Reproduction

Asexual Reproduction Without fusion of gametes Types: Fission – splitting into two Budding – new org grows off of another org Fragmentation – new org develops from piece of other org (accompanied by regeneration) Parthenogenesis – org develops from unfertilized egg (all offspring female)

Hermaphrodites Produce both egg and sperm Primarily organisms that are sessile, burrow or are parasites May self fertilize, most cross fertilize Some species have sequential hermaphrodism

Fertilization Union of egg and sperm May be: External: eggs released into wet environment then male fertilizes Internal: sperm is deposited in or near female reproductive tract Adaptation of terrestrial animals Pheromones – chemical signals released by organisms that influence other members of same species

Male Reproductive System Seminal vesicle (Rectum) Vas deferens Ejaculatory duct Prostate gland Bulbourethral gland (Urinary bladder) (Pubic bone) Erectile tissue of penis Urethra Glans penis Prepuce Epididymis Testis Scrotum Male Reproductive System Figure 46.10 Erectile tissue of penis Prostate gland (Urinary bladder) Bulbourethral gland Vas deferens Epididymis Testis Seminal vesicle (behind bladder) Urethra Scrotum Glans penis Seminiferous tubules Leydig cells Baculum

Female Reproductive System Vagina Uterus Cervix Ovaries Oviduct Uterine wall Endometrium Follicles Corpus luteum Prepuce (Rectum) Cervix Vagina Bartholin’s gland Vaginal opening Ovary Oviduct Labia majora Labia minora (Urinary bladder) (Pubic bone) Uterus Urethra Shaft Glans Clitoris Figure 46.9

Female Reproductive System Ovaries Follicle Ovulation Corpus luteum Oviduct Uterus Endometrium Cervix Vagina Vulva Labia majora/labia minora clitoris

Male Reproductive System Testis Epididymis Scrotum Vas deferenes Seminal vesicle Prostate gland Urethra Penis

Primary germ cell in embryo Gametogenesis Ovary Primary germ cell in embryo Differentiation Oogonium in ovary Mitotic division Primary oocyte, arrested in prophase of meiosis I (present at birth) Completion of meiosis I and onset of meiosis II Primary oocyte within follicle Secondary oocyte, arrested at meta- phase of meiosis II First polar body Ovulation Entry of sperm triggers completion of meiosis II Ovum Growing Mature follicle Ruptured Ovulated secondary oocyte Corpus luteum Degenerating corpus luteum 2n n Figure 46.11 Spermatogenesis Continuous & prolific Occurs in seminiferous tubules 100-650 million sperm cells/ ejaculation Oogenesis Unequal cytokinesis Polar bodies degenerate Not throughout lifetime Lone resting periods

Menstrual Cycle Menstrual Humans & primates If fertilization doesn’t occur: endometrium is shed (menstration) Copulate through cycle Cycle is 20-40 days (ideally 28) Ovulation occurs after endometrium thickens to allow implantation

Ovarian & Uterine Cycle Figure 46.13a–e Control by hypothalamus Inhibited by combination of estrogen and progesterone Stimulated by high levels of estrogen Inhibited by low levels of estrogen Hypothalamus Anterior pituitary GnRH FSH LH Pituitary gonadotropins in blood FSH and LH stimulate follicle to grow LH surge triggers ovulation Ovarian cycle Growing follicle Mature follicle Corpus luteum Degenerating corpus luteum Estrogen secreted by growing follicle in increasing amounts Progesterone and estrogen secreted by corpus luteum Follicular phase Luteal phase Ovulation Ovarian hormones Peak causes LH surge Estrogen Progesterone Estrogen level very low Progesterone and estro- gen promote thickening of endometrium Uterine (menstrual) cycle Endometrium Menstrual flow phase Proliferative phase Secretory phase 5 10 14 15 20 25 28 Days 1 (a) (b) (c) (d) (e) 3 6 7 8 4 2 9 Ovarian & Uterine Cycle

Menopause Cessation of ovulation & menstruation Occurs after about 450 cycles (46-54)

Conception, Development & Birth Conception = fertilization Sperm is released into the vagina & swim through the uterus into fallopian tubes. Sperm attaches to binding site around the egg. Sperm and Egg unite to form zygote. Zygote enters mitoses inside the fallopian tube then travels toward the uterus while dividing to form a morula. Morula develops into a Blastocyst which will implant into the uterine wall.

