Reproduction Asexual- Fission- Budding- Fragmentation- Separation of the original parent into 2 or more http://www.dnai.org/text/mediashowcase/index2.html?id=590 Budding- New individual splits off from a larger original http://etic.univ-reunion.fr/hydroids/animaux_sarsia_reproduction.htm Fragmentation- Breaking of body into several pieces Advantages of asexual Reproduction: Very efficient- lots in a short period of time Perpetuates a successful genotype Disadvantages: You know!!! Loss of variation!!!

Sexual Reproduction Bring on the variation! External Fertilization- Eggs are shed by Female, then fertilized by the male. AQUATIC Occurs almost exclusively in a(n) _______________ habitat. Internal Fertilization- Sperm is deposited in or near the female reproductive tract, fertilization then occurs within the female body. Invertebrate vs Vertebrate: Invertebrate- Range from very complex …to very simple systems without any distinct gonads. Examples: Insects have a “spermatheca” Earthworms are hermaphroditic, but still “copulate”.

Sexual Reproduction in Vertebrates: Some have a common opening for digestive, excretory, and reproductive “products” Called a cloaca http://www.vpi.com/images/118 There is a complex interplay of hormones and organ responses which regulate reproduction: Estrous cycles occur in non-primate mammals If pregnancy does not occur, endometrium gets reabsorbed Involves pronounced behavioral changes and tends to follow seasonal and climatic cues. (cats in heat) Egg & Sperm production in Humans is quite complex: http://health.howstuffworks.com/adam-roundup.htm Menstrual cycles occur in humans and most primates.

The Human Male Testes~ male gonads Seminiferous tubules~ sperm formation Leydig cells~ hormone (tesosterone) production Also called “INTERSTITIAL CELLS” Scrotum~ outside body temp. Epididymis~ sperm storage Vas deferens~ sperm propulsion Seminal vesicles~ provides 60% of semen fluid. Contains amino acids, fructose, and prostaglandins. Prostate gland~ anticoagulant; nutrients, alkaline Bulbourethral glands~ also contains acid neutralizers Penis/urethra~ semen delivery

The Human Female Ovaries~ female gonads Follicle~ egg capsule Corpus luteum~ hormone secretion Oviduct~ fertilization Uterus/endometrium~ womb/lining Cervix/vagina~ sperm receptacle

Spermatogenesis Puberty until death! Seminiferous tubules~ location Primordial germ cell (2N)~ differentiate into…. Spermatogonium (2N)~ sperm precursor Repeated mitosis into…. Primary spermatocyte (2N) 1st meiotic division Secondary spermatocyte (1N) 2nd meiotic division Spermatids (1N) Sperm cells (1N) Weblink!

Oogenesis Oogonia cells multiply and begin meiosis Stops in prophase 1 of meiosis = primary oocyte (2n) until puberty Puberty onward – FSH stimulates follicle to grow and egg cell to complete meiosis I and begin meiosis II = secondary oocyte (n) Secondary oocyte (n) now in Metaphase II, is released at ovulation, upon sperm entry meiosis II is completed Weblink!

The Menstrual / Ovarian Cycle: Hold on tight! Menstruation (endometrium sheds) GnRH from Hypothalamus Corpus Luteum atrophies (if egg not fertilized) Low Estrogen/Progesterone Low LH Signals pituitary to Secrete small amounts of FSH and LH Stops Inhibits FSH & LH production in the pituitary (stops more eggs) Estrogen also causes The endometrium to Thicken. Signals to Ovary to stimulate growth of a follicle. Corpus Luteum secretes Progesterone More estrogen…. More…. MORE….!! Remains of follicle called A Corpus Luteum Follicle secretes Estrogen which causes increased LH & FSH production As follicle grows more & more Estrogen gets produced LH surge from Pituitary. OVULATION!! NOTE: IF egg is fertilized, embryo secretes HCG (Human Chorionic Gonadotropin) which Maintains progesterone/estrogen secretions From corpus luteum so endometrium is still maintained…. Egg D:\bc_campbell_biology