Life Cycles

Join Bill Nye as he goes around and around and around to explain the cycle of life.

My, how you’ve grown! The popular exclamation from your Auntie may be no great revelation, but growing bigger is a part of life. In fact, it’s part of the whole cycle, or pattern, of human life that began with your birth. The different stages in life are called life cycles.

Humans aren’t the only ones with life cycles. At first, you might think that you have nothing in common with a cactus in the desert, or a fish in the sea, or the mold in your gym shoe, but you do. You’re all alive. You all have or will experience birth, growth, reproduction, aging, and eventually, death.

Growing up, raising a family, living and dying could be worse, or at least, different. You could be a housefly. A fly born on the same day as you were would have been dead before you were five days old.

Today is the first day of the rest of your life cycle!

The Big Idea

  • Living things are born, grow, reproduce, and die in regular patterns called life cycles.
  • Many living things regulate their life cycles with their own biological clocks.

Did You Know That?

  • With the shortest life cycle on Earth, adult mayflies don’t bother to eat?
  • Larger bodied animals tend to live longer lives and have slower reproductive rates than smaller animals?
  • A mother oyster may lay more than 10 million eggs during each year’s breeding season?

Books of Science!

  • “Hands-On Science: Things That Grow”by Megan StineGareth Stevens, 1993
  • “Biological Clocks”by Sarah R. RiedmanThomas Y. Crowell, 1982.