BIOL 114
Ch. 26 Reproduction and Development
26.1 Mind-Boggling births
I.
Describe some problems that multiple-birth newborns face.
26.2 How Animals Reproduce and Develop
I.
Asexual Reproduction
A. How do the offspring compare with the parent, both genetically (i.e., in gene makeup) and phenotypically (i.e., in physical looks)?
B. Would organisms that reproduce asexually survive better in an environment that is
relatively unchanging or in an environment that is constantly changing? Explain
why.
C. Parthenogenesis is an asexual reproduction method used by insects, fish, amphibians,
and lizards. Describe parthenogenesis.
II.
Sexual Reproduction
A. How do the offspring compare with the parents, both genetically (i.e., in gene makeup) and phenotypically (i.e., in physical looks)?
B. Would organisms that reproduce sexually survive in an environment that is constantly
changing (resources, predators, weather)? Why?
III.
Variations on Sexual Reproduction
A. How may hermaphrodites reproduce?
B. How do aquatic invertebrates, fishes, and amphibians guarantee that external
fertilization of eggs and sperm occur?
C. How do reptiles and mammals guarantee that internal fertilization of eggs and sperm
occur?
1. Do animals that reproduce via internal fertilization produce more gametes or
fewer gametes than animals that reproduce via external fertilization?
IV.
Stages in Reproduction and Development
A. Gamete formation
1. In sexually reproducing animals, which cell division process makes haploid cells
that will mature into gametes?
2. To connect with concepts learned in Ch 8: in human males, where are sperm
formed?
3. To connect with concepts learned in Ch 8: in human females, where are ova
formed?
B. Fertilization
1. When sperm nuclei fuse with egg nuclei, the one celled structure formed is called
a __________.
2. The cytoplasm of the zygote is mostly the cytoplasm of the __________.
C. Cleavage
1. The zygote begins to divide by the cell division process of __________ during
this stage.
2. Even though cells are dividing during this stage, and the number of cells does
increase, does the original fertilized egg’s volume change?
3. The repeated cell divisions result in a ball of cells called a __________.
a. To connect with concepts learned in Lab 5: you observed a whitefish blastula
to find cells in different stages of mitosis.
D. Gastrulation
1. Cells rearrange themselves into three primary tissue layers during gastrulation.
What will cellular descendants of the ectoderm layer become?
2. What will cellular descendants of the mesoderm layer become?
3. What will cellular descendants of the endoderm layer become?
E. Organ formation
1. A cell in the ectoderm and a cell in the mesoderm have the same amount of DNA.
Yet, how is it possible that the ectoderm cell becomes a skin cell and the
mesoderm cell becomes a muscle cell?
F. Growth and tissue specialization
1. What happens in this stage?
26.3 Human Reproductive system
I.
Male Reproductive System
A. Which male reproductive organs make sperm and male hormones?
B. Because of the location of male testes, would sperm develop best at temperature
below or above body temperature (37 0C)?
C. Sperm production begins during puberty. List some other characteristics of a young
boy entering puberty.
D. Pathway of sperm
1. From the testes, sperm cells take about 12 days to go to the _________, where
they complete maturation and are stored.
2. During ejaculation, muscles in the walls of epididymides push the sperm cells into
the __________ __________, into __________ __________, and out the tube in
the penis called urethra.
3. On the way out the urethra, sperm will mix with nutrient-rich secretions.
a. Which glands secrete fructose-rich fluid into the vasa deferentia? These
glands secrete about 70 % of the fluid in semen. Why do sperm require
fructose?
b.
Which gland encircles the urethra and secretes fluid into the urethra? How
do this gland’s secretions influence the pH of the female reproductive tract
and for what reason?
c.
Which glands (about the size of a pea) add a thick mucus to the urethra so
that the mucus clears the urethra of urine prior to ejaculation?
E. Name the second most common fatal cancer in men. Which cancer is the most
common fatal cancer in men?
II.
How sperm form
A. Seminiferous tubules inside men’s testes contain diploid germ cells called
spermatogonia. These cells are diploid in chromosome number and are capable of
__________ (mitosis or meiosis?) to produce many more of these cells for the man’s
entire life.