First Trimester (~13 Weeks) Trophoblast  placenta Organogenesis Heart beating – 4 wks All major structures of adult – 8 wks Heart beat by stethescope – end of first trimester Embryo  fetus @ 8 wks 5cm long Changes in mom too

Second Trimester (~14 Weeks) Fetus grows to 30 cm Fetus is active Mom is showing

Third Trimester (~13 Weeks) Fetus grows to 3-4kg & 50 cm long Fetal activity decreases due to space restraints Mom’s organs are compressed and displaced Frequent urination, constipation, back aches

Labor & Birth Oxytocin Stages of Labor Lactation Figure 46.19 Placenta Umbilical cord Uterus Cervix Dilation of the cervix Expulsion: delivery of the infant (detaching) Delivery of the placenta 1 2 3 Labor & Birth Oxytocin Stages of Labor Lactation

Modern Reproductive Technology Fetal testing Congenetial disorders Aminocentesis Chorionic villi sampling Ultrasound Ethics? To terminate pregnancy Infertility Hormone therapy IUI (Intrauterine Insemination) IVF (In vitro fertilization) ZIFT (zygote intrafallopian transfer) GIFT (gamete intrafallopian transfer) $1,000s/attempt

Figure 46.20 Male Female Method Event Production of viable sperm viable oocytes Vasectomy Combination birth control pill (or injection, patch, or vaginal ring) Sperm transport down male duct system Ovulation Abstinence Condom Coitus interruptus (very high failure rate) Sperm deposited in vagina Capture of the oocyte by the oviduct Tubal ligation Spermicides; diaphragm; cervical cap; progestin alone (minipill, implant, or injection) movement through female reproductive tract Transport of oocyte in Meeting of sperm and oocyte in oviduct Morning-after pill (MAP) Union of sperm and egg Implantation of blastocyst in properly prepared endometrium Birth Progestin alone

Early Development

Early Development 3 Stages of Early Development: Implantation Gastrulation Neurulation

1. Implantation

1. Implantation ~Day 6 or 7 Blastocyst attaches itself to wall of uterus. (Embryo secretes enzymes that digest a path into soft tissue of uterine wall)

1. Implantation ~Day 6 or 7 Blastocyst goes through differentiation Blastocyst attaches itself to wall of uterus. (Embryo secretes enzymes that digest a path into soft tissue of uterine wall) Blastocyst goes through differentiation Inner cell mass develops within inner cavity of blastocyst. (This is where the embryo will develop)

2. Gastrulation

2. Gastrulation Inner cell mass of blastocyst will gradually sort into 2 thin layers.

2. Gastrulation Inner cell mass of blastocyst will gradually sort into 2 thin layers. Third layer is produced through cell migration known as gastrulation.

2. Gastrulation Inner cell mass of blastocyst will gradually sort into 2 thin layers. Third layer is produced through cell migration known as gastrulation. The result?

2. Gastrulation Inner cell mass of blastocyst will gradually sort into 2 thin layers. Third layer is produced through cell migration known as gastrulation. The result? Primary germ layers

Primary germ layers 3 cell layers: Ectoderm – Develops into skin and nervous system. Mesoderm – Cells differentiate to form many of the body’s internal tissues and organs. Endoderm – Forms lining of Digestive System and many of Digestive Organs

3. Neurulation

3. Neurulation Development of the nervous system.

From fertilization to baby

From fertilization to baby Morula A fertilized egg divides to form a ball of cells called a morula. This reaches the uterus a few days after fertilization, moved along by cilia, hairlike structures in the lining of the fallopian tube. The early embryo then embeds itself in the uterine lining.

From fertilization to baby Fetus at 10 weeks By this time, the embryo’s cells have developed and grouped together to form tissues and organs. Most organs are formed by eight weeks, and the embryo is now called a fetus. At 10 weeks, the fetus is 2 inches (5cm) long and has facial features and limbs.

From fertilization to baby Fetus at 18 weeks At about this time, the mother may start to feel the baby move. The umbilical cord connects the fetus to the placenta. This pad of tissue attached to the wall of the uterus supplies nutrients to the fetus and removes waste.

From fertilization to baby Fetus at 30 weeks The baby is growing fast now and maturing in preparation for its journey into the outside world. Ultrasound scanning is often used during pregnancy to check fetal health.

From fertilization to baby Newborn baby Once delivered, the baby starts breathing. The umbilical cord is clamped shut and cut, and the baby is then immediately given to the mother to nurse. The remaining stump of umbilical cord falls off a few days later, leaving the umbilicus (belly button).

Growing up: @ 12 months – grasp objects with hands @ 18 months – drinking from a cup @ 2 years – Eat with fork and spoon @ 3 years – Eat with knife and fork @ 4 years – Brushing their own teeth @ 5 years – Ready for school

Puberty: Occurs between ages of 10-14 in girls & between ages 12-15 in boys. Hormonal changes promote rapid growth, changes in body shape, and development of the reproductive organs. Girls – menstrual cycle begins (eggs are inside girls from birth) Boys – testes start to produce sperm