Chapter 47 Reproduction

Question 1

what are some advantages of asexual reproduction?

Answer 1

• no mate necessary
  -many offspring in little time
  -perpetuation of successful genotypes
  -reduction of heterozygosity in population
  -natural selection happens faster
  -works great if sessile

Question 2

what are the main types of asexual reproduction?

Answer 2

budding- new individual grows off on an individual. common in hydra and yeast
gemmules- bundle of archeocytes with spicules, left with internal buds, give rise to new bud
Fragmentation- happens from injury, organism will break into several fragments, each can develop into new organism (starfish and flatworms)
Fission- organism splits into two equal parts, each part develops into new organism. Common in bacteria
Parthenogenesis- process where unfertilized egg develops into a new organisms. common in fish, reptiles, insects.

Question 3

what is TSD?

Answer 3

temperature sex determination. Temperature of incubation determines the sex of the organism.

Question 4

what is GSD?

Answer 4

Genetic sex determination. genetic determine the sex. In birds have W-Z for female and ZZ for males. There is X-Y for mammals, where it is determined by the presence of the Y chromosome, if Y is there then it is male (XY) and (XX) is female. In some insects it is X-O which by the number of sex chromosomes determines sex of the offspring.

Question 5

what is haplodiploidy?

Answer 5

In these species (ants, insects and bees), the offspring will be female if developed from a fertilized egg and have two sets of chromosomes where as males develop from unfertilized eggs and have one set of chromosomes.

Question 6

what is Parthenogenesis?

Answer 6

Using tools of sexual reproduction for asexual reproduction. Genetic material comes solely from the mother, as the egg develops into an embryo without having to be fertilized by a sperm cell.

Question 7

What is myxis ? How does it work?

Answer 7

When a species alternates from male to female. Females produce diploid eggs (females) stress comes along females produce haploid eggs (Males), males fertilize eggs- stay dominant until conditions improve return to female dominant.

Question 7

What is myxis ? How does it work?

Answer 7

When a species alternates from male to female. Females produce diploid eggs (females) stress comes along females produce haploid eggs (Males), males fertilize eggs- stay dominant until conditions improve return to female dominant.

Question 8

What is the relative reproductive investment for males and females in terms of gametes?

Answer 8

females have high reproductive investment while males have low reproductive investment

Question 9

what advantages are there in sexual reproduction?

Answer 9

-increases in genetic variation
-good for changing environments
-good for motile organisms
-larger offspring

Question 10

What does monoecious and dioecious mean?

Answer 10

Monoecious: everybody is the same, one sex
Dioecious: two sexes, male or female

Question 11

What is gonochorism? What is sexual dimorphism?

Answer 11

Gonochorism: individuals can be male or female at any given time, switch sexes
Sexual Dimorphism: male and female look different

Question 12

What is hermaphroditism?

Answer 12

Sequential Hermaphroditism: dioecious, has both male and female parts but at different points in life (e.g. clownfish)
Synchronous Hermaphroditism: monoecious, both male and female gonads at the same time

Question 13

how does sexual dimorphism relate to the idea that “sperm are cheap”?

Answer 13

sperm is easy to make.

Question 14

what are some of the problems with sexual reproduction?

Answer 14

-Cost: it is energetically costly, have to find mate and produce gametes
-Competition: competition between individual mates
-Risks of Diseases
-Limited genetic diversity
-Inefficiency: variably in offsprings traits

Question 15

what are some of the differences in internal and external fertilization?

Answer 15

Internal Fertilization: cooperative behaviour among individuals, cupulation is involved. Occurs inside the female body
External Fertilization: mostly aquatics, synchronous reproduction, male and female must do it at the same time for success, occurs outside the female body

Question 16

Describe spider sex

Answer 16

Dioecious. Males contain pedipalps which they use to deliver sperm on to the female spider. They can break of pedipalps in the female or just on their own. Females have an epigynum which is the external genital structure. The female contains a spermatheca which is where she can hold sperm from a male for up to a year before she decides she wants to use it. Females will do sexual cannibalism which is when she kills male spider after mating.

Question 17

What is the arrangement for openings for digestive, urinary and reproductive systems in mammals?

Answer 17

In mammals the opening for the digestive, urinary and reproductive systems are separate and distinct. The digestive system has two openings: the mouth which leads to the digestive tract and the anus, which is the exit point for undigested food and waste. The urinary has one opening, the urethra, which carries urine from the bladder out of the body. The reproductive system has separate openings for male and females. In males the reproductive opening is the penis, which is used for both urination and ejaculation. In females, the reproductive opening is the vagina which leads to the cervix and then the uterus. The urethra is also present in females, but is separate from the reproductive system and is only used for urination.

