Three Size Lessons: Differences Between Sexual and Asexual Reproduction

Introduction

• Objective: Describe the differences between sexual and asexual reproduction.

Human Cells and Chromosomes

• Human cells contain 23 pairs of chromosomes in the nucleus.
• Diagram Note: Often simplified to show fewer pairs for clarity.

Mitosis

• Mitosis: Process where one cell is copied into two identical cells.

Gametes

• Gametes: Cells with chromosomes not paired (sperm and egg cells in humans).
  • Sperm and Egg Cells: Each contain 23 single chromosomes.
  • Size Note: Sperm cells are much smaller than egg cells.

Meiosis

• Meiosis: Type of cell division that produces non-identical cells.
  • Occurs in both humans and flowering plants (gametes are pollen and egg cells in plants).
  • Unlike mitosis, meiosis results in genetic variation.

Sexual Reproduction

• Involves the fusion (joining) of male and female gametes.
  • This process is known as fertilization.
• Results in mixing of genetic information.
• Leads to variation in offspring due to different gametes.

Asexual Reproduction

• Involves only one parent.
  • Example: Aphids reproducing asexually.
• No gametes involved; no mixing of genetic information.
• Offspring are genetically identical to the parent (clones).
• Only involves mitosis.
• Example: Plants reproducing by forming tiny buds that grow into new plants.

Study Resources

• Mention of a revision workbook available for further practice and questions.