Name __________________ Date______________Unit 2: Characteristics of Living Things

Lesson 19: Homeostasis

Vocabulary Words of the Day: Homeostasis, Cell Membrane (review)Why It Matters: AlllivingthingsonEartharetiedtogether bycommon traitsandrelyonhomeostasis fortheirsurvival.

Objective: Students will be able to identify the state of homeostasis and explain its significance to survival.Essential Questions: 1. What is homeostasis?

2. How is homeostasis significant for an organisms survival?3. How does the cell membrane help a cell maintain homeostasis?

Do Now

a. Lifting a book from a bookshelf. b. Coordinating the functions of organelles.c. Digesting food in the small intestine.d. Carrying out the process of protein synthesis.

1. Two types of human cells are shown in the diagram to the right. Cell A causes the cells at B to contract. This activity would be most useful for:

HOMEOSTASIS1. All living things respond to their environment. These reactions help our bodies maintain

homeostasis.2. Individual cells, as well as organisms, must maintain homeostasis in order to live. 3. One way that a cell maintains homeostasis is by controlling the movement of substances across

the cell membrane.

Ø Question:Whatishomeostasis?

Ø QuestionReview: Whataresome rolesofthecellmembrane?

4. Thesefunctionscontributetomaintaining homeostasis.

ü Answer: Homeostasis is the maintenance of stable internal conditions in a changing environment.

ü Answer: The cell membrane acts as a gatekeeper, by allowing some materials but not others to enter the cell. It provides structural support to the cytoplasm, recognizes foreign material, and communicates with other cells.

Balanced Unbalanced

MODEL

Suzie & Eric are both maintaining homeostasis!MODEL

This plant is -> maintaining homeostasis!

Plant #1 Plant #2

Which plant is maintaining homeostasis?Guided Practice

CARLCompare the images and relate it to the concept of homeostasis.Damion

Hypothesize what could happen to Carl if his homeostasis continues to be threatened.

Turn & Talk

Who in this picture is not maintaining homeostasis?

How do we know?

Isthisownerhelpinghisdogmaintainhomeostasis?

If yes, explain.

If no, why not?

Analyzethispicture.Arewemaintaininghomeostasiswhenwearestressed?

Stress happens when internal homeostasis is threatened.

Team Talk

“The Thirsty Crow”Directions: As you read “The Thirsty Crow,” underline or highlight evidence of homeostasis AND non-homeostasis. Be prepared for a group discussion about your text evidence.

Independent Practice

1. How do you know when you are in a state of homeostasis?2. Explain why organisms need homeostasis to survive.

Assessyourlearning:ExitTicket

Create your own scenario of a person or animal whose homeostasis is being threatened. Explain how the organism was able to return to homeostasis.

Due: 10/19