Question 18

what are the modes of reproduction in vertebrates?

Answer 18

ovipary- nutritionally independent egg, this is many fish, many reptiles, birds, monotremes (platypus)
ovovivpary- nutritional investment egg, hatches inside the body, this is some reptiles, some fish, some amphibians
vivipary- embryo produced, not nutritionally independent, mother feeds in stomach, this is some fish, some amphibians, most mammals, and some reptiles. live births

Question 19

describe the human anatomy of a male reproductive system.

Answer 19

testes, epididymis, seminal vesicles, prostate glands, bulbourethral glands, penis. meant to deliver sperm to egg.

Question 20

what is lagomorphs?

Answer 20

penis is behind scrotum instead of front. In rabbits, hares, pikas

Question 21

what are seminiferous tubules?

Answer 21

narrow, coiled tubules that produce sperm in the testes.

Question 22

what are leydig cells?

Answer 22

produce testosterone

Question 23

what is the epididymis?

Answer 23

a long, coiled duct on the outside of the testis in which sperm mature.

Question 24

what are seminal vesicles?

Answer 24

contribute mucus, fructose, coagulating enzymes, ascorbic acid, and prostaglandins
~60% semen: contributed by the seminal vesicles.
Prostaglandins: act as a pheromone, thin the mucus at the cervix and stimulate vaginal contraction.

Question 25

what are prostate glands?

Answer 25

Releases anticoagulant enzymes and citrate

Question 26

what are bulbourethral glands?

Answer 26

contribute lubricant fluid to the sperm, and secretions buffer the urethra to neutralize residual acidity

Question 27

what is the penis?

Answer 27

has three layers of spongy erectile tissue
Erectile tissue fills with blood
Pressure seals off the veins
Engorgement causes erection
utilizes the parasympathetic autonomous nervous system, and is therefore involuntary

Question 28

describe the anatomy of the human female reproductive system

Answer 28

ovaries: produce estrogens and follicles (4000), but only a few release eggs. Sit attached to the abdominal cavity
fallopian tube: female organ that connects the ovary to the uterus; place where fertilization usually takes place. Cilia convey the egg to the uterus
uterus:Female organ of reproduction used to house the developing fetus. Where an egg develops if fertilized.
endometrium: lining of the uterus that is highly vascular and continually shed.
cervix: the opening of the uterus
vagina:A muscular, elastic passageway that extends from the uterus to the outside of the body
clitoris:organ of sensitive erectile tissue anterior to the opening of the female urethra

Question 29

What are the males primary and secondary characteristics?

Answer 29

Primary: internal and external reproductive structures, sperm production
Secondary: voice, facial and pubic hair, muscle growth

Question 29

What are the males primary and secondary characteristics?

Answer 29

Primary: internal and external reproductive structures, sperm production
Secondary: voice, facial and pubic hair, muscle growth

Question 30

What are the female primary and secondary characteristics?

Answer 30

Primary: reproductive organs, reproductive cycle
Secondary: fat in the breasts and hips, water retention, affects calcium metabolism, breast development, mediates sexual behaviour: not to the same degree as estrous cycles. Libido is affected during cycles.

Question 31

Describe the female reproductive cycle:

Answer 31

Gonadotropin releasing hormone is released by the hypothalamus. It targets the anterior pituitary and causes it to release LH and FSH. Those stimulate the follicle to grow.
Release of GnRH is stimulated by high estradiol and inhibited by progesterone and estradiol.
Surge in LH causes the egg to be released.
Menstrual cycle: follicle develops, released estradiol (positive feedback mechanism). The luteal phase is the second phase. Corpus luteum releases progesterone and estradiol.
Ovarian cycle: endometrium sloughs off when corpus luteum disintegrates. Endometrium thickens over several weeks.

Question 32

what is the menstrual cycle?

Answer 32

Endometrium is shed = menstruation, causes bleeding and then followed by regrowth of endometrium.

Question 33

What is menopause?

Answer 33

the time of natural cessation of menstruation; also refers to the biological changes a woman experiences as her ability to reproduce declines. Estrogen levels lower, decreased responsiveness to gonadotropins

Question 34

describe the cyclic changes in hormone levels and how they affect the menstrual and ovarian cycles:

Answer 34

primary hormones include FSH (follicle-stimulating hormone), LH (luteinizing hormone), estrogen and progesterone. These are all critical hormones for proper functioning of the menstrual and ovarian cycles. Any disruptions can result in menstrual irregularities or infertility.

Question 35

How to prevent the spread of STIs (sexually transmitted infections)

Answer 35

practice safe sex, get tested, limit # of sexual partners, practice good hygiene.