Reproduction either stamps identical copies or mixes two parents' traits — and that choice drives how much variation each generation gets.

Binary fission, budding, and spores all need only one parent and produce genetically identical offspring.

Cuttings, runners, tubers, bulbs, and aspen suckers make new plants without seeds — all clones of the parent.

Sperm and egg gametes join at fertilization to form a zygote, then cleavage builds an embryo that is not identical to either parent.

Pollen and ovules, pollination, pollen tubes, fertilization, and seeds that protect a dormant embryo with mixed traits.

Asexual is fast and cheap but fragile under change; sexual costs energy and makes fewer young but buys survival through variation.

Aphids, sponges, and many plants switch or combine asexual and sexual reproduction as conditions change.

Hermaphrodites can make both gametes; parthenogenesis turns unfertilized eggs into whole organisms, as in bee drones.