Chapter 12
Reproduction and Development
Preview
Section 1 Animal Reproduction
Section 2 Human Reproduction
Section 3 Growth and Development
Concept Mapping
Chapter 12
Section 1 Animal Reproduction
Bellringer
Do you know how birds, ants, humans, and sea
stars reproduce? Write down any differences that
you are aware of in how these animals reproduce.
Also write down any differences that you know of
in how these animals raise their young.
Write your answers in your science journal.
Chapter 12
Section 1 Animal Reproduction
Objectives
• Distinguish between asexual and sexual
reproduction.
• Explain the difference between external and internal
fertilization.
• Identify the three different types of mammalian
reproduction.
Chapter 12
Section 1 Animal Reproduction
Asexual Reproduction
• In asexual reproduction, a single parent has
offspring that are genetically identical to the parent.
• Budding, fragmentation, and regeneration are all
ways in which a parent organism can produce
genetically identical offspring.
Chapter 12
Section 1 Animal Reproduction
Sexual Reproduction
• In sexual reproduction, offspring are formed when
genetic information from more than one parent
combines.
• Sexual reproduction in animals usually requires two
parents—a male and a female.
• The female parent produces sex cells called eggs.
The male parent produces sex cells called sperm.
Chapter 12
Section 1 Animal Reproduction
Sexual Reproduction, continued
Chapter 12
Section 1 Animal Reproduction
Internal and External Fertilization
• External Fertilization is the process when the
sperm fertilizes the eggs outside the female’s body.
• Internal Fertilization is the process when the egg
and sperm join inside the female’s body.
Chapter 12
Section 1 Animal Reproduction
Mammals
• Monotremes are mammals that lay eggs.
• Marsupials are mammals that give birth to
partially developed live young. Most marsupials
have pouches where their young continue to
develop after birth.
• Placental Mammals are nourished inside their
mother’s body before birth.
Chapter 12
Section 2 Human Reproduction
Bellringer
Do you think that cloning human beings could be
considered reproduction? Why or why not? What
kind of reproduction is it?
Record your answers in your science journal.
Chapter 12
Section 2 Human Reproduction
Objectives
• Identify the structures and functions of the male
and female reproductive systems.
• Describe two reproductive system problems.
Chapter 12
Section 2 Human Reproduction
The Male Reproductive System
• The male reproductive system produces sperm and
delivers it to the female reproductive system.
• The testes are a pair of organs that make sperm and
testosterone.
• Testosterone is the main male sex hormone. It helps
regulate the production of sperm and the development
of male characteristics.
Chapter 12
Section 2 Human Reproduction
Chapter 12
Section 2 Human Reproduction
The Female Reproductive System
• The female reproductive system produces eggs,
nurtures fertilized eggs (zygotes), and gives birth.
• The two ovaries are the organs that make eggs.
• Ovaries also release estrogen and progesterone,
the main female sex hormones. These hormones
regulate the release of eggs and development of
female characteristics.
Chapter 12
Section 2 Human Reproduction
Chapter 12
Section 2 Human Reproduction
The Female Reproductive System, continued
• The Egg’s Journey During ovulation, an egg is
released from an ovary and passes into a fallopian
tube. If the egg is fertilized, the resulting zygote
enters the uterus.
• When a baby is born, he or she passes through the
vagina and emerges outside the body.
• The menstrual cycle is a series of monthly changes
that prepares the body for pregnancy.
Chapter 12
Section 2 Human Reproduction
Menstrual Cycle and Uterine Lining
Click below to watch the Visual Concept.
Visual Concept
Chapter 12
Section 2 Human Reproduction
Multiple Births
• Twins, Triplets, Quadruplets, and More In every
1,000 births, there are about 30 sets of twins. In the
United States, there are about two sets of triplets in
every 1,000 births. Births of quintuplets or more
happen only once in about 53,000 births.
Chapter 12
Section 2 Human Reproduction
Reproductive System Problems
• STDs A sexually transmitted disease (STD) is a
disease that can pass from one person to another
during sexual contact.
