Presentation on theme: "What are multiple births?. w GENETICS - The study of the way animals & plants pass on to their offspring such as: w eye color, hair color, height, body."— Presentation transcript:
w GENETICS - The study of the way animals & plants pass on to their offspring such as: w eye color, hair color, height, body build, blood types, intelligence, gender, etc. w HEREDITY - Characteristics that a child receives from both parents
???????????????? w How many chromosomes are there in each cell? w 46 CHROMOSOMES or 23 PAIRS w How many chromosomes are in Reproductive (egg & sperm) or Germ cells? w 23 CHROMOSOMES (combined = the 46 chromosomes)
CELL DIVISION w MEIOSIS: Creates 1/2 sets of chromosomes Women = 23Men = 23 Combined = 46
w Female Sex CellsXX (Ovum or Egg) w Male Sex CellsXY (Sperm) w Baby Girl = XX Baby Boy = XY Conception is the union of an OVUM and the SPERM w Gender is determined by the father! Someone should have told King Henry VIII!
w DOMINATE Gene: More powerful or strongest gene- trait seen in person w RECESSIVE Gene: Weaker and hides in the background. Trait can only determine when two of them are present - may show up in future generations. w CARRIER: Has a recessive gene that is not visible w SEX-LINKED : Mother passes the recessive X to son Color-blind male receives the trait from his mother. The mother is usually not color-blind herself. w B = BROWN eyes (dominate)b = BLUE eyes (recessive) w BB = BROWN eyes w bb = BLUE eyes w Bb = BROWN eyes but carry the recessive BLUE eye gene
MULTIPLE BIRTHS w Identical Twins – when a fertilized egg splits into two Fertilized ovum splits into 2 identical cells - Always the same gender w Fraternal Twins - when 2 eggs are released and fertilized at the same time Will look different - May be different or the same gender
What 4 FACTORS may contribute to Multiple Births? w 1) History in the family w 2) Increased hormones naturally –More than 1 egg released w 3) Fertility Drugs –More than 1 egg released w 4) Age 32-36
March 20: Agenda w Goal: Understand environmental and hereditary influences on prenatal development and long- term effects on health of children. w Journal 11: In your own words; what is a birth defect, what are twins and the two types of twins we discussed ( how does this happen) what are the 4 factors that contribute to a birth defect?
Environmental Influences on Birth Defects w Inadequate nutrition of mother w Exposure to diseases or infections during pregnancy w Harmful substances consumed during pregnancy
Environmental Influences on Birth Defects Inadequate nutrition of mother Stunted brain development of baby Leads to mental retardation
Environmental Influences on Birth Defects Exposure to diseases or infections during pregnancy w Rubella, or German Measles, can cause blindness, deafness, heart disease, and mental retardation w Toxoplasmosis, can cause hearing loss, learning disabilities and death; found in cat litter and some raw meats w Chicken pox, scarring of babies’ skin, limb defects, eye problems, and miscarriage w STDs can be passed to unborn child and lead to serious illness, physical disabilities, or death
Environmental Influences on Birth Defects Harmful substances consumed during pregnancy w Nicotine from smoking tobacco or secondhand smoke Smaller babies Miscarriages and premature births Respiratory infections or allergies
Environmental Influences on Birth Defects Harmful substances consumed during pregnancy w Alcohol can cause fetal alcohol syndrome (FAS) 20% of infants die Facial deformities, delayed physical growth, heart defects, and hyperactivity Mental retardation or disabilities Poor coordination Difficulty controlling behavior
Environment Influences of Birth Defects Harmful substances consumed while pregnant w Drugs Over-the-the counter drugs Drug addiction Long-term learning and behavioral problems Risk of miscarriages Congenital heart problems
Environmental Influences on Birth Defects Exposure to hazards during pregnancy w Chemicals w X-rays w Toxoplasmosis – extreme high blood pressure
Environmental Influences on Birth Defects Accidental injuries w Cerebral palsy caused by damage to brain before, during, or shortly after birth w Falls lead to a variety of complications
Hereditary Influences on Birth Defects Dominant genes? Recessive genes? Can you explain the difference?
Hereditary Influences on Birth Defects 1. Defective recessive genes inherited from both parents Cystic fibrosis Tay-Sachs disease Sickle cell anemia 2. Defective dominant gene inherited from one parent Hemophilia Huntington’s disease Duchenne muscular dystrophy Color blindness 3. Errors in chromosomes Down syndrome
Tay-Sachs w Tay-Sachs disease is an untreatable disorder that is always fatal. Children born with Tay-Sachs appear normal at birth but lack an enzyme needed to break down certain fats. The fats build up and destroy brain and nerve cells, leading to rapid mental and physical deterioration and death in early childhood.
Combined Influence of Heredity and Environment Birth Defects w Drugs + virus = heart defect w Cleft lip/cleft palate w Spina Bifida – reduce risk by taking folic acid
Individual Activity In the blanks place an H if the factor is influenced by heredity, an E if the factor is environment, and B if it is both.
Case Study : Partner Activity Read case study and list the various influences in the correctly column
Scrapbook Page # 7 Family Tree w Create your family tree. w Begin with your grandparents and add on all your family members, include eye color and hair color. w BE NEAT!
Scrapbook Page 8 TWINS w Your twins: w Will they boys, girls, both w Will they be Identical or Fraternal and why? w Tell me what you will have to do to prepare for them….childcare choice etc… w Draw them!!