Reproductive System in Animals

• Reproduction involves two types: sexual and asexual reproduction
• Sexual reproduction involves the mating of two parent organisms and the union of male and female gametophytes
• Asexual reproduction only requires a single parent organism and no union of gametophytes takes place
• Advantages of sexual reproduction include increased genetic diversity, resistance to disease, more evolution, and decreased recessive disorders
• Disadvantages of sexual reproduction include longer gestational period and dependency of offspring
• Animal groups that reproduce sexually include mammals, birds, fishes, and most amphibians and reptiles
• Gametogenesis is the process by which specialized cells known as gametes (eggs and sperm) are created
• Spermatogenesis is the process in males where spermatogonia divide to create haploid sperm cells
• Oogenesis is the process in females where oogonia divide to create a single functioning egg cell
• Fertilization is the joining of sperm and egg to create a zygote
• Reproductive behaviors in sexual reproduction include copulation, mating displays, mate selection, and courtship rituals
• Asexual reproduction methods include budding, binary fission, fragmentation and regeneration, and parthenogenesis
• Animal groups that reproduce asexually include starfish, sea stars, hydra, cnidarians, planarians, and flatworms
• Asexual reproduction leads to rapid spread of advantageous traits within the population
• Human sexual reproduction involves the fusion of specialized sex cells (gametes) from a male and a female
• Male reproductive system includes testes, epididymis, van deferens, seminal vesicles, prostate gland, bulbourethral glands, and penis
• Female reproductive system includes ovaries, fallopian tubes, uterus, cervix, and birth canal
• Fertilization is the union of the female's egg and the male's sperm to create a zygote
• Pregnancy is the development of the blastocyst into an embryo and then a fetus over nine months
• Birth involves the uterine muscles contracting, the baby passing through the birth canal, and the severing of the umbilical cord