Name:
Aim 39: Fertilization, Development and Reproductive Technologies
I.
Date:
Fertilization and Zygote Formation
Gametes are formed in the ___________________during ______________. Each gamete contains a
____________ combination of genetic material. During fertilization in the ________________, the gametes unite
to form a single celled _______________. The zygote contains all of the genetic information needed by the
offspring. This process is known as __________________, since the genes from both parents recombine when
fertilization occurs. Both meiosis and fertilization provides ________________ in the organism and plays a key
role in the evolutionary change and the ________________ of the species.
c) _________________
a) ____________
b) _____________
d) __________________
1. Compare & contrast gametes and a zygote. Include where they are formed and the # of chromosomes
2. How does fertilization maintain and restore the chromosome number for humans for future
generations?
3. Humans undergo (internal/external) fertilization and (internal/external) development
II.
Early Development
Human Development Timeline
Time
Day 0
Day 1
Day 2
Day 4
Day 8-9
Event/# Cells
The one-celled zygote contains all of the information necessary for growth, development and the reproduction of
an organism. Once the single celled zygote is formed, it divides by _________________ (cleavage) forming the
early developing _________________. Each cell that is formed by mitotic cell division begins to undergo a
process called __________________________.
Differentiation: A process that occurs in the ______________________ and causes cells to become different
from one another and have _____________________ functions (job), resulting in the formation of
_______________ and ______________.
1
2
3
4
a) Between which two numbers does fertilization occur?
b) Between which two numbers does differentiation occur?
c) Fertilization does not occur after which number?
d) Which number represents cells formed by meiosis?
e) Which process allows all of the cells to divide after the zygote is formed?
f) Which number shows where the greatest amount of organ formation occurs?
g) How is the growth of a human embryo similar to the process of reproduction of a single cell?
h) Place these stages in the correct order from 1st to last on the line below
IMPORTANT: All cells of the developing embryo have __________________ genetic instructions, however
_______________ parts of the instructions are being ________________ in each cell. Certain genes are
________________________ in some cells and not others because of ____________________ and the fact that some
cells may be exposed to different __________________ conditions that allow each cell to develop differentl
III.
Human Development
_______________ or pregnancy is the process of carrying a fetus. The human gestational period is ____
months, or _________ weeks. After early embryonic development and mitotic cell division, embryonic
development continues in the __________________. During development, important features form.
* Embryo: from the time of fertilization until the end of the ____________________ (8th week)
* Fetus: after _______ months when all the major ________________ have formed
*Baby: after carrying a fetus for 9 months, the mother undergoes a series of ______________________, which
pushes the baby out of the womb (labor).
1
* It is important to note that the mother’s blood and developing fetus’s blood DO NOT MIX during development.
Their blood systems are SEPARATE. The materials pass from one to another by diffusing through the placenta.
Structure
1.
Function
Soon to be ___________ offspring that results after the __________________ stage.
Goes through the phases of _______________ before birth.
2.
Cordlike structure containing ___________________________ that attaches the
_____________ to the _______________
3.
Allows essential_______________ and _____________ to diffuse from mother to fetus.
Allows wastes, such as ___________________ to be excreted from the fetus through the
mother.
4.
Where the ______________ unite and the single celled _____________ divides by
______________
5.
___________ filled sac that holds and _______________ a fetus in the womb
IV.
Problems During Human Development
The following images show early developmental stages, demonstrating certain traits that appear at different times of the
development process.
1. How many systems start to form as early as 3 weeks?
2. Which body system forms last?
3. Which week(s) show an embryo?
Which week(s) show a fetus?
4. Why is the fetus most vulnerable to the effect of harmful environmental factors and other toxins during the first 3
months of pregnancy?
5. What are examples of environmental factors/toxins that affect fetal development?
***Examples of Harmful Environmental Factors and Toxins Affecting Fetal Development***
1.
Can lead to fetal alcohol syndrome (FAS). ______ birth weight, facial
abnormalities, damage and low functioning of the ______________
2.
Can lead to low birth ______________, birth ________________, drug
________________, damage to the _________________
3.
4.
Can lead to ________________ and _____________________________ babies
Pathogen (bacteria or virus) can pass from the mother to the fetus through the
______________________, causing an ________________________ in the
fetus. (Measles, AIDS, hepatitis etc.)
5.
Can cause defects in the _________________ of developing fetus
6. What can a mother do during pregnancy to allow the fetus to have a proper and healthy development?
V.
Reproductive Technologies
1. Amniocentesis
Extracting ________________________________ from the _______________________________. This fluid
contains __________ shed by the fetus, which can be ___________________ for any chromosomal
abnormalities or genetic disorders of the fetus. This is usually performed between weeks 14-20 of the
pregnancy.
2. Ultrasound
Allows doctors to see ovaries, oviduct, uterus and developing
fetus to detect for _____________________.
3. Hormone Therapy
Woman can be given ______________________________
to increase the number of eggs ____________________ each month.
4. In Vitro Fertilization
Helps women who
__________________ become
pregnant due to problems with their
__________________, ovaries or
other reproductive parts. This involves
extracting _______________ from a
woman’s ovaries, which are then
________________________ in a lab
dish by a man’s sperm, and
_____________________ into a
woman’s uterus.