Module 1A

• In some way or another, all plants and animals around the world reproduce as a way of bringing in new generations and slowly initiating changes in the species
• The fertilization process occurs both in plants and in animals
• Reproduction is also carried out by vertebrate animals via sperm and eggs
• Reproduction


  The biological mechanism by which the parents create new species known as the offspring
• Modes of reproduction


  • Asexual reproduction
  • Sexual reproduction
• Asexual reproduction


  Reproduction by a single parent
• Sexual reproduction


  Reproduction by two parents of opposite sex
• Types of asexual reproduction


  • Binary fission
  • Budding
  • Fragmentation
  • Parthenogenesis
• Binary fission


  The DNA of the parent replicates itself and the cell divides into two halves, each half having its own DNA
• Budding


  The offspring grows on the parent body from a bud-like structure
• Fragmentation


  The parent organism splits into several fragments or segments, where each fragment evolves into a new organism
• Parthenogenesis


  The female organism generates eggs without fertilization, and the offspring emerge from that
• Types of asexual reproduction in plants

  • Vegetative propagation
• Vegetative propagation

  Asexual reproduction that takes place in the stems of certain plants from certain buds that emerge on their leaves or stems, giving rise to new plants
• Sexual reproduction


  Reproduction that involves two separate parents that belong to the opposite sex
• Parts of a flower

  • Calyx
  • Corolla
  • Androecium
  • Gynoecium
• Calyx


  Green petal-like structures located right above the receptacle that safeguard the flower while it is still in the bud process
• Corolla


  The collective colorful petals of the flower that attract pollinating agents
• Androecium


  The male reproductive section of a flower, made up of a series of stamens
• Gynoecium


  The female reproductive organ of the flower, composed of the ovary, style, and stigma

  
• Pollination and Fertilization


  1. Pollen grains travel to reach the stigma

  2. Fertilization occurs after pollination and germination, where the male gametes (pollen) fuse with the female gametes (ovum) to form a diploid zygote
• Types of fertilization


  • Porogamy
  • Chalazogamy
  • Mesogamy
• Porogamy


  The common type of fertilization in angiosperms, where the pollen tube enters the ovule through the micropyle
• Chalazogamy


  The type of fertilization carried out in Casuarina species, where the pollen tube enters the ovule through the pollen tube
• Mesogamy


  The type of fertilization seen in Cucurbit plants, where the pollen tube enters the ovule through its middle part or through the integuments of the ovule
• Double fertilization


  The fusion of two male gametes with a female gametophyte, where one sperm cell fuses with the egg to produce the zygote and the other fuses with the two polar nuclei to produce the endosperm
• Parts of the male reproductive system

  • Penis
  • Scrotum
  • Testicles
  • Epididymis
  • Vas deferens
  • Seminal vesicles
  • Prostate gland
  • Bulbourethral (Cowper's) glands
• Penis


  The male organ for sexual intercourse and urination
• Scrotum


  A loose, pouch-like sack of skin that covers the testicles and hangs behind the penis, maintaining optimum temperatures for sperm production
• Testicles


  The site of testosterone production and where spermatogenesis takes place
• Epididymis


  Binds to the vas deferens and stores and carries sperm
• Vas deferens


  Transports mature sperm to the urethra during ejaculation
• Seminal vesicles


  Produce molecules that serve as energy sources for sperm
• Prostate gland


  Adds extra fluid to the ejaculate, which acts as sperm nourishment
• Bulbourethral (Cowper's) glands


  Contain a slick, clear fluid that lubricates the urethra and neutralizes residual urine-related acidity
• Parts of the female reproductive system

  • Uterus
  • Ovaries
  • Vagina
  • Labia
  • Clitoris
  • Urethra

  
• Uterus


  Hosts the fetus that is developing, produces vaginal and uterine secretions, and passes sperm through to the fallopian tubes
• Ovaries


  Produce eggs and secrete progesterone and estrogen
• Urethra (Cowper's) glands


  Pea-sized structures situated just below the prostate gland on the sides of the urethra
• Fluid produced by Cowper's glands


  Slick, clear fluid that lubricates the urethra and neutralizes residual urine-related acidity