The remainder of today’s content focus on mammalian reproduction, featuring humans as a model organism. The information below was adapted from OpenStax Biology 43.3 Mammalian (Human) Reproductive Anatomy, Gametogenesis, and Hormonal Regulation The uterus has two chambers in species that produce large numbers of offspring at a time, while species that produce one offspring, such as primates, have a single chamber. Mammals have separate openings for the systems in the female, and placental mammals have a uterus for support of developing offspring.Ducks are a rare exception, where the males have a penis. Mating between birds usually involves positioning the cloaca openings opposite each other for transfer of sperm from male to female. Non-mammal vertebrates, such as most birds and reptiles, have a cloaca: a single body opening w hich functions in the digestive, excretory and reproductive systems.Fertilization can be timed with environmental or food conditions that are optimal for offspring survival. In some invertebrate species, including many insects and some mollusks and worms, the female has a spermatheca: a specialized sac which stores sperm for later use, sometimes up to a year.Of course, beyond this general anatomy, there are some interesting differences in different types of animals: The first half of Hank Green’s video below has a nice summary of these and other ideas we’ve discussed previously, and the second half introduces human reproductive anatomy before we take a deep dive into the structures and functions via dynamic hormonal regulation:įor our purposes, all sexual reproducers have females with ovaries that produce large eggs, which subsequently travel down a uterine tube, and males with testes that produce small, plenteous sperm, stored in an epididymus. When the eggs are released from the ovary, they travel to the uterine tubes for fertilization (in animals that reproduce via internal fertilization) or are released in the aqueous environment (in animals that reproduce via external fertilization). Eggs are large cells that require a substantial investment of time and energy to form, are non-mobile, and are rare relative to sperm numbers. Females produce an ovum or egg that matures in the ovary. Sperm are small, mobile, low-cost cells that occur in high numbers. In animals ranging from insects to humans, males produce sperm in testes, and sperm are stored in the epididymis until ejaculation. The reproductive structures of many animals are very similar, even across different lineages, in a process that begins with two gametes–eggs and sperm–and ends with a zygote, which is a fertilized egg. The information below was adapted from OpenStax Biology43.2 Diversity of Animal Reproductive Anatomy
Explain how various medical interventions affect reproductive cycles and fertilization.Describe roles of hormones in gametogenesis, ovulation, and implantation.Compare and contrast the process, products, and locations of male and female gametogenesis in mammals.Identify and describe functions of key anatomical reproductive structures present in various types of animals, including the spermatheca, the cloaca, the ovary and related structures, and the testes and related structures.
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