Lesson 1: Reproduction & Development Tuesday, March 13 AIM: How do animals reproduce? What is the anatomy of the human male reproductive system? DO NOW: Distinguish between calcitonin & PTH. HW: Study all notes and hormones Read Ch. 13 in review book MC packet on Ch. 46 # 1-18 Hormone QUIZ Wednesday

Asexual Reproduction Advantages: No mate needed Lots of offspring produced quickly If environment remains favorable, clones are a good thing. Disadvantages: No variation – offspring identical to parents

5 Types of Asexual Reproduction Binary fission (prokaryotes) Budding (Hydra & yeast) Fragmentation and regeneration Lower left – 2 mitochondria budding 3

Parthenogenesis (honeybees, some lizards, some amphibians) Specialized cells  new organism (gemmules in sponges) In parthenogenesis, there is a doubling of chromosomes after meiosis. 4

Sexual Reproduction Hermaphroditism Gonads non-mammalian vertebrates: Cloaca –common opening to the digestive, excretory, and reproductive systems Internal vs. external fertilization Internal vs external development

Human Male Reproductive System

Human Male Reproductive System Testes in scrotum (20 lower than body temperature) seminiferous tubules – FSH from ant pit stimulates sperm production interstitial cells (Leydig cells) – LH from ant pit stimulates testosterone production Sertoli cells -- nourish spermatids Epididymus -- maturation and storage of sperm

Spermatogenesis in seminiferous tubules Spermatogonium (2n) Primary spermatocyte (2n) Secondary spermatocyte (n) Spermatid (n) Sperm (n)

Vas deferens – transfer sperm from epididymus to urethra

Vasectomy Severing of vas deferens Method of birth control

Caveat Do not confuse seminiferous tubules with seminal vesicles.

Sperm Sperm head – haploid nucleus – 23 chromosomes Acrosome –tip–-- has lysosymes to penetrate egg Midpiece – first part of the flagellum – many mitochondria – Tail – last part of flagellum