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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) __________ cell embryo 5) __________ 4 cell embryo blastula gastrula 8) __________ 7) __________ 6) 8__________ Fertilization A. _____________________________________ Cleavage by mitosis B. _____________________________________ Gastrulation and differentiation C. _____________________________________ Cleavage cleavage - after fertilization, the __________ zygote divides • __________ mitosis to produce __________ two by __________ cells 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 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 • ultrasound and ____________________ Miniature cameras allow doctors to view _______________ 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 toxins or __________ chemicals are also harmful to the Exposure to __________ fetus alcohol during heroine __________, cocaine LSD, and __________ Use of __________, pregnancy can cause serious results addiction Mental retardation can result ____________________ 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 • In birds and reptiles, fertilization is __________, the 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 __________ • pouch the __________ embryo will receive nourishment from Once in the __________, Mammary glands the mother’s ____________________ • 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 __________ Examples of marsupials are: • kangaroo koalas ____________________, ____________________, wombats possums ____________________, and ____________________,
