 Get
out homework (phases of meiosis
worksheet)
 Fill in Meiosis Mitosis Venn Diagram

Please try to think of at least four differences for
each and two things they have in common
How meiosis is different in males and females.
 Meiosis
in males, process used to create sperm
 Males create four sperm cells for each single
spermatogonium
 Remember the original spermatogonium is diploid,
while the resulting four sperm are
haploid (have half the DNA)
 This process
occurs in the
seminiferous
tubules which make up
the testes
 Seminiferous
tubules are the
little tubes that curl around
to create the testes
 If stretched out these could
reach 300 to 350 meters
 Men can produce an infinite
number of sperm in their life
time.
 They begin producing sperm
at puberty because that is
when the tubes become
hollow
 The
spermatogonium
starts on the outside
of the tube
 As it moves its way
to the inner portion
of the tube it
undergoes meiosis
 The four sperm are
then released into
the inside of the
seminiferous tubule.
 Oogenesis
is meiosis in
females and produces
one egg cell.
 Each round of meiosis
creates one mature
egg cell that can be
fertilized and three
polar bodies, which
cannot be fertilized.
 This process occurs in
the follicles of the
ocary
 Each
female has
about 400,000
primary follicles
in her ovary at
birth.
 A female starts producing egg cells at puberty and cannot
possibly produce more egg cells than she has follicles
 Most female produce about 400 mature eggs in her
lifetime
 During ovulation the egg is released from the ovary so it
can be fertilized

Creates four mature
sperm
Occurs continuously
 Occurs throughout
entire life after
puberty
 Occurs in males
 Sperm are smaller
and motile

Spermatogenesis
Creates one mature
egg and three polar
bodies
 Occurs once a month
 Stops occurring once
menopause is reached

Occurs in females
 Egg is much larger
and not motile

Oogenesis
 Both
are forms of meiosis
 Both create sex cells used in sexual
reproduction
 Both occur in the gonads
 Both start with a diploid cell and end up with
haploid cells.
 Both occur in plants (pollen or spores and
egg instead of sperm and egg) and animals
Most issues during gamete
formation occur during meiosis I
 As a woman gets older there
become more and more genetic
abnormalities in her eggs, which is
why the chances of bearing a child
with birth defects increase as a
woman gets older.
 Sometimes during meiosis the
chromosomes do not separate
causing the egg or sperm to either
have 46 or 0 chromosomes
 Sometimes only one pair of
chromosomes does not separate
causing the egg or sperm to have
47 or 45 chromosomes.

 Sometimes
sperm do not
form properly
 When this occurs it can
lead to infertility
 Even though sperm are
being produced, they might
be slow or not motile.
 This causes them to die
before they could possible
reach the egg