Chapter 46 Animal Reproduction AP Biology Perri Pfrommer

Types of Reproduction Asexual Reproduction Sexual Reproduction One parent No sperm & egg fusion Sexual Reproduction Fusion of sperm & egg Sea Anemone Human Couple

Regenerating starfish Asexual Reproduction Types : Fission (most common) Budding Fragmentation (followed by Regeneration) Advantages : Isolated animals can reproduce Many offspring created Regenerating starfish

Other Reproductive Options Switch between Asexual and Sexual Hermaphroditism Male and Female systems Sequential Hermaphroditism Change during lifetime Bees earthworm Blue-head Fish

Fertilization Two Types: Pheromones External Fertilization Moist habitat Lot of zygotes – small # develop Internal Fertilization Adaptation for Terrestrial Animals -> Dry habitat Less zygotes – more develop Pheromones Find a mate Elephant

Ways to Protect Offspring Internal Fertilization’s zygotes have greater protection Tough Eggshells Embryo can develop within reproductive tract Snake Egg Shells Kangaroo Baby-Pouch

Types of Gametogenesis - gamete production Spermatogenesis (Males) Sperm cells Seminiferous Tubes Constant production Oogenesis (Females) Egg cells “resisting” periods

Female Hormones Hormones control Reproductive cycle types of hormones Gonadotropin – releasing hormone (GnRH) Gonadotropin follicle – stimulating hormone (FSH) Luteinizing hormone (LH) Main Female hormones Estrogen Progesterone

Male Hormones Principle Hormone – Androgens Testosterone most important Important part of male development Deeper voice Muscle growth

Embryo Development In 24 hours zygote divides 1 Week reaches embryonic stage – Blastocyst Embryo gives off hormones Human Chorionic Gonadotropin (HCG) Human pregnancy – Three Trimesters, 266 Days

First Trimester 2-4 weeks (Organogenesis) Organs begin developing embryo obtains nutrients Trophoblast and Placenta form (Organogenesis) Organs begin developing 8 weeks – Embryo is a Fetus Changes for Mother as well Ultrasound Photo

Second Trimester Growth/Activity Hormone stabilize Placenta develops Pregnancy becomes Obvious

Third Trimester Activity decrease Mother’s abdominal organs displaced Regulators+Hormones induce labor

Mother’s Immune System does not reject Baby Why?? Hypothesizes – Trophoblast vs. T lymphocytes (T Cells) Releasing molecules with immunosuppressive effects Placenta vs. T Lymphocytes Gives of enzymes

Modern Technology and Pregnancies Ultrasounds Blood Samples from Mother Solutions to infertility problems A.R.T Hormone Therapy