Reproductive Strategies: Sexual vs Asexual Reproduction

Asexual reproduction

Offspring produced from a single parent without gametes.

Sexual reproduction

Offspring produced by joining two haploid gametes.

Budding

New individual forms from a portion of parent.

Regeneration

Complete organism forms from a body fragment.

Parthenogenesis

Development from an unfertilized egg.

Advantages of asexual reproduction

Quickly produce many identical copies.

Disadvantages of asexual reproduction

Less genetic diversity, vulnerable to changes.

Advantages of sexual reproduction

Increased genetic variation enhances survival.

Disadvantages of sexual reproduction

Only half of genes passed to offspring.

Oogenesis

Egg production in females, fewer gametes.

Spermatogenesis

Sperm production in males, more gametes.

Sperm structure

Head contains nucleus; tail provides motility.

Acrosome

Tip of sperm head, contains fertilization enzymes.

Zona pellucida

Jelly-like layer surrounding secondary oocyte.

Cumulus mass

Protective layer providing nutritive support to egg.

Theca

Hormone-producing cells controlling oocyte growth.

Internal fertilization

Sperm deposited in female reproductive tract.

External fertilization

Egg and sperm released into environment.

Fast block to polyspermy

Depolarization of egg membrane prevents multiple sperm.

Slow block to polyspermy

Cortical reaction hardens egg's outer layer.

Acrosomal reaction

Sperm releases enzymes to penetrate egg coat.

Cortical reaction

Cortical granules fuse to egg membrane post-fertilization.

IP3

Stimulates calcium release during cortical reaction.

Calcium release

Triggers exocytosis of cortical granules in egg.

First cell cycle activation

Initiated by calcium release post-fertilization.

Protein synthesis increase

Boosts metabolism after fertilization.

Gametes

Haploid reproductive cells involved in fertilization.

Sperm-binding proteins

Facilitate sperm attachment to egg surface.

Vitelline layer

Surrounds egg, degraded during fertilization.

Environmental change resistance

Ability of populations to adapt to new conditions.

Genetic recombination

Mixing of parental genes during sexual reproduction.