosomes. Chromosomes are made of deoxyribonucleic acid (DNA) .each chromosomes has thousands of DNA segments called genes, which encode instructions for making a particular protein.
 An organism’s unique genotype is found in almost every body cell. Cells differ not because they result from different gens being activated or expressed. Mapping of the human genome resulted in the discovery that humans have only 20000-25000 genes. Gene variations are alleles. Some gene alleles are dominant or recessive. Most characteristics involve the interaction of multiple genes.
The phenotype results from the interaction of genes and environmental factors. Different genotypes respond differently to the same environmental factors.
Prenatal Development
During the nine months that make up the prenatal stage, the zygote develops into a full-term fetus. The embryonic period, and the fetal period, the greatest vulnerability to dermatogens occurs during the embryonic stage, when major bodily systems are forming.
Development during Infancy and Childhood
Newborns are equipped with reflexes and sensory capabilities that enhance their chances for survival. Vision, hearing, and smell are attuned to interaction with caregivers. The brain develops rapidly after birth the sequence of motor skill development is generally universal, although there is individual variation in the rate of development.
Thomas and chess demonstrated that infants seem to be born with different temperaments .they identified three basic temperamental patterns: easy, difficult and slow to warm up. According to Kalgan infants can be classified in terms of reactivity. Temperamental qualities seem to have biological basis and persist through life, although they can be modified by environmental influences.
According to attachments theory, the infant’s ability to thrive is dependent on the quality of his or her attachments to caregivers. Secure attachment develops when parents are sensitive and responsive to the infant’s needs. Insecure to the infant’s needs.
Infants are biologically predisposed to learn language. Adults encourage language development in infants by using motherese, also called infant-directed speech.
The stage of language development includes cooing, babbling, the one-word stage, and the two-word stage. At every stage, comprehensions vocabulary is larger than production vocabulary.
 Each culture attaches its own significance to gender. Gender roles and gender identity begin to develop in early childhood. During childhood, boys and girls develop different toy preferences and play with members of their sex.
Two contemporary theories that explain gender-role development are social learning theory and gender schema theory. Social learning theory is based on the principles of learning. Through reinforcement, punishment, and modeling, children learn the appropriate behaviors for each gender. Gender schema theory is based on the idea that children actively developmental categories for each gender. Children’s gender schemas influence what they learn and remember.
According to Jean Piaget’s theory of cognitive development, children progress through distinct cognitive stages, each of which represents a shift in how they think and understand the world.