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NAME: ________________________________________________ PERIOD: ________
UNIT 3 PART 4 WORKSHEET
1. A newly formed organism just starting to develop is called an ________________________________.
2. Development involves ______________________________, ________________________________,
and _____________________________________________________.
3. Cleavage is _________________________________________________________________________.
4. As the embryo develops it forms a solid ball of cells called a __________________________________.
eventually this forms a hollow ball called a _____________________________________ and the
space inside is called the ____________________________________. When one side pushes in a
______________________________ is formed. Once a third layer of cells starts to grow there are
now three ______________________________________________________________________.
5. When cells change to become specific types of cells it is called ________________________________.
These cells then form different organs. If they all start out the same, how do they end up different?
_______________________________________________________________________________
6. Fill in the blanks with ectoderm, endoderm, or mesoderm.
______________________________
forms the nervous system
______________________________
forms bones
______________________________
the outside layer
______________________________
forms the lining of the stomach
______________________________
the middle layer
______________________________
forms the lungs
______________________________
forms the skin
______________________________
the inside layer