Biology: Types of Reproduction and Meiosis

Types of Reproduction

• Asexual Reproduction: a single parent produces offspring that are genetically identical to the parent
  • Examples: binary fission, budding, fragmentation, regeneration
• Sexual Reproduction: two parents combine their genetic material to produce offspring with unique characteristics
  • Examples: conjugation, gamete formation

Sexual Reproduction Process

• Meiosis: the process by which gametes (sperm and egg cells) are produced
  1. Interphase: cell growth and DNA replication
  2. Prophase I: chromosomes condense and pair up
  3. Metaphase I: paired chromosomes align at the center of the cell
  4. Anaphase I: sister chromatids separate
  5. Telophase I: nuclear envelope reforms
  6. Cytokinesis: cytoplasm divides
  7. Meiosis II: same process as mitosis, but with haploid cells
• Fertilization: the fusion of sperm and egg cells to form a zygote
• Embryogenesis: the development of a zygote into a fetus

Reproductive Strategies

• R-Selection: emphasis on producing many offspring with minimal parental investment
  • Examples: fish, insects
• K-Selection: emphasis on producing few offspring with high parental investment
  • Examples: humans, elephants
• Iteroparity: producing multiple batches of offspring throughout a lifetime
  • Examples: most animals
• Semelparity: producing a single batch of offspring and then dying
  • Examples: salmon, cicadas

Reproductive Systems

• Male Reproductive System: produces and delivers sperm
  • Components: testes, epididymis, vas deferens, urethra, penis
• Female Reproductive System: produces and nurtures eggs
  • Components: ovaries, fallopian tubes, uterus, cervix, vagina

Types of Reproduction

• Asexual reproduction produces genetically identical offspring from a single parent, occurring through methods such as binary fission, budding, fragmentation, and regeneration.
• Sexual reproduction involves two parents combining genetic material to produce unique offspring, examples include conjugation and gamete formation.

Meiosis

Phases of Meiosis

• Interphase: cell growth and DNA replication occur.
• Prophase I: chromosomes condense and pair up.
• Metaphase I: paired chromosomes align at the center of the cell.
• Anaphase I: sister chromatids separate.
• Telophase I: nuclear envelope reforms.
• Cytokinesis: cytoplasm divides.
• Meiosis II: same process as mitosis, but with haploid cells.

Fertilization and Embryogenesis

• Fertilization: the fusion of sperm and egg cells forms a zygote.
• Embryogenesis: the development of a zygote into a fetus.

Reproductive Strategies

• R-Selection: produces many offspring with minimal parental investment, seen in fish and insects.
• K-Selection: produces few offspring with high parental investment, seen in humans and elephants.
• Iteroparity: producing multiple batches of offspring throughout a lifetime, characteristic of most animals.
• Semelparity: producing a single batch of offspring and then dying, seen in salmon and cicadas.

Male and Female Reproductive Systems

Male Reproductive System

• Produces and delivers sperm through components such as testes, epididymis, vas deferens, urethra, and penis.

Female Reproductive System

• Produces and nurtures eggs through components such as ovaries, fallopian tubes, uterus, cervix, and vagina.