STD
Approx. # of new cases each year
Chlamydia
3 to 10 million
Genital HPV
5.5 million
Genital herpes
1 million
Gonorrhea
650,000
Syphilis
70,000
HIV/AIDS
40,000 to 50,000
Chapter 12
Section 2 Human Reproduction
Reproductive System Problems, continued
• Cancer Sometimes, cancer happens in reproductive
organs. Cancer is a disease in which cells grow at an
uncontrolled rate.
• Infertility In the United States, about 15% of married
couples have difficulty producing offspring. Many of
these couples are infertile, or unable to have children.
Chapter 12
Section 3 Growth and Development
Bellringer
Name the stages of physical development that you
have gone through in your life so far. What is the next
stage of development that you will go through? List
some physical and social changes that will happen
during this next stage. Are you looking forward to
this future stage of life?
Record your thoughts in your science journal.
Chapter 12
Section 3 Growth and Development
Objectives
• Summarize the processes of fertilization and
implantation.
• Describe the development of the embryo and
the fetus.
• Identify the stages of human development from
birth to death.
Chapter 12
Section 3 Growth and Development
From Fertilization to Embryo
• A fertilized egg (zygote)
travels down the fallopian
tube toward the uterus.
Eleven to 12 days after
fertilization, the zygote
has become a tiny ball of
cells called an embryo.
Then implantation occurs.
Implantation is the
embedding of the embryo
in the thick, nutrient-rich
lining of the uterus.
Chapter 12
Section 3 Growth and Development
From Embryo to Fetus
• The placenta is a special
two-way
exchange organ. It has a
network of blood vessels
that provides the embryo
with oxygen and nutrients
from the mother’s blood.
Wastes produced by the
embryo are removed in the
placenta.
Chapter 12
Section 3 Growth and Development
From Embryo to Fetus, continued
• Weeks 1 and 2 Doctors commonly count the time of
a woman’s pregnancy as starting from the first day of
her last menstrual period.
• Weeks 3 and 4 In week 3, after fertilization, the
zygote moves to the uterus. As the zygote travels, it
divides many times. At the end of week 4, implantation
is complete and the woman is pregnant.
Chapter 12
Section 3 Growth and Development
From Embryo to Fetus, continued
• Weeks 5 to 8 In this stage, the embryo becomes
surrounded by a thin membrane called the amnion. The
umbilical cord forms. The heart, brain, other organs,
and blood vessels start to form.
• Weeks 9 to 16 At week 9, the embryo may begin to
make tiny movements. After week 10, the embryo is
called a fetus. The embryo grows rapidly during this
stage.
Chapter 12
Section 3 Growth and Development
From Embryo to Fetus, continued
• Weeks 17 to 24 By week 17, the fetus can make
faces. By week 23, the fetus’s movements may be
quite vigorous!
• Weeks 25 to 36 At about 25 or 26 weeks, the
fetus’s lungs are well developed. By the 32nd week,
the fetus’s eyes are open and perceive light through
the mother’s abdominal wall.
Chapter 12
Section 3 Growth and Development
Pregnancy Overview
Click below to watch the Visual Concept.
Visual Concept
Chapter 12
Section 3 Growth and Development
Birth
• A full-term pregnancy usually lasts about 40 weeks.
Typically, as birth begins, the mother’s uterus begins a
series of muscular contractions called labor. Usually,
these contractions push the fetus through the mother’s
vagina, and the baby is born.
Chapter 12
Section 3 Growth and Development
From Birth to Death
• Infancy to Childhood Generally, infancy is the
stage from birth to age 2. Childhood—another
period of fast growth—lasts from age 2 to puberty.
• Adolescence The stage from puberty to
adulthood is adolescence. During puberty, a
person’s reproductive system becomes mature.
Chapter 12
Section 3 Growth and Development
From Birth to Death, continued
• Adulthood From about age 20 to age 40, you will
be a young adult. Beginning around age 30,
changes associated with aging begin.
• The aging process continues in middle age
(between 40 and 65 years old). A person who is
more than 65 years old is considered an older adult.
Chapter 12
Section 3 Growth and Development
Chapter 12
Reproduction and Development
Concept Mapping
Use the terms below to complete the concept map on
the next slide.
fragmentation
Reproduction
sexual reproduction
internal fertilization
an embryo
zygote
egg
budding
asexual reproduction
Chapter 12
Reproduction and Development
Chapter 12
Reproduction and Development