Reproduction

• Asexual Reproduction

  • Involves a single parent

  • Produces genetically identical offspring (clones) 

  • Generally faster and requires less energy

  For example; Bacteria dividing through binary fission can quickly populate a new environment
• Advantages of Asexual Reproduction: 

  • Rapid population growth in favorable conditions 

  • Preservation of well-adapted genotypes 

  • Colonization of new habitats by a single individual
• Sexual Reproduction

  • Involves two parents 

  • Produces genetically diverse offspring 

  • Generally slower and requires more energy

  For Example; Humans reproducing sexually create offspring with unique combinations of traits, potentially better suited to survive in a changing world
• Advantages of Sexual Reproduction: 

  • Generates genetic variation 

  • Increases adaptability to changing environments 

  • Helps eliminate harmful mutations
• Meiosis: 

  • Reduces chromosome number from diploid (2n) to haploid (n)

  • Creates genetic diversity through: 

  • Crossing over (prophase I) 
  • Independent assortment of chromosomes (metaphase I)
• Gamete Fusion (Fertilization):

  • Restores diploid chromosome number 

  • Combines genetic material from two parents
• In humans, meiosis produces haploid sperm (23 chromosomes) and eggs (23 chromosomes). During fertilization, these gametes fuse to create a diploid zygote (46 chromosomes).
• The combination of meiosis and fertilization results in:

  • Breaking up of parental allele combinations 

  • Creation of new allele combinations in offspring 

  • Increased genetic diversity within a population
• Gamete Mobility:

  • Male gamete (sperm) travels to the female gamete (egg) 

  • This mobility requirement leads to key differences in gamete structure and production
• Male Gametes (Sperm):

  • Smaller in size 

  • Produced in large numbers 

  • Contain less cytoplasm and fewer food reserves 

  • Highly motile (typically have a flagellum)