Understanding Reproduction

• Reproduction is a biological process where an organism creates biologically similar offspring.

Importance of Reproduction

• Procreation ensures the continuation of species.
• Quality improvement occurs through genetic variation.

Types of Reproduction

• Sexual Reproduction involves the fusion of two sex cells to form a zygote, usually requiring two parents and resulting in offspring with variations.
• Asexual Reproduction does not involve the fusion of sex cells and requires only one parent, producing genetically identical offspring or clones.

Sexual Reproduction Details

• Fusion of two sex cells creates a zygote.
• Two parents are usually needed.
• Offspring exhibit variations and are not identical to the parents.

Types of Cells

• Somatic or body cells include 22 pairs.
• Sex cells consist of one pair and include sperm and egg cells.
• Sexual reproduction in animals occurs in gametogenesis, spawning/mating, and fertilization.

Male and Female Reproductive Systems

• The male reproductive system produces and deposits sperm.
• The female reproductive system produces egg cells.
• Male reproductive organs produce sperm cells (spermatogenesis), are regulated by hormones, and vary across species.
• Female reproductive organs produce egg cells (oogenesis), undergo the ovarian and uterine cycle (menstrual cycle), and are regulated by hormones.

Sequential Hermaphroditism

• Species are born as one sex but can change into the other.
• Protogyny involves a change from female to male.
• Protandry involves a change from male to female.

Types of Fertilization

• External Fertilization happens outside the body, especially in aquatic animals.
• Internal Fertilization happens inside the body of the female, as in reptiles and mammals (including humans).

Animal Classification by Birth

• Oviparous animals deposit eggs in the external environment.
• Ovoviviparous animals retain eggs in their bodies, releasing young that can fend for themselves.
• Viviparous animals do not lay eggs; young develop inside the mother's body and are born independently.

Sexual Reproduction in Plants

• Flowering plants reproduce sexually through pollination.
• Pollination transfers pollen grains from the male anther to the female stigma.

Types of Pollination

• Self-pollination occurs when pollen moves from stamen to stigma of the same plant.
• Cross-pollination occurs when pollen moves to the stigma of another plant.

Asexual Reproduction

• Asexual Reproduction doesn't involve the fusion of sex cells.
• It requires only one parent.
• Offspring are clones, genetically identical to the parent.

Types of Asexual Reproduction

• Binary Fission involves the division of the body into two or more equal parts (e.g., bacteria, paramecium, amoeba).
• Budding involves a new organism developing as an outgrowth or bud from the parent body (e.g., hydra, yeast).
• Fragmentation involves the parent body breaking into pieces, each growing into a new individual (e.g., starfish, worms, fungi, lichen).
• Parthenogenesis involves unfertilized eggs developing into new offspring (e.g., bees, wasps, ants).

Vegetative Reproduction

• Vegetative Reproduction uses plant parts like roots, stems, and leaves to reproduce.

Types of Vegetative Reproduction

• Natural vegetative reproduction occurs through specialized reproductive structures.
• Artificial propagation is aided by humans.

Natural Vegetative Reproduction

• Natural vegetative reproduction uses vegetative parts or specialized reproductive structures.
• It primarily involves modified stems like runners, tubers, corms, and rhizomes.

Types of Natural Vegetative Reproduction

• Runners are new plants arising from nodes of above-ground horizontal stems.
• Strawberries use horizontal stems on the soil surface to reproduce.

Budding and Grafting

• Small stems attach to larger stems or roots of another plant.
• Examples include some fruits and nut trees.

Tissue Culture

• Tissue Culture involves placing pieces of tissue from one plant on a sterile medium to grow new individuals in mass numbers.

Genetically Identical Offspring

• Genetically identical offspring are produced by particular type of reproduction.

True or False directives

• Self-pollinating plants can fertilize themselves, while cross-pollinating plants need a vector to transfer pollen.
• Plants use physical characteristics to attract pollinators.
• Animals/insects that transfer pollen are called "pollinators."
• Fragmentation is not a type of asexual reproduction.
• Vegetative reproduction uses plant parts to reproduce.