L 28.1 Levels of organisation

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L 28.1 Levels of Organization

* Learning Outcomes:

• Describe cell specialization and

