Reproduction

• Reproduction


  Important for the perpetuation of a species
• If there were no means of Reproduction, individuals of a species would not exist anymore and their species would die
• Through Reproduction, New generations are produced
• Asexual reproduction


  Involves a single parent, results in offspring that are genetically identical to each other and to the parent
• Methods of asexual reproduction


  • Binary fission
  • Fragmentation
  • Budding
• Sexual reproduction


  Is the creation of a new organism by combining the genetic material of two organisms, offspring will have traits of both parents but will not be exactly like either parent
• Male reproductive organs


  A pair of testes, two sperm ducts, and a penis
• Sperm


  Male gametes produced by the testes, have a head, a middle section, and a tail
• Female reproductive organs


  A pair of ovaries, oviducts (fallopian tubes), and the uterus

  
• Ovary


  Produces ova, which are female gametes (eggs)
• Fertilization


  The fusion of a sperm and an ovum, the nuclei of the sperm and the egg fuse together to create a single nucleus (zygote)

  
• The new person inherits some of the mother's traits and some of the father's
• In vitro fertilization (IVF)

  Doctors gather newly released egg and sperm and hold them together for a few hours for fertilisation outside the body, the zygote is then implanted in the mother's uterus

  
• Babies born through IVF are known as test tube babies, but they cannot actually develop in test tubes
• Sexual reproduction in animals

  Sex cells are produced during meiosis, the ovaries in the female produce egg cells while testes in the male produce the sperm cells, fertilization occurs when an egg cell and a sperm cell unite to form a zygote

  
• External fertilization


  Eggs and sperm are released into the water, the water becomes the medium in which the sperm swims to unite with an egg

  
• Internal fertilization


  The sperm is transferred directly into the body of the female

  
• In land animals, the sperm has to unite with the egg for fertilization to take place, and the male injects the sperm into the female</b>

  
• The fertilized egg laid by a land animal cannot be left out in the open without protection, the egg contains all the water and nutrients needed by the developing embryo and is protected by a hard, sealed shell
• In internal fertilization, the sperm which the male introduces into the female's body through a process called copulation fertilizes the egg in the female's body

  
• Mammals


  Have mammary glands which the newborn suckle to get milk
• Some mammals like rats and mice have short reproductive cycles, with females coming into "heat" and ready to breed and reproduce every 5 days
• Other mammals have a definite breeding season once a year, when the female will mate with the male
• Mammals differ in the number of offspring, with some producing several at a time and others only one
• Mammalian eggs are much smaller than the eggs of birds and reptiles, and the sperm has a long tail-like flagellum to help it reach the egg
• Hormones


  The testes in males produce testosterone, the ovaries in females produce estrogen
• Oviparous


  Animals that lay eggs, fertilization takes place internally but embryo development takes place externally

  
• Ovoviviparous


  Animals that lay eggs and develop the eggs inside the mother's body, the eggs are hatched inside the mother and the offspring are born live
• Viviparous


  Animals that give birth to offspring, both fertilization and embryo development take place inside the female reproductive system
• Male reproductive system

  Testes produce sperm, sperm travel through sperm ducts and are mixed with fluids from seminal vesicles, prostate gland, and Cowper's glands to form semen, semen is ejaculated through the penis
• Female reproductive system

  Ovaries release eggs that travel through the fallopian tubes, if fertilized the zygote implants in the uterus and develops

  
• Menstrual cycle


  Follicles in the ovary develop and release estrogen, which stimulates the uterine lining, then the follicle releases the egg (ovulation) and secretes progesterone to further thicken the uterine lining, if the egg is not fertilized the lining is shed (menstruation)
• If semen is deposited in the vagina around the time of ovulation, fertilization may occur, with the sperm reaching and penetrating the egg in the fallopian tube

  
• Sperm cells are produced by spermatogenesis in the seminiferous tubules within the testes.
• Flowers


  Responsible for plant reproduction, the reproductive center of the plant
• Sexual reproduction in plants

  1. Flower is where it takes place

  2. Flowering plant produces seeds
• Flower parts


  • Stamen (male reproductive organ)
  • Anther
  • Filament
  • Petal
  • Sepal
  • Stigma
  • Style
  • Pistil (female reproductive organ)
  • Ovary
• Petals


  Brightly colored structure arranged in a circle around the stem's tip
• Stamen


  Flower's male reproductive organ
• Sepals


  Sterile sections of the flower, normally green