B. If spermatogonia are activated to enter meiosis, they will differentiate into primary
spermatocytes. When primary spermatocytes divide by meiosis I, what cells are
formed?
C. Secondary spermatocytes undergo meiosis II to produce four haploid immature sperm
cells called spermatids. [note: the term spermatids is not used in textbook]
D. Over a period of two and a half months, the spermatids mature into __________.
E. To connect with concepts learned in a previous section: in which structures do
spermatids mature into sperm?
F. Are sperm haploid or diploid in chromosome number?
G. What structure does a sperm cell use to propel itself?
H. Hormones
1. The hypothalamus secretes GnRH, which stimulates the __________
__________ cells to secrete LH and FSH.
2. Describe the function of LH in males.
3. Describe the function of FSH in males.
III.
Female Reproductive System
A. Which female reproductive organs produce oocytes and sex hormones?
B. When a secondary oocyte is released from the ovary, it enters one of a pair of tubes
called __________ , where fertilization usually occurs if sperm were present.
C. If an embryo does form, where does the embryo develop for 38-40 weeks?
D. The narrowed portion of the uterus that connects to the vagina is called the
__________.
IV.
Egg Formation and the Ovarian Cycle
A. A girl is born with approximately __________ 2 million primary oocytes.
B. These primary oocytes are in __________ phase of meiosis I.
C. Describe ovarian follicle.
D. In the early stages of the ovarian cycle, describe what the follicle cells are doing.
E. In the follicle that has the fluid-filled cavity, what does the primary oocyte finish?
[notes: about 8-10 hours before ovulation, the primary oocyte does this] To form
which two cells? Differentiate between the sizes of these two cells. Which process
was unequal to produce the different sizes?
F. The secondary oocyte starts meiosis II but halts in __________.
G. About midcycle, the follicle wall ruptures and releases __________ into the
__________.
H. When should the secondary oocyte meet up with sperm for fertilization to occur?
I. Only when fertilization does occur would the secondary oocyte finish __________.
J. After ovulation, the ruptured follicle develops into a __________ __________.
V.
Hormones and the Menstrual Cycle
A. The menstrual cycle refers to cyclic changes in the __________.
B. A typical menstrual cycle may last ___ days, plus or minus a few days.
C. Days 1-13 [note: this is called the follicular phase]
1. The first day of the menstrual cycle is evidenced by menstruation. What is
menstruation?
2. The hypothalamus secretes GnRH, which stimulates the anterior pituitary to
releases FSH. How does FSH influence the ovarian follicle?
3. As the follicle matures, cells secrete the sex hormone __________ and a little
progesterone.
4. Rising levels of estrogen corresponds to the thickening of the __________.
D. Day 14 [note: this is called the ovulation phase]
1. The steep rise in estrogen levels triggers the anterior pituitary to produce a steep
rise __________ around mid-cycle.
2. The LH surge triggers the primary oocyte to finish __________.
3. The LH surge also triggers the follicle to swell and burst, resulting in
__________.
E. Days 15-28 [note: this is called the luteal phase]
1. Estrogen levels _________ temporarily until the corpus luteum forms.
2. The corupus luteum produces mainly the sex hormone __________, plus a little
estrogen.
3. How do estrogen and progesterone affect the uterine lining?
4. During the luteal phase, high levels of estrogen and progesterone prevents the
hypothalamus from secreting __________, so that no other follicles begin
maturing.
5. When the corpus luteum begins to break down, what happens to levels of estrogen
and progesterone? The change in estrogen and progesterone levels causes the
uterine lining to __________, which brings the cycle back to day 1.
VI.
Menstruation-Related Disorders
A. Name some symptoms of premenstrual syndrome (PMS).
B. Provide possible solutions for PMS.
C. Menstrual cramps are caused by contractions of __________.
D. Will a woman menstruate anymore or be able to have children when she completes
menopause?
26.4 How pregnancy happens
I.
Fertilization
A. About how many sperm enter the vagina when a man ejaculates?
B. Where would sperm need to go to fertilize a secondary oocyte?
C. How many sperm enter the secondary oocyte?
D. Sperm entry will prompt the secondary oocyte to complete what stage of meiosis?
E. The nucleus of the ovum that forms and the nucleus of the sperm fuse during
fertilization to create a zygote. Would a zygote have a diploid or haploid nucleus?
