Reproduction Types Overview

Overview

• Explains the two main types of reproduction: sexual and asexual
• Gives examples and basic mechanisms in animals, plants, and microorganisms

Types of Reproduction

• Reproduction: making more organisms of the same type
• Sexual reproduction: two parents, offspring are unique
• Asexual reproduction: one parent, offspring are genetic clones

Sexual Reproduction

• Most animals use sexual reproduction
• Egg (female) and sperm (male) cells (gametes) fuse in fertilization
• Fertilization forms a zygote with DNA from both parents
• Zygote divides and grows into a new organism
• In flowering plants: male gametes in pollen, female gametes in ovules
• Fertilized ovule becomes a seed, which grows into a new plant

Asexual Reproduction

• One parent produces genetically identical offspring
• Examples in plants:
  • Runners (e.g., strawberries): horizontal stems make new plants
  • Tubers (e.g., potatoes): food-storing stems/roots sprout new plants
  • Bulbs (e.g., onions): underground storage organs make daughter bulbs
• Artificial methods:
  • Cuttings: plant sections grow into new plants
  • Micropropagation: lab technique using plant tissue to make clones
• Microorganisms:
  • Bacteria: binary fission (cell splits in two)
  • Yeast: budding (new cell grows from parent)
• Some animals (e.g., starfish) can regrow parts to form identical individuals

Key Terms & Definitions

• Reproduction: making new organisms
• Sexual reproduction: two parents, unique offspring
• Asexual reproduction: one parent, identical offspring
• Gametes: reproductive cells (egg, sperm, pollen, ovule)
• Fertilization: joining of gametes
• Zygote: cell formed after fertilization
• Runners: horizontal stems making new plants
• Tubers: food-storing plant parts that sprout new plants
• Bulbs: underground storage organs making new plants
• Cuttings: plant pieces grown into new plants
• Micropropagation: lab cloning of plants
• Binary fission: cell splits in two (bacteria)
• Budding: new organism grows from parent (yeast)

Action Items / Next Steps

• Watch the next lecture for a comparison of the advantages of sexual and asexual reproduction