GENETICS AND BEHAVIOR HEREDITY AND ENVIRONMENT 1 st

GENETICS AND BEHAVIOR HEREDITY AND ENVIRONMENT 1 st year BSc Done by Jagruti

HEREDITY � Heredity is considered as ‘’the sum total of inborn individual traits’’. Biologically, it has been defined as ‘’the sum total of traits potentially present in the fertilized ovum’’. � According to Douglas and Holland ‘’one’s heredity consists of all the structures, physical characteristics, functions or capacities derived from parents other ancestry or species’’.

MECHANISM OF HEREDITY q q q The life cycle of an individual begins with the fusion of a sperm and ovum. GENETICS: The study of the way animals and plants pass on to their offspring such as: eye colour, hair colour, height, body build, blood types, intelligence, gender, etc. HEREDITY: Characteristics that a child receives from both the parents.

� CELL: Basic unit of all living matter (Adult= over 10 trillion cells). � CYTOPLASM: Substance of a cell outside of the nucleus. � NUCLEUS: Central point of cell/ contains genetic coding for maintaining life systems and issuing commands for growth and development. � CHROMOSOMES: 46 in each Nucleus (23 pairs) � GENES: Bands on chromosomes.

? ? ? How many chromosomes are there in each cell? � 46 CHROMOSOMES or 23 PAIRS How many chromosomes are in reproductive or germ cells? � 23 CHROMOSOMES (Combined = 46 chromosomes)

XX � Male Sex Cells XY � Female � Baby Sex Cells Girl = � Conception SPERM. � GENDER XX Baby Boy = XY is the union of an OVUM and is determined by the father!

� DOMINATE GENE: More powerful trait seen in a person. � RECESSIVE GENE: Weaker and hides in the background. Trait can only determine when two of them are present- may show up in future generations. � CARRIER: Has a recessive gene that is not visible. � SEX LINKED: Mother passes the recessive X to son.

MULTIPLE BIRTHS � ZYCOT: the cell that is formed when the sperm fertilized the egg. � MONOGYGOT: Identical twins 1 egg + 1 sperm � DIZYGOT: Fraternal twins 2 eggs + different sperm � MULTIPLE BIRTHS: More than 2 � CONJOINED: Ovum splits apart, but the separation is not completed. Babies are joined at some part of the body.

FACTORS THAT CONTRIBUTE TO MULTIPLE BIRTHS � History in the family � Increased hormones naturally (More than one egg released) � Fertility Drugs � Age 32 -36

� Occasionally, through some unfortunate bodily error, aberrations in chromosomes appears. If an extra chromosome appears making the total 47 rather than the normal 46, mongolism (Down syndrome) results. � A child with mongolism suffers from deceleration of growth during prenatal period, which results in a highly complex, multidimensional disorder, in which every organ is involved.

ENVIRONMENT � The environment is everything that affects the individual except his genes. (Boring, Lang field and Weld) � Environment covers all the outside factors that have acted on the individual, since he began life. (Woodworth)

TYPES OF ENVIRONMENT are three types of environment that affect the individual directly or indirectly. � INTERCELLULAR ENVIRONMENT � INTRAUTERINE ENVIRONMENT � EXTERNAL ENVIRONMENT a) Physical environment b) Biological environment c) Psychosocial environment � There