26.5 Fertility and Reproductive Health
I.
Contraception
A. What is the most effective form of contraception?
B. From the example methods of contraception provided in Table 26.1, which one is the
least effective?
C. Vasectomy and tubal ligation are effective surgical methods. Describe the surgery
required for each method.
D. How do IUDs work?
E. Which method is used by at least 50 million people in the U.S. and thus is considered
the most common contraceptive method?
1. How do birth control pills work?
2. Which cancers may birth control pills protect against?
3. Which cancers may birth control pills increase the risk of?
II.
Abortion
A. Approximately how many fertilized eggs abort spontaneously?
B. Which drug (used with a prostaglandin) may induce abortion during the first nine
weeks of pregnancy? How does this drug work?
III.
Assisted Reproduction
A. How does in vitro fertilization work?
B. In 30-year-old women, what is the success rate of in vitro fertilization?
C. In 40-year-old women, what is the success rate of in vitro fertilization?
IV.
Overview of Sexually Transmitted Disease
A. How might having an STD affect fertility and fetal development?
V.
Common STDs
A. HPV infection is one of the most widespread and fastest spreading STDs in the U.S.
The concern about HPV is that a few strains of HPV are the main cause of
__________ cancer. How may young girls prevent themselves from HPV infection
in the future? Is HPV a virus, bacterium, fungi, or protist?
B. Trichomonas vaginalis causes trichomoniasis. Is Trichomonas vaginalis a virus,
bacterium, fungi, or protist?
C. What type of organism (i.e., virus, bacterium, fungi, protist) causes chlamydia? Forty
percent of those who get chlamydia are in what age range? Name the type of
medicine that kills this organism.
D. What type of organism causes genital herpes? Once infected by this organism, does it
stay with you for life?
E. What type of organism causes gonorrhea? Name the type of medicine that cures
gonorrhea.
F. What type of organism causes syphilis? Name some symptoms in the various stages
of syphilis.
G. What disease results if you are infected with HIV?
26.6 Human Prenatal Development
I.
Where does fertilization take place?
II.
Cleavage and Implantation
A. Days 1-3
1. Cleavage of the zygote happens when the zygote divides by the process of
__________ and cytoplasmic division as it moves down the oviducts.
B. Day 4
1. The cluster of 16 cells that forms is called a __________.
C. Day 5
1. The blastocyst contains a few hundred cells as an outer layer, a cavity, and an
inner cell mass. The future embryo develops from which of these?
D. Days 6-7
1. The blastocyst is in the uterus. Explain implantation.
E. Days 10-11
1. The amniotic cavity and amnion membrane surround the embryonic disk. What is
the importance of the fluid that is inside the amniotic cavity?
2. Which types of cells are derived from cells in the yolk sac?
F. Days 12-14
1. Part of the allantois and part of the chorionic villi form part of the __________,
which is the main source of nutrition for the embryo and fetus.
G. The chorion secretes human chorionic gonadotropin (HCG), which prevents the
degeneration of the __________ __________. Because this structure is maintained,
it still produces two hormones, __________ and __________, which maintain the
uterine lining.
III.
Embryonic Development: in lab, we will watch a video on this amazing process
IV.
Fetal Development
A. The term fetus is used when all organ systems are in place. At which week after
fertilization is the embryo called a fetus?
V.
Functions of the Placenta
A. Maternal blood and the blood inside the chorionic villi do not mix. How do nutrients
and oxygen from maternal blood get into embryonic blood?
B. By the third month, which hormones does the placenta produce and for what reason?
VI.
Maternal Effects on Prenatal Development
A. As a precaution, why should pregnant women not change a cat’s litter box?
B. Why should pregnant women never consume alcohol?
C. If a pregnant woman is taking prescribed medications for acne or depression, she
should always discuss with her __________ before going off any medications.
26.7 From Birth Onward
I.
The Process of Birth
A. When the amnion breaks, how would a pregnant woman experience this?
B. Name the hormone responsible for increasing contractions during labor.
26.8 Mind-Boggling Births
I.
Differentiate between how fraternal and identical twins form.