Biology: Concepts and Investigations

Marielle Hoefnagels, Matthew S. Taylor

Chapter 35

Animal Reproduction and Development - all with Video Answers

Educators

Chapter Questions

Problem 1

What is differentiation? How do protein gradients cause cells to differentiate?

Danielle Ashley

Danielle Ashley

Numerade Educator

Problem 2

Some newborn mammals can walk and carry out other life functions independently. Human babies, on the other hand, are born helpless. Speculate about the trade-offs in these two reproductive strategies. What selective forces might limit the stage of development at which humans are born?

Noah Boudrie

Numerade Educator

Problem 3

How are the human male and female reproductive tracts similar, and how are they different? How are the structures of the testis and ovary similar and different?

Danielle Ashley

Danielle Ashley

Numerade Educator

Problem 4

Briefly explain the contradictory roles of estrogen in the human female reproductive cycle.

Hollie Ulibarri

Hollie Ulibarri

Numerade Educator

Problem 5

What are the functions of LH and FSH in males and females?

Danielle Ashley

Danielle Ashley

Numerade Educator

Problem 6

How are the timetables different for oogenesis and spermatogenesis in humans?

Danielle Ashley

Danielle Ashley

Numerade Educator

Problem 7

In many species, a female may mate with multiple males, increasing her chance of conception. Speculate about how this behavior may select for males with faster sperm or more numerous sperm per ejaculate.

Hollie Ulibarri

Hollie Ulibarri

Numerade Educator

Problem 8

Point mutations usually occur during interphase of mitosis, but most chromosomal abnormalities arise during meiosis. Given the differences between gamete production in males and females, why is it reasonable to predict that more point mutations occur during sperm production and more chromosomal abnormalities appear in egg cells?

Alexander Burbelo

Alexander Burbelo

Numerade Educator

Problem 9

Is each of the following cell types haploid or diploid? How does each cell type relate to the others?
a. An oogonium
b. A primary spermatocyte
c. A spermatid
d. A secondary oocyte
e. A polar body derived from a primary oocyte

Alexander Burbelo

Alexander Burbelo

Numerade Educator

Problem 10

Write a paragraph describing the path of sperm to egg, starting with sperm in the epididymis. Hint: See figure 35.25

Noah Boudrie

Numerade Educator

Problem 11

Use the Internet to learn more about sexually transmitted diseases. Choose one to study in detail. What type of infectious agent causes the disease? What are the symptoms and long-term consequences of infection? Is a treatment available? Who is most affected?

Alexander Burbelo

Alexander Burbelo

Numerade Educator

Problem 12

What would happen if two sperm fertilized the same egg cell? If two sperm fertilized two egg cells?

Alexander Burbelo

Alexander Burbelo

Numerade Educator

Problem 13

A zygote is a single cell whose weight is immeasurably small, yet after countless cell divisions it develops into a newborn weighing approximately 3.5 kilograms. While in the uterus, the developing infant obtains the atoms that make up its ever-increasing mass from its mother. Where does the mother obtain these atoms?

Noah Boudrie

Numerade Educator

Problem 14

After ovulation, LH transforms the ruptured follicle into the corpus luteum. As LH levels decline, the corpus luteum degenerates. However, if fertilization occurs, the preembryo starts producing a hormone called hCG, which is similar in structure to LH and prevents the corpus luteum from degenerating. Why is it adaptive for the preembryo to maintain the corpus luteum?

Danielle Ashley

Danielle Ashley

Numerade Educator

Problem 15

For each of the following pairs of phrases, indicate if the first is greater than the second, if the second is greater than the first, or if the two are equal.
a. The number of cells in a morula; the number of cells in a gastrula
b. The thickness of the endometrium after ovulation; the thickness of the endometrium after menstruation
c. The number of eggs released from an ovary during each ovarian cycle; the number of sperm released during ejaculation
d. The number of chromosomes in an egg cell; the number of chromosomes in a sperm cell

Danielle Ashley

Danielle Ashley

Numerade Educator

Problem 16

What is the source of nutrients for a developing preembryo? For an embryo? For a fetus?

Noah Boudrie

Numerade Educator

Problem 17

Provide a general explanation for why men have nipples. Hint: Figure 35.17 may help.

Noah Boudrie

Numerade Educator

Problem 18

Consult a website that describes and illustrates fetal development. What technology do you think would be necessary to enable a fetus born in the fourth month to survive in a laboratory setting?

Danielle Ashley

Danielle Ashley

Numerade Educator

Problem 19

During labor, a baby may remain in the birth canal for hours. How does the baby not suffocate during this time?

Danielle Ashley

Danielle Ashley

Numerade Educator

Problem 20

Most physicians clamp and cut the umbilical cord immediately after birth, separating the baby from the nutrients and respiratory gases it receives from the placenta; other physicians wait to cut the cord for several minutes after birth, allowing the remaining cord blood to enter the baby's body. Design an experiment to test whether immediate clamping or delayed clamping of the umbilical cord is a better practice for healthy babies.

Danielle Ashley

Danielle Ashley

Numerade Educator

Problem 21

Use the Internet to research the rate of cesarean sections (surgical removal of the baby) in the United States. Why might the incidence be so high?

Danielle Ashley

Danielle Ashley

Numerade Educator

Problem 22

What is the significance of the critical period in determining the type and severity of a birth defect?

Noah Boudrie

Numerade Educator

Problem 23

What kinds of studies and information would be necessary to determine whether exposure to a potential teratogen can cause birth defects a year later? How would such an analysis differ if it were a man or a woman who was exposed?

Danielle Ashley

Danielle Ashley

Numerade Educator