1. Slide 1 of 30 7-4 The Diversity of Cellular Life Copyright Pearson Prentice Hall The differences among living things arise from the ways in which cells are specialized to perform certain tasks and the ways in which cells associate with one another to form multicellular organisms.

2. Slide 2 of 30 Unicellular Organisms Copyright Pearson Prentice Hall Unicellular Organisms  Unicellular organisms are made up of only one cell.  Unicellular organisms dominate life on Earth.

3. Slide 3 of 30 Multicellular Organisms Copyright Pearson Prentice Hall Multicellular Organisms Multicellular  Organisms that are made up of many cells are called multicellular.  There is a great variety among multicellular organisms.

4. Slide 4 of 30 Multicellular Organisms Copyright Pearson Prentice Hall  What is cell specialization?

5. Slide 5 of 30 Multicellular Organisms Copyright Pearson Prentice Hall  Cells throughout an organism can develop in different ways to perform different tasks.  This process is called cell specialization.

6. Slide 6 of 30 Multicellular Organisms Copyright Pearson Prentice Hall  Specialized Animal Cells  Animal cells are specialized in many ways.

7. Slide 7 of 30 Multicellular Organisms Copyright Pearson Prentice Hall  Specialized Plant Cells  Plants exchange carbon dioxide, oxygen, water vapor, and other gases through tiny openings called stomata on the undersides of leaves.  Highly specialized cells, known as guard cells, regulate this exchange.

8. Slide 8 of 30 Levels of Organization Copyright Pearson Prentice Hall  What are the four levels of organization in multicellular organisms?

9. Slide 9 of 30 Levels of Organization Copyright Pearson Prentice Hall Levels of Organization  The levels of organization in a multicellular organism are:  individual cells  tissues  organs  organ systems

10. Slide 10 of 30 Levels of Organization Copyright Pearson Prentice Hall Levels of Organization Smooth muscle tissue Muscle cell Stomach Digestive system

11. Slide 11 of 30 Levels of Organization Copyright Pearson Prentice Hall In multicellular organisms, cells are the first level of organization.

12. Slide 12 of 30 Levels of Organization Copyright Pearson Prentice Hall  Tissues  Similar cells are grouped into units called tissues.  A tissue is a group of similar cells that perform a particular function.

13. Slide 13 of 30 Levels of Organization Copyright Pearson Prentice Hall Most animals have four main types of tissue:  muscle  epithelial  nervous  connective

14. Slide 14 of 30 Levels of Organization Copyright Pearson Prentice Hall  Organs  Organs are groups of tissues that work together to perform a specific function.

15. Slide 15 of 30 Levels of Organization Copyright Pearson Prentice Hall  Organ Systems  In most cases, an organ completes a series of specialized tasks.  A group of organs that work together to perform a specific function is called an organ system.

16. Slide 16 of 30 7-4 Copyright Pearson Prentice Hall  Cell specialization is characteristic of  bacteria.  all unicellular organisms.  yeasts.  multicellular organisms.

17. Slide 17 of 30 7-4 Copyright Pearson Prentice Hall  Which of the following cells is specialized for contraction?  muscle cell  red blood cell  pancreatic cell  nerve cell

18. Slide 18 of 30 7-4 Copyright Pearson Prentice Hall  The stomach is an example of a(an)  tissue.  organ.  organ system.  organism.

19. Slide 19 of 30 7-4 Copyright Pearson Prentice Hall  Which of the following shows the levels of organization in an organism from the simplest to the most complex?  organ system, organ, cell, tissue  tissue, cell, organ, organ system  cell, tissue, organ, organ system  cell, organ, tissue, organ system

20. Slide 20 of 30 7-4 Copyright Pearson Prentice Hall  Which of the following would probably contain the greatest variety of specialized cells?  an organ system  a tissue  an organ  a multicellular organism