Sex Organs and Sexual Reproduction

• Sex organs are explored by examining animal mating, specifically Koalas
• The levels of organization that make up an organism are: cells, tissues, organs, organ systems, and the organism itself.

Determining Sex

• Sex is observed and recorded by doctors at birth using primary sex characteristics like sex organs and sex cells.
• Other factors that affect these characteristics include: genes, hormones, chromosomes, and physical secondary sex characteristics.
• Sex characteristics vary with a range from typical male to typical female.
• Intersex variations are when bodies differ from the most common expressions of male and female.
• Gender differs from sex and is a range of socially constructed roles, behaviors, and identities that may change.
• Male and female describe the typical sex characteristics described at birth.

Sexual Reproduction

• Sexual reproduction is the creation of new organisms through the fusion of sperm and egg cells from two individuals of the same species.
• Animals use complementary male and female sex organs for sperm and egg cells to meet.
• Sex organs vary across the animal kingdom and have developed to best suit the species mate, environment, and life cycle.

Male Human Sex Organs

• Vas deferens: Transports mature sperm to the penis and also called the "sperm duct".
• Epididymis: Stores and develops immature sperm cells produced in the testes.
• Testis: Produces immature sperm cells, also called "testicle".
• Seminal vesicles: Produce a sugar-rich liquid to help sperm travel.
• Prostate gland: Produces more fluid to help nourish the sperm.
• Penis: Delivers sperm to the female and also allows the removal of urine from the body.
• Urethra: Transports sperm and urine out of the body.

Female Reproductive Systems

• Fallopian tube: Transports eggs from the ovary to the uterus.
• Ovary:
  • Releases an egg when stimulated by mating.
  • Releases an egg every month.
• Uterus: Houses and nourishes a fertilized egg and developing fetus.
• Cervix: The narrow opening of the uterus.
• Vagina: A tube of muscles connecting the cervix to the outside of the body.
• Oviduct: Transports eggs from the ovary to the uterus.
• Vaginas (Koala): The two outer vaginas transport sperm up to the uterus; the central vagina is used to give birth.
• Cloaca (Koala): The single external opening of the reproductive, urinary, and digestive systems found in many animals.

Koala vs Human

• Humans external opening is the Vagina and Koalas external opening is the Cloaca
• Both species have two ovaries
• Humans have one Uterus and Koalas have 3 vaginas
• Koala releases an egg only after mating, and humans release an egg every month

Penis role

• The primary function of the penis is to deliver sperm to the female
• The shape of the human penis complements the female reproductive system because it is long and cylindrical, making it easy to fit into the female vagina.

Koala Penis

• The Koala penis has two heads because the Kola reproductive system has two vaginal areas for the penis.

Hyenas

• Female spotted hyenas have pseudo-penises that are just as large as male penises and can become erect.
• During mating, the female's "penis" retracts in on itself, forming a pocket for the male's penis.
• When the female gives birth, the offspring travels down the long birth canal through the middle of the pseudo-penis.

Plant Sex Organs

• In plants, male sex cells (pollen) deposit on the stigma and move down the style to the ovary.