Which method of reproduction produces identical offspring and is most successful in a stable environment?
- asexual reproduction
Which method produces genetically-unique offspring?
- sexual reproduction
Which of the following statements is false?
- Budding is a method of asexual reproduction.
- Fragmentation is a method of asexual reproduction.
- Parthenogenesis is a type of sexual reproduction that produces diverse offspring.
- Binary fission is a method of asexual reproduction.
Sea stars are broken apart by workers to save the clams they feed on, and then thrown back into the ocean. Often the numbers of sea stars are seen to double after this. Give the reason why this happens.
- the presence of suitable conditions
Which form of reproduction might be utilized by a sexually reproducing animal that has limited mobility?
In sexual reproduction, gametes with either an X or Y chromosome are formed in males, whereas gametes in females contain a single X chromosome. What is the nature of both male and female gametes?
External fertilization most commonly occurs in which type of environment?
Why is broadcast spawning considered advantageous?
- Production of many eggs increases the chance of fertilization.
- Production of many sperm increases the chance of fertilization.
- It results in mixing of genes and greater genetic diversity.
- Animals that are motile carry out this process.
Which term applies to egg development outside the female with nourishment derived from a yolk?
How are the offspring of viviparous animals different from the offspring of oviparous animals?
- They are protected from the external environment.
- They are produced in higher numbers.
- They can live longer.
- They can utilize nutrients better.
Which of the following structures is involved in mating in birds?
The spermatheca, which is found in many insects, worms, and mollusks, is useful for _____.
- sperm motility
- growth of embryos
- storing sperm and as a site for fertilization
Which part of the male reproductive system produces most of the semen?
- seminal vesicles
- seminiferous tubules
- prostate gland
How is an oocyte released from a human ovary so it can enter the oviduct?
- the beating action of the flagellum on the oocyte
- the force of the follicular ejection directing the oocyte into the oviduct
- the wavelike beating of cilia lining the oviduct
- muscular contraction of the ovaries
Which female organ has the same embryonic origin as the penis?
- labia majora
- greater vestibular glands
Which structure is only related to the male urinary system, as opposed to the male reproductive system?
- urinary bladder
- cowper’s gland
- bulbourethral gland
How many eggs are produced as a result of one meiotic series of cell divisions?
Which of the following events activate the germ cells at puberty to produce spermatozoa?
- activation by gonadotropin-releasing hormone
- activation by increased hair growth
- increase in blood volume
- increase of secretion of testosterone
What stimulates Leydig cells in the testes to produce testosterone?
In both males and females, the hormones FSH and LH play a critical role in the reproductive phase. What regulates the secretion of these hormones?
Which hormone prepares the endometrial lining of the uterus for potential implantation?
With the onset of menopause, the follicles stop responding to which of the following hormones?
- estradiol and progesterone
- progesterone and estrogen
- FSH and LH
- FSH and GnRH
After ovulation, increasing amounts of _____ cause the endometrium to start to thicken.
What characterizes the acrosomal reactions?
- The sperm degrades the outermost layer of the egg to penetrate it.
- motility of the sperm
- fusion of the egg and sperm
- breakdown of the envelope covering the sperm head
What occurs as a result of fertilization of an egg and sperm?
- Fertilization restores diploidy.
- Fertilization always results in a viable embryo.
- Fertilization merges two diploid cells into a haploid cell.
- Fertilization precedes ovulation.
Which of the following statements regarding early embryonic stages is false?
- The endoderm, mesoderm, and ectoderm are germ layers.
- The trophoblast is a germ layer.
- The inner cell mass is a source of embryonic stem cells.
- The blastula is often a hollow ball of cells.
Gastrulation is the process in which the cells in the blastula rearrange themselves and form three layers of cells. Each layer will differentiate into a different organ system. At what point of development do the major organs begin to develop?
- first trimester
- second trimester
- third trimester
What happens to the number of cells during cleavage?
- doubles with every cell division
- does not change significantly
The blastula stage is a mass of specialized cells. Of the following, which forms the liver cells?
- inner cell mass
Which germ layer forms the skin cells?
What are the three phases of embryonic development in chronological order?
- blastula → gastrula → cleavage
- blastula → cleavage → gastrula
- cleavage → gastrula → blastula
- cleavage → blastula → gastrula
Which of the following does not describe axes of symmetry in animals?
Which of the following statements best summarizes the factors controlling symmetry?
- Axis formation is genetically determined.
- Body symmetry is independent of genes.
- Body symmetry is determined at the blastula stage.
- Body symmetry is determined as the embryo grows in length.
The neural plate undergoes folding and movement of cells to form which structure?
- neural tube
- neural cord
What is necessary for normal human fertilization to occur?
- Many eggs must be released.
- The uterus must be enlarged.
- One sperm needs to penetrate one egg.
- Secretion of pituitary FSH and LH must decrease.
Before pregnancy, progesterone is produced by the ovaries to thicken the endometrial lining and ensure pregnancy. During the third trimester of pregnancy, which organ produces progesterone?
- endometrial lining
- corpus luteum
Which hormone is primarily responsible for the contractions during labor?
What happens before the baby and placenta are expelled?
- Thinning and dilation of the cervix take place.
- There is increased blood flow to the baby.
- Enlargement of the uterus takes place.
- Increased production of estrogen occurs.
Which type of short-term contraceptive method is generally more effective than others?
- hormonal implants
- natural family planning
Which of the following best indicates that a female is ovulating?
- slight decrease in body temperature
- decrease in cervical volume
- more pliable cervical secretions
- change in breast size
Fertility is generally unaffected by_____.
- sexually transmitted diseases
- obstruction of reproductive tubes
- drug use
- genetic factors
What occurs in the procedure known as in vitro fertilization (IVF)?
- A sperm is injected into the egg externally.
- An egg is fertilized by the sperm internally in the oviduct.
- Eggs and sperm are combined externally and then implanted.
- Egg and sperm are combined externally and the resulting embryo is implanted.