Fertilization and Development in Humans

Fertilization ______________ the ______________ of the sperm and egg ______________ in the ____________________________ In humans, ______________ and ______________ is ______________ in the body of the ______________. At the moment of fertilization, the egg develops a ____________________________ around itself to prevent other ______________ from penetrating. A fertilized egg is called a ______________ = + Name: ______________ ______________ ______________ Chromosome ______________ ______________ ______________ Number FERTILIZATION RESTORES THE SPECIES NUMBER OF CHROMOSOMES

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

Advantages / Disadvantages of Internal Fertilization Avoid hazards of the _______________ Sperm can only fertilize an egg for a _______________ period of time Eggs are well _______________ Sperm live a _______________ time because they store _______________ food.

Animal Development (A) (B) 1) __________ 2) __________ 3) __________ 4) __________ 11)__________ (C) 9) __________ 10)__________ 8) __________ 7) __________ 6) __________ 5) __________ _____________________________________

Cleavage __________ - after fertilization, the __________ divides by __________ to produce __________ cells Cell division continues without __________ Once cleavage begins, the zygote is called an __________ __________ - hollow ball formed by the embryo __________ - when the embryo attaches to the ____________________

Gastrulation _______________ - embryo cells become __________ from one another They form __________ and __________ of the new organism DIFFERENT __________ TURN ON OR OFF IN CERTAIN CELLS TO PRODUCE DIFFERENT __________ THE _____________ A CELL MAKES, DETERMINE ITS _______________ Three embryonic germ layers of the embryo __________ - develops into __________ and ____________________ __________ - develops into __________ and __________ systems __________ - develops into __________ other systems like the __________ and __________ systems

Growth in the Uterus __________ - __________ the embryo and__________ the embryo, holds in a fluid called ____________________ __________ - organ responsible for the __________, by __________, of __________ and __________ from the mother’s __________ to the fetus. __________ from the fetus __________ to the mother’s blood through the __________. The mother’s and fetus’ blood ____________________ ____________________ - attaches the __________ to the __________. Contains ____________________ that connect the embryo’s __________ system to the __________ of the placenta

Reproductive Technology Reproductive technology has greatly changed the way we can deal with problems involving _______________ of humans as well as other plants and organisms. Agriculture scientists have produced plants resistant to __________, _______________, or even __________ Resistant plants can be __________ to produce more resistant crops _________________________ - used to reproduce farm animals that exhibit genetic advantages ____________________ - enables infertile women to become pregnant ____________________ - eggs are extracted from an infertile woman and __________ with sperm in a laboratory dish. The ____________________ are implanted into the woman’s uterus, and a _______________pregnancy may result. _______________ and ____________________ allow doctors to view __________, __________, and other reproductive structures

Invitro Fertilization

Amniocentesis _______________ - procedure to extract fluid from around the developing fetus Doctors analyze the cells in the __________ fluid _________________________ and ____________________ can be detected that may threaten the health of the developing fetus

Dangers that face a Fetus The __________ prevents most infections that make the mother ill from passing to the fetus __________ - passes through the tissues of the mother and may affect the fetus __________ - damages the dividing __________ of the fetus _________________________ - found within the mother can enter the fetus ____________________ by the mother affects development in the fetus and may produce underweight babies Exposure to __________ or __________ are also harmful to the fetus Use of __________, __________, LSD, and __________ during pregnancy can cause serious results ____________________ and ____________________ can result from __________ and __________ passing from the mother’s blood to the fetus

Fertilization & Development in Other Organisms Fish and Amphibians Fertilization is __________ Females lay __________ numbers of eggs in the water This ensures the __________ of the species Males will __________ sperm over the eggs in the water to fertilize them Advantages Disadvantages Moist surroundings Egg and sperm may not __________ Eggs may be __________ Changes in _________________ may destroy the eggs and sperm (__________, ________________, and ________________________

Fertilization & Development in Other Organisms Birds and Reptiles In birds and reptiles, fertilization is __________, within the female’s reproductive tract __________ produce a __________ shell around the egg and ____________ is external – outside the female’s body __________ produce a __________ shell around the egg and ____________ is external – outside the female’s body

Fertilization & Development in Other Organisms Non-placental Mammals – Egg Laying Mammals ____________________ - have __________ fertilization Lay ____________________ eggs When __________, the young are nourished by the mother’s ____________________ Examples of egg laying mammals are: ____________________

Fertilization & Development in Other Organisms Non-placental Mammals – Marsupials ____________________ - have __________ fertilization ____________________ - begin development __________ the female The __________ of the egg is used for __________ A tiny __________ leaves the mother’s body and crawls across the mother’s fur into a __________ Once in the __________, the __________ will receive nourishment from the mother’s ____________________ Examples of marsupials are: ____________________, ____________________, ____________________, and ____________________,