1. Unit 1 Lesson 4 Levels of Cellular Organization
Copyright © Houghton Mifflin Harcourt Publishing Company

2. Key Words Organism Organ Organ system Tissue Structure Function
Unit 1 Lesson 4 Levels of Cellular Organization
Key Words
Organism
Organ
Organ system
Tissue
Structure
Function
Copyright © Houghton Mifflin Harcourt Publishing Company 2

3. Body Building How are living things organized?
Unit 1 Lesson 4 Levels of Cellular Organization
Body Building
How are living things organized?
An organism is a living thing that can carry out life processes by itself.
Unicellular organisms are made up of just one cell that performs all the functions necessary for life.
Unicellular organisms do not have levels of organization.
Copyright © Houghton Mifflin Harcourt Publishing Company 3

4. How are living things organized?
Unit 1 Lesson 4 Levels of Cellular Organization
How are living things organized?
Unicellular organisms need fewer resources and some can live in harsh conditions.
They are very small and are easily eaten by other organisms.
If the single cell dies, the entire organism dies.
Copyright © Houghton Mifflin Harcourt Publishing Company 4

5. Unicellular Advantage/Disadvantage
Unit 1 Lesson 4 Levels of Cellular Organization
Unicellular Advantage/Disadvantage
Advantage
Disadvantage
Need fewer resources
Entire organism dies if the single cell dies
Can live in harsh conditions
Copyright © Houghton Mifflin Harcourt Publishing Company 5

6. How are living things organized?
Unit 1 Lesson 4 Levels of Cellular Organization
How are living things organized?
Multicellular organisms have multiple cells that are grouped into different levels of organization.
Multicellular organisms are larger, more efficient, and have a longer lifespan than unicellular organisms.
Multicellular organisms need more resources than unicellular organisms.
The cells are specialized and must depend on each other for survival of the organism.
Copyright © Houghton Mifflin Harcourt Publishing Company 6

7. Multicellular Advantage/Disadvantage
Unit 1 Lesson 4 Levels of Cellular Organization
Multicellular Advantage/Disadvantage
Advantage
Disadvantage
Larger size
Need more resources than unicellular
Cells Specialize to perform specific functions
Specialize cells mean that cells must depend on each other to perform all the functions than an organism needs to live
Longer Lifespan than unicellular organism
Copyright © Houghton Mifflin Harcourt Publishing Company 7

8. How are living things organized?
Unit 1 Lesson 4 Levels of Cellular Organization
How are living things organized?
A tissue is a group of similar cells that perform a common function.
For example: Muscles are made up of a groups muscle cells, all specialized to work hard. This group of muscles cells forms muscle tissue
Humans and other animals are made up of nervous, epithelial, connective, and muscle tissues.
Plants have transport, protective, and ground tissues.
Copyright © Houghton Mifflin Harcourt Publishing Company 8

9. Tissues become Organs Unit 1 Lesson 4 Levels of Cellular Organization
Copyright © Houghton Mifflin Harcourt Publishing Company 9

10. Tissues become Organs Animal Tissue Plant Tissue Both
Unit 1 Lesson 4 Levels of Cellular Organization
Tissues become Organs
Animal Tissue
Plant Tissue
Both
Copyright © Houghton Mifflin Harcourt Publishing Company 10

11. How are living things organized?
Unit 1 Lesson 4 Levels of Cellular Organization
How are living things organized?
An organ is a structure made up of a collection of tissues that carries out a specialized function.
Different tissues can work together to accomplish a function, such as digesting food.
Copyright © Houghton Mifflin Harcourt Publishing Company 11

12. How are living things organized?
Unit 1 Lesson 4 Levels of Cellular Organization
How are living things organized?
Example: Heart muscle is made up of
Fatty Tissue
Muscle Tissue
Nerve Tissue
Group 4
Copyright © Houghton Mifflin Harcourt Publishing Company 12

13. How are living things organized?
Unit 1 Lesson 4 Levels of Cellular Organization
How are living things organized?
Plants have organs such as leaves, stems, and roots.
Examples of human organs: heart, lungs, liver, brain
Copyright © Houghton Mifflin Harcourt Publishing Company 13

14. How are living things organized?
Unit 1 Lesson 4 Levels of Cellular Organization
How are living things organized?
An organ system is a group of organs that work together to perform body functions.
Each organ system in the body has a specific job to do for the organism.
Digestive System
Copyright © Houghton Mifflin Harcourt Publishing Company 14

15. Cells Tissue Organs Organ Systems How are living things organized?
Unit 1 Lesson 4 Levels of Cellular Organization
How are living things organized?
Cells
Tissue
Organs
Organ Systems
Copyright © Houghton Mifflin Harcourt Publishing Company 15

16. How are living things organized?
Unit 1 Lesson 4 Levels of Cellular Organization
How are living things organized?
What are the levels of organization in this tree?
Copyright © Houghton Mifflin Harcourt Publishing Company 16

17. Unit 1 Lesson 4 Levels of Cellular Organization
What’s Your Function?
What is the connection between structure and function?
Cells, tissues, organs, and organ systems make up the structure of a multicellular organism.
Structure is the arrangement of parts in an organism or object.
Function is the activity of each part in an organism.
Copyright © Houghton Mifflin Harcourt Publishing Company 17

18. What is the connection between structure and function?
Unit 1 Lesson 4 Levels of Cellular Organization
What is the connection between structure and function?
Tiny air sacs in the lung are called alveoli. What is the structure and function of alveoli?
Copyright © Houghton Mifflin Harcourt Publishing Company 18

19. Unit 1 Lesson 4 Levels of Cellular Organization
Odd Bodies
Different organisms develop many different kinds of body structures.
The spiny katydid has spines to protect it from being eaten.
Copyright © Houghton Mifflin Harcourt Publishing Company 19

20. Unit 1 Lesson 4 Levels of Cellular Organization
Odd Bodies
The longhorn cowfish has a puckered mouth to blow away sand on the shallow ocean floor to find and feed on tiny organisms.
The tarsier has huge eyes to give it better night vision for finding insects to eat. It also has long fingers to help it grasp branches.
Copyright © Houghton Mifflin Harcourt Publishing Company 20

21. Unit 1 Lesson 4 Levels of Cellular Organization
Systems at Work
What tasks do systems perform to meet the needs of cells?
A unicellular organism must perform all functions necessary for life.
A multicellular organism has specialized cells, tissues, organs, and organ systems that perform specific functions.
Some plants have a vascular system that transports water and nutrients to and from cells throughout the plant.
Group 2
Copyright © Houghton Mifflin Harcourt Publishing Company 21

22. What tasks do systems perform to meet the needs of cells?
Unit 1 Lesson 4 Levels of Cellular Organization
What tasks do systems perform to meet the needs of cells?
Food is broken down by the digestive system. Nutrients are delivered to cells via the circulatory system.
Oxygen is taken in by the respiratory system. This oxygen is carried to cells via the circulatory system.
Wastes are removed from the body by the skin, lungs, digestive system, and kidneys.
Copyright © Houghton Mifflin Harcourt Publishing Company 22