Growth and Development in Animals PDF

Growth and Development in Animals  What is Growth? Growth means getting bigger Animals grow throughout their lives Growth happens when cells: Get larger Make copies of themselves (cell division) Growth helps animals become stronger and bigge...

Growth and Development in Animals  What is Growth? Growth means getting bigger Animals grow throughout their lives Growth happens when cells: Get larger Make copies of themselves (cell division) Growth helps animals become stronger and bigger  Cell Growth and Division Cells are the building blocks of all living things As animals grow: Existing cells get bigger Cells divide to make new cells This process helps animals: Increase in size Replace old or damaged cells Heal injuries  What is Development? Development is how animals change as they grow Development includes: Changes in body shape New features appearing Learning new skills There are two main types of development: Direct development Indirect development  Direct Development Animals look like small versions of adults when born Example: Dogs Puppy development: Born with four legs, tail, and fur Gets bigger but keeps same basic shape Just grows larger and stronger  Indirect Development: Introduction Animals look very different from adults when born Must go through big changes to become adult Two types we'll learn about: Complete metamorphosis Incomplete metamorphosis  Complete Metamorphosis: Butterfly Four stages of life: Egg Caterpillar (larva) Chrysalis (pupa) Adult butterfly Each stage looks completely different Called complete metamorphosis  Incomplete Metamorphosis: Frog Three main stages: Egg Tadpole Adult frog Gradual changes occur Loses tail, grows legs Called incomplete metamorphosis  Comparing Types of Development Direct Development: Looks like mini adult Just gets bigger Example: Dog Indirect Development: Looks different from adult Goes through major changes Examples: Butterfly and frog  Review Time! Let's Remember: Growth means getting bigger through cell growth and division Development is how animals change as they grow Direct development: Animals look like small adults Indirect development: Animals change form completely Complete metamorphosis: Butterfly Incomplete metamorphosis: Frog