Reproduction of Animals

• Reproduction


  The process of producing offspring that are biologically or genetically similar to the parent organism
• All organisms eventually die, but reproduction ensures the perpetuity of the species
• Types of Reproduction


  • Asexual Reproduction
  • Sexual Reproduction
• Asexual Reproduction


  The type of reproduction in which only a single organism gives rise to a new individual, without the fusion of gametes, resulting in genetically identical offspring
• There is no variation or differences in asexual reproduction, as the offspring are genetically similar to their parents
• Types of Asexual Reproduction

  • Binary Fission
  • Budding
  • Fragmentation
  • Parthenogenesis
• Binary Fission


  1. Organism divides into two, each part carrying one copy of genetic material

  2. DNA duplicates

  3. Cytoplasm divides into two to form two daughter cells
• Examples of Binary Fission

  • Paramecium
  • Bacteria
• Budding


  A new organism develops from an outgrowth or bud due to cell division at one particular site, remaining attached as it grows and separating from the parent organism only when it is mature
• Fragmentation


  A form of asexual reproduction wherein a parent organism breaks into fragments, each capable of growing independently into a new organism
• Examples of Fragmentation


  • Starfish
  • Planarian
• Regeneration


  Occurs when an organism regrows a lost limb or any other part of the body
• Parthenogenesis


  Growth and development of embryos without fertilization
• Sexual Reproduction


  A haploid sperm cell and a haploid egg cell unite to form a diploid zygote
• Scrotum


  A part of the male reproductive system that houses the testes, with a temperature lower than normal body temperature to support sperm production
• Sperm Cell


  • Head (contains nucleus and genetic material)
  • Midpiece (packed with mitochondria for energy)
  • Tail (used for motility)
• Egg cells are non-motile, in contrast to the motile sperm cells
• Ovaries


  Release mature egg cells that can be fertilized by sperm in the fallopian tube, forming a zygote that implants in the uterus for embryonic development
• Uterus


  The part of the female reproductive system where the zygote implants and the embryo develops
• Ectopic pregnancy occurs when the embryo implants in the fallopian tube instead of the uterus, leading to miscarriage
• Mechanisms of Fertilization


  • Internal Fertilization
  • External Fertilization
• Internal Fertilization


  Fusion of gametes occurs inside the female body, providing better protection and higher chances of survival for the offspring
• External Fertilization


  Fusion of gametes occurs outside the female body, exposing the offspring to predators and harsh environments
• Types of Internal Fertilization

  • Oviparous (egg-laying)
  • Viviparous (live birth)
  • Ovoviviparous (egg-laying with internal development)
• Oviparous animals lay eggs that hatch to produce young, Viviparous animals carry their young inside their body until birth, and Ovoviviparous animals lay eggs that hatch inside the mother's body
• Stages of Mammalian Animal Development

  • Fertilization
  • Cleavage
  • Gastrulation
  • Neurulation
  • Organogenesis
• Modes of Nutrition


  • Autotrophic (self-feeding)
  • Heterotrophic (feeding on other organisms)
• Photoautotrophic


  Organisms that use energy from the sun and inorganic substances like carbon dioxide and water to produce their own food through photosynthesis
• Chemoautotrophic


  Organisms that use chemicals in the environment to create simpler organic substances for their survival
• Heterotrophic


  Organisms that depend on other organisms for their food and nutrition
• Saprophytic or Saprotrophic


  Organisms that obtain nutrients from dead organic matter by secreting digestive juices and absorbing the nutrients
• Parasitic


  Organisms that take food from another organism, classified as ectoparasites (outside the host) or endoparasites (inside the host)
• Types of Heterotrophic Nutrition

  • Herbivorous (plant-eating)
  • Carnivorous (meat-eating)
  • Omnivorous (plant and meat-eating)
  • Granivorous (seed-eating)