Fertilization and Development in Humans Fertilization Fertilization the

Fertilization and Development in Humans

Fertilization • • Fertilization the _______ Fusion (joining) of the sperm and egg _______ nuclei Oviducts or fallopian tubes _______ in the ______________ Fertilization and _______ development is In humans, _______ Internal female _______ in the body of the _______. At the moment of fertilization, the egg develops a Protective membrane ______________ around itself to prevent other sperm _______ from penetrating. zygote A fertilized egg is called a _______ Name: egg _______ + sperm _______ = zygote _______ 23 23 46 Chromosome ______________ Number FERTILIZATION RESTORES THE SPECIES NUMBER OF CHROMOSOMES

As the Egg Travels Fraternal Twins 2 • Fertilization of _____ 2 sperm eggs by ___ • Female releases more than one _____ egg during ovulation Identical Twins • Fertilized zygote splits into 2 _____ identical embryos One egg was • Only _____ fertilized by One sperm ________

Advantages / Disadvantages of Internal Fertilization Advantages 1. Avoid hazards of the environment ________ 2. Eggs are well protected ________ Disadvantages 1. Sperm can only fertilize an egg for a short ________ period of time 2. Sperm live a short ________ time because they store little ________ food.

Animal Development (A) (B) 2 cell embryo egg zygote 4) _____ sperm 1) _____ 2) _____ 3) _____ Mesoderm 11)_____ (C) endoderm ectoderm 10)_____ 9) _____ 4 cell embryo 5) _____ blastula gastrula 8) _____ 7) _____ 6) 8_____ Fertilization A. ___________________ Cleavage by mitosis B. ___________________ Gastrulation and differentiation C. ___________________

Cleavage cleavage - after fertilization, the _____ zygote divides by • _____ two cells mitosisto produce __________ growth • Cell division continues without _____ embryo • Once cleavage begins, the zygote is called an _____ blastula - hollow ball formed by the embryo • _____ • implantation _____ - when the embryo attaches to the Uterine lining __________

Gastrulation • • • different from one another differentiation - embryo cells become _______________ • • job or function PROTEINS A CELL MAKES, DETERMINE ITS ________ THE _______ tissues and _____ organs of the new organism They form _____ GENES TURN ON OR OFF IN CERTAIN CELLS TO DIFFERENT _____ PRODUCE DIFFERENT PROTEINS _____ Three embryonic germ layers of the embryo • • • ectoderm - develops into _____ skin Nervous system _____ and __________ endoderm - develops into _____ digestive andrespiratory __________ systems mesoderm all _____ - develops into _____ other systems like the reproductive _____ and circulatory _____ systems ectoderm mesoderm endoderm

Growth in the Uterus • surrounds the embryo amnion - __________ protects the embryo, holds in a and_____ Amniotic fluid called __________ • placenta - organ responsible for the _____ diffusion of passage by __________, oxygen from the nutrients and __________ blood to the fetus. mother’s _____ wastes from the fetus _____ diffuse to _____ the mother’s blood through the placenta The mother’s and fetus’ _____. Never mix blood __________ Umbilical chord __________ - attaches the embryo to the _____. placenta Contains _____ Blood vessels __________ that connect the circulatory system to the embryo’s _____ capillaries of the placenta _____ •

Reproductive Technology Reproductive technology has greatly changed the way we can deal with reproduction of humans as well as other plants problems involving ________ and organisms. • Agriculture scientists have produced plants resistant to _____, insects Weed killers or even _______________, frost • • cloned to produce more resistant crops Resistant plants can be _____ • • Hormone therapy - enables infertile women to become pregnant __________ • Fertilized eggs are implanted into the woman’s uterus, The __________ and a ________pregnancy may result. successful • Miniature cameras allow doctors to view ultrasound and __________ ovaries _____, oviducts and other reproductive structures _____, Artificial insemination - used to reproduce farm animals that _____________ exhibit genetic advantages Invitro fertilization - eggs are extracted from an infertile woman __________ and _____ fertilized with sperm in a laboratory dish.

Invitro Fertilization

Amniocentesis amniocentesis - procedure to extract fluid from • ________ around the developing fetus amniotic fluid • Doctors analyze the cells in the _____ Chromosomal abnormalities and • _____________ Biochemical deficiencies can be detected that may __________ threaten the health of the developing fetus

• • Dangers that face a Fetus placenta prevents most infections that make the The _____ mother ill from passing to the fetus radiation - passes through the tissues of the mother and _____ may affect the fetus X-rays - damages the dividing _____ cells _____ of the fetus Infectious microorganisms - found within the mother can _____________ enter the fetus Cigarette smoking by the mother affects development in __________ the fetus and may produce underweight babies chemicals are also harmful to the toxins or _____ Exposure to _____ fetus alcohol during heroine _____, cocaine LSD, and _____ Use of _____, pregnancy can cause serious results intellectual deficienciescan result addiction __________ and __________ drugs and _____ alcohol passing from the mother’s from _____ blood to the fetus

Fertilization & Development in Other Organisms Fish and Amphibians • Fertilization is _____ external large • Females lay _____ numbers of eggs in the water • This ensures the _____ survival of the species deposit sperm over the eggs in the water • Males will _____ to fertilize them Advantages Disadvantages 1. Moist surroundings 1. Egg and sperm may not _____ meet 2. Eggs may be _____ eaten 3. Changes in environment may _________ destroy the eggs and sperm water (_____, temperature and ________, Oxygen concentration _____________

Fertilization & Development in Other Organisms Birds and Reptiles internal within the • In birds and reptiles, fertilization is _____, female’s reproductive tract reptiles produce a _____ leathery shell around the egg • _____ development is external – outside the female’s body and ______ birds hard • _____ produce a _____ shell around the egg development is external – outside the female’s body and ______

Fertilization & Development in Other Organisms Non-placental Mammals – Egg Laying Mammals internal fertilization Egg laying mammals - have _____ • __________ Soft shell • Lay __________ eggs hatched the young are nourished by the • When _____, Mammory glands mother’s __________ • Examples of egg laying mammals are: Duck billed platypus • __________ Spiny anteater • __________

Fertilization & Development in Other Organisms Non-placental Mammals – Marsupials • • marsupials internal fertilization __________ - have _____ • embryo will receive nourishment from pouch the _____ Once in the _____, Mammary glands the mother’s __________ • Examples of marsupials are: inside the female Fertilized egg __________ - begin development _____ yolk of the egg is used for _____ food The _____ embryo leaves the mother’s body and crawls across the A tiny _____ pouch mother’s fur into a _____ • kangaroo koalas ____________________, wombats possums __________, and __________,