Reproduction BIO 201: Organismal S&F Dr. Tony Serino Misericordia Univ. Biology Dept.

Asexual Reproduction Generation of new individuals without union of gametes Budding Fission –separation of parent into two individuals (invertebrates) Budding –outgrowth of a new individual from an existing one (invertebrates) Fragmentation and Regeneration –breaking body of parent into several pieces and then regrowth of each into functional organism (invertebrates) Parthenogenesis –an unfertilized egg develops into an adult (invertebrates and vertebrates) Fission Parthenogenesis

Sexual Reproduction Production of sex cells (gametes) that fuse to begin forming a new individual Most animals have cyclic reproduction activity that correspond to favorable environmental conditions for raising offspring Controlled by hormones that vary with day length, season, temperature, rainfall and.or lunar cycles

Sexual Pattern Variations Hermaphroditism –an individual with functional male and female sexual anatomy. Usually encounters results in both individuals being insemintated, but in some cases an individual may mate with itself Sex Reversal –some species living in a same sex environment can change from one sex to another (crocs, some fish, etc.); other animals switch sex to increase their chances in contributing to the next generation (some oysters) Wrasse undergoes sex reversal

External Fertilization

Reproduction System Functions: Survival of species Production of sex cells (gametes) Transport the gametes toward each other Allow gametes to meet (fertilization) Promote the generation, maintenance and rearing of progeny

Gonads: undergo Meiosis to produce gametes Meiosis (divided into Meiosis I and II) Meiosis I Assorts chromosomes by homologous pairs Then separates the pairs randomly Reduces the number of chromosomes by half; Diploid to Haploid (2n  n) Meiosis II Separates sister chromatids Progeny cells now have one DNA per chromosome

Male Reproduction Gonads: Testis Gamete: Spermatozoa (sperm) Duct system: to store and transport sperm from gonad to external environment Supporting structures: Allow sperm maturation Allow survival of sperm in ext. environment Deposit sperm into female vagina Sensory functions

Male Reproductive Anatomy

Spermatogenesis

Male Hormones

Female Reproduction Gonad: Ovary Gametes: Ova Duct System: Transport ovum from ovary to uterus Site of fertilization; Receive and transport sperm to ovum Capacitate sperm House and support fetus Deliver fetus Supporting Structures Sensory and protective functions

Female Anatomy (oviduct or Fallopian tube) Vulva

Oogenesis * * First polar body may not divide to form others.

Development of Ovum and Follicle

Ovulation Secondary oocyte Zona Pellucida Corona Radiata

Oviduct (Uterine or Fallopian tube) Ampulla Isthmus Functions: transportation of ovum, sperm and zygote -capacitation of sperm -site of fertilization

Uterus: houses and supports fetus

Female Hormones Hypothalamus secretes GnRH Anterior Pituitary secretes FSH and LH Theca cells of ovary secrete estrogens Granulosa cells secrete inhibin Luteal cells (modified granulosa cells) secrete progesterone

Ovarian and Uterine Cycles

Estrous Cycle -Estrous period of sexual readiness for the female; corresponds and may trigger sexual behavior of males -different species have different timing patterns and number of estrous cycles per season