Types of Reproduction

Types of Reproduction

Asexual Reproduction

• Occurs in single-celled organisms, such as bacteria and protists
• Involves the production of genetically identical offspring from a single parent cell
• Methods include:
  • Binary fission: cell divides into two identical daughter cells
  • Budding: new individual grows from a bud on the parent organism
  • Fragmentation: parent organism breaks into fragments, each of which grows into a new individual

Sexual Reproduction

• Involves the fusion of gametes (sex cells) from two parents to form a zygote
• Produces genetically diverse offspring due to crossing over and independent assortment of chromosomes
• Occurs in most multicellular organisms, including animals, plants, and fungi
• Methods include:
  • External fertilization: gametes combine outside the body (e.g., in water)
  • Internal fertilization: gametes combine inside the body (e.g., in animals)

Stages of Sexual Reproduction

Meiosis

• Process by which gametes are produced
• Involves two successive cell divisions, resulting in four haploid gametes
• Key events include:
  • Crossing over: exchange of genetic material between homologous chromosomes
  • Independent assortment: random alignment of chromosomes during cell division

Fertilization

• Fusion of two gametes to form a diploid zygote
• Can occur internally (in animals) or externally (in plants and some animals)

Embryogenesis

• Development of the zygote into a multicellular organism
• Involves multiple cell divisions, growth, and differentiation of tissues and organs

Reproduction

Asexual Reproduction

• Occurs in single-celled organisms like bacteria and protists
• Produces genetically identical offspring from a single parent cell
• Methods:
  • Binary fission: one cell divides into two identical daughter cells
  • Budding: new individual grows from a bud on the parent organism
  • Fragmentation: parent breaks into fragments, each growing into a new individual

Sexual Reproduction

• Involves fusion of gametes from two parents to form a zygote
• Produces genetically diverse offspring due to crossing over and independent assortment of chromosomes
• Occurs in most multicellular organisms, including animals, plants, and fungi
• Methods:
  • External fertilization: gametes combine outside the body (e.g., in water)
  • Internal fertilization: gametes combine inside the body (e.g., in animals)

Meiosis

• Process by which gametes are produced
• Involves two successive cell divisions, resulting in four haploid gametes
• Key events:
  • Crossing over: exchange of genetic material between homologous chromosomes
  • Independent assortment: random alignment of chromosomes during cell division

Fertilization

• Fusion of two gametes to form a diploid zygote
• Can occur internally (in animals) or externally (in plants and some animals)

Embryogenesis

• Development of the zygote into a multicellular organism
• Involves multiple cell divisions, growth, and differentiation of tissues and organs