A life cycle is the series of stages a living thing goes through from birth to adulthood to producing the next generation. Every living thing — plants, animals, and even tiny organisms — has a life cycle. Life cycles repeat across generations, which is why they are drawn as circles.
Compare life cycle diagrams of several living things side by side: a plant, a butterfly, a chicken, and a human. Point out that they all start somewhere, grow, become adults, and produce the next generation. Discuss what is the same and what is different.
You have already learned about plant life cycles and animal life cycles separately. Now let's zoom out and see the big picture: every living thing on Earth has a life cycle, and they all follow the same basic pattern.
A life cycle is the series of stages a living thing goes through during its life. It always includes the same basic steps: the organism starts life (by being born, hatching from an egg, or sprouting from a seed), it grows and develops (getting bigger and gaining new abilities), it reaches adulthood (when it is fully grown), and it reproduces (makes offspring — babies, eggs, or seeds). Those offspring then go through the same stages, and the cycle continues.
The key word is cycle — it goes around in a circle. A chicken hatches from an egg, grows into a hen, lays eggs, and those eggs hatch into new chicks. A bean sprouts from a seed, grows into a plant, makes flowers and seeds, and those seeds sprout into new plants. The individual animal or plant eventually dies, but the cycle keeps going because it passed life on to the next generation.
Different living things have life cycles that look very different on the surface. A butterfly goes through four dramatic stages (egg, caterpillar, chrysalis, butterfly). A human grows gradually from baby to child to teenager to adult. A dandelion goes from seed to plant to flower to puffball of seeds. But underneath the differences, the same pattern is always there: begin, grow, mature, reproduce, and begin again.
Understanding life cycles helps you see how life keeps going on Earth. No individual lives forever, but through reproduction, life has continued unbroken for billions of years. Every living thing you see today is the latest round in a life cycle that stretches back countless generations.