sexual Reproduction
Overview of Sexual Reproduction
Involves two parents and the fusion of haploid cells (gametes).
Generally slower and more complex than asexual reproduction.
Common in humans and many organisms.
Sexual Reproduction in Plants
Flower Anatomy
Perfect Flowers: Contain both male (stamen) and female (pistil) reproductive parts.
Imperfect Flowers: Contain only male or female organs.
Parts of a Flower
Ovary: Contains ovules.
Pistil: Comprising stigma, style, and ovary (female part).
Style: Supports the stigma.
Stigma: Receives pollen.
Stamen: Comprising filament and anther (male part).
Anther: Produces pollen grains (male gametes).
Petal: Attracts pollinators.
Filament: Holds anther.
Sepal: Encloses the developing bud.
Pollination
Types:
Self-Pollination:
Autogamy: Same flower.
Geitonogamy: Different flowers of the same plant.
Cross-Pollination: Different plants (also xenogamy).
Leads to fertilization, forming zygote from union of male and female gametes.
Sexual Reproduction in Animals
Fertilization: Union of male (sperm) and female (egg) gametes to form zygote.
Types of Fertilization:
Internal Fertilization: Inside female (e.g., humans, cats).
External Fertilization: Outside female (e.g., fish, frogs).
Advantages and Disadvantages of Sexual Reproduction
Advantages:
Genetic variation.
Reduced chances of inheriting genetic diseases.
Continuous evolution.
Disadvantages:
Difficulty in finding a mate.
Risk of sexually transmitted diseases.
Energetically costly.