What’s In a Life Cycle Do your parents have pictures of you when you were a baby If they do how do you look You probably look very different from the way you look now You have changed a lot since you were born and you will change in other ways as you grow and get older Life Changes All animals change over time They are born from their mother or hatch from an egg they grow and become adults then they get old and die This is a life cycle When animals become adults they are able to reproduce produce young When the offspring young are born they begin a new life cycle 쑼 The human life cycle Children are born and grow into adults who reproduce and have more children Adult Baby Child Teenager 4
Learning About Life Cycles In this book you will find out more about animal life cycles As you read you will learn secrets about how different animals are born grow reproduce and die Why do some animals change completely as they grow up Why are eggs so amazing And what happens to animals when they die 쑼 This little girl her mother and her grandmother are all at different stages of the human life cycle FAMILY CHANGES Look for photos of yourself when you were a baby How different do you look Would you recognize yourself if no one had told you who was in the photo See if you can find pictures of your parents and other family members when they were young Can you recognize them Why or why not 5
How Long Does a Life Cycle Last Some insects live only for a week Mice live for just a few years Humans whales and tortoises however can live for more than one hundred years Live Fast Die Young Animals that have short lives must cram everything into a short amount of time Mice are adults at around six weeks old and they produce their first young only three weeks later Other animals have even shorter lives The pygmy goby a small fish lives an average of only fifty-nine days Mayflies and some kinds of midge spend less than a day as adults 쑼 The maximum life spans of some different animals some were in zoos s r a e y 0 0 2 0 0 1 e a h w d a e h w o B l s r a e y 0 8 t n a h p e E l s r a e y 3 r e t s m a H s r a e y 6 2 g o D s r a e y 4 6 w a c a M s r a e y 6 2 y a j e u B l s r a e y 0 2 e k a n s r e t r a G s r a e y 0 5 n o e g r u t S s r a e y 5 5 l e E s r a e y 6 5 r o t a g i l l A s r a e y 0 0 1 l e s s u m r e t a w h s e r F s r a e y 8 2 t n A Mammals Birds Reptiles Fish Other 6
Slow and Steady Humans are among the longest-lived animals However we are not the record breakers Giant tortoises can live for more than 170 years They do not become adults until they are 20 or 25 Bowhead whales have been found with harpoon heads that are over 100 years old stuck in their skin Parrots 쑿 Giant tortoises such as this one from the Seychelles Islands can live for more than 100 years Some are said to approach 200 years in age and albatrosses are among the longest lived birds Albatrosses do not begin to reproduce until they are ten years old LONG LIVES Scientists have discovered ocean animals that live far longer than giant tortoises A clam caught off the coast of Iceland was found to be 405 years old Even more amazing there is a kind of sponge in the Antarctic that can live for more than 1,500 years 7
