Reproduction In Vertebrates - SS2 Biology Past Questions and Answers - page 2

Sperm

Ova

Prostate gland

Cervix

Fishes employ various reproductive strategies, including external fertilization, internal fertilization, oviparity, and viviparity. External fertilization in fishes involves the release of eggs and sperm into the water, allowing fertilization to occur externally. This strategy ensures a higher chance of successful fertilization due to the large number of gametes released. It also allows for genetic diversity and enables offspring to disperse widely.

Reptiles exhibit various reproductive modes, including oviparity, ovoviviparity, and viviparity. Reptiles have internal fertilization, and most species lay shelled eggs. Some reptiles exhibit temperature-dependent sex determination, where the temperature during incubation determines the sex of the offspring. Additionally, reptiles have specialized structures, such as cloacae, for copulation and the deposition of eggs.

 Birds reproduce through internal fertilization. Male birds transfer sperm to the female through a specialized opening called the cloaca during a behavior known as a cloacal kiss. Female birds have a unique reproductive tract with a single functional ovary and oviduct. They lay hard-shelled eggs and exhibit various mating systems and courtship behaviors.

The male reproductive system in mammals includes the testes, epididymis, vas deferens, seminal vesicles, prostate gland, and penis. The testes produce sperm cells, which mature in the epididymis and are transported through the vas deferens during ejaculation. The seminal vesicles and prostate gland produce seminal fluid that nourishes and transports sperm. The penis serves as the organ for copulation and sperm delivery.

The female reproductive system in mammals consists of the ovaries, fallopian tubes, uterus, cervix, and vagina. The ovaries produce ova (eggs), which are released into the fallopian tubes. Fertilization of the egg typically occurs in the fallopian tubes. If fertilization occurs, the resulting embryo implants in the uterus, where it develops into a fetus. The cervix serves as the entrance to the uterus, and the vagina functions as the birth canal and copulatory organ.

Sperm cells are produced in the testes through a process called spermatogenesis. Spermatogenesis involves the continuous production and maturation of sperm cells through several stages, including mitotic division, meiosis, and spermiogenesis. Spermatogonia undergo mitosis to produce primary spermatocytes, which then undergo meiosis I and meiosis II to generate haploid spermatids. These spermatids further mature into sperm cells through spermiogenesis, where they develop flagella and acrosomes for motility and fertilization.