Fertilization and Development DO NOW 13 In packet Question #1 only (few parts)

Covered So Far DNA & Genes Reproduction Asexual Mitosis Cancer ___________________________________ Sexual Sex Cells Haploid / Diploid Meiosis Crossing Over Variation Gametogenesis _____________________________________ Male organs Female organs Menstruation Main Ideas Fertilization Fallopian Tubes / Uterus / Placenta Fetal Development Identical & Fraternal Twins Fetal Risk Factors Reproduction Part IV

What if Fertilization DOES occur?

 If fertilization occurs then the process of will not happen!  An egg will become fertilized. A fertilized egg is known as a _________ Menstruation Zygote

Human Fertilization Fertilization – 1 sperm fuses with 1 egg creating a zygote  Haploid Sperm + Haploid Egg = Diploid Zygote 23

Fertilization the Story  Sperm are deposited in the vagina, travel past the cervix into the uterus then finally into BOTH fallopian tubes.  Fertilization occurs in the fallopian tube and creates variation!  Any 1 of the 200 – 400 million unique sperm can fuse with the egg!  The fertilized egg is called a zygote

Twins? Can more than one egg be fertilized?  Yes, if more than one egg is released Fraternal Twins Then how are identical twins produced?  When one zygote divides into two separate cells, (2 separate zygotes) during cleavage  2 separate eggs are fertilized by different sperm

After Fertilization What happens after the egg has been fertilized in the fallopian tube?  Fertilized egg (zygote) travels through the rest of the fallopian tube and begins to divide by Will every cell in the new baby have the EXACT same DNA? Why? MITOSIS

Meiosis -> Fertilization -> Mitosis As zygote travels in the oviduct, it begins a process called Cleavage Cleavage - process in the Oviduct where the zygote divides by mitosis increasing the amount of cells (forming 2 cells, 4 cells and so on) What do you notice about the size of the ball of cells as cleavage occurs?  The number of cells increase by the size of the diving zygote remains the same

Meiosis -> Fertilization -> Mitosis As cleavage occurs, a ball of about 50 cells forms the morula Cells will keep on dividing into a hollow ball called the blastocyst Zygote Morula Blastocyst

Fertilization – Cleavage - _____________ After the zygote undergoes cleavage and becomes a blastocyst, what happens next? Implantation Implantation & growth

DO NOW 13 Complete DO NOW 13 #2-7

Fertilization – Cleavage - Implantation After implantation of the blastocyst into the wall of the uterus, a process known as gastrulation occurs. Gastrulation:  Blastocyst bend inwards and is called a gastrula  The gastrula bends inwards and forms 3 different layers The three layers will differentiate into specialized tissues and organs

Cell Differentiation – When rapidly dividing cells take on specific functions. All cells have the same DNA but use different parts of DNA

Internal Development As the different body systems develop, the developing embryo needs nutrients! Yolk Sac – Provides nutrients for the early embryo before the umbilical cord and placenta form

Eventually the placenta and umbilical cord form

Placenta & Umbilical Cord Placenta  Responsible for nourishing the fetus and removing fetal waste  Filled with capillaries for _______________________ __________________________ diffuse into the embryo’s blood from the mother (for nourishment) ________________________________ diffuse into the mothers blood for removal Diffusion Nutrients and Oxygen Carbon Dioxide and other wastes

Placenta & Umbilical Cord The mother’s blood NEVER mixes with the blood of the fetus!!  Why ?

Placenta & Umbilical Cord Umbilical Cord  The placenta gets the nutrients  The nutrients travel through the umbilical cord to the fetus

DO NOW 74 pg.14 Complete DO NOW 74 #1, 2, 4, 5, 7, 8, 11, 12, 13

Complete DO NOW 74 #1, 2, 4, 5, 7, 8, 11, 12, 13

Complete DO NOW 74 #1, 2, 4, 5, 7, 8, 11, 12, 13

Placenta & Diffusion Whatever the mother takes in her body during pregnancy will diffuse into the growing fetus! What does this mean: Mother smokes  chemicals diffuse into fetus Mother does drugs  drugs diffuse into fetus Mother eats pizza  nutrients diffuse into fetus Mother breathes oxygen  oxygen diffuses into fetus Mother breathes carbon monoxide  CO diffuses into fetus Mother drinks alcohol  alcohol diffuse into fetus

Placenta & Diffusion If an adult smokes, it can cause cancer, poor circulation, and many other problems. What is damaged in cells from chemicals in cigarettes? Do you get as much oxygen per breath if you smoke? This would be horrific for a developing fetus because cells are differentiating, meaning cells are growing and dividing into the actual tissues and major organs of the baby!! If cell division is “messed up” organs will form incorrectly, not completely or not at all! Less oxygen = low birth weight! Alcohol = #1 agent that causes defects Alcohol shuts down adult livers! Imagine the damage it can cause in a fetus Causes Fetal Alcohol Syndrome (low birth weight, facial and physical abnormalities)

Do the data in the tables justify scientists' conclusions that alcohol causes physical abnormalities at birth by interfering with the normal development of the fetus? Defend your position with supporting data. DO NOW 74 In packet pg. 11 Question 19 & 20

Baby is Born Baby is born after 9 months in humans! The time the baby takes to develop is known as gestation.

If squeamish do not look A fter the baby is born, the placenta will come out the vagina a few minutes after the baby … here is what the placenta looks like after the baby is born

What side is the maternal side and what side is the fetal side?

DO NOW 74 pg.14 Complete DO NOW 74 #6, 9, 10,

DO NOW 74 pg.14 Complete DO NOW 74 #

DO NOW 74 pg.14 Complete DO NOW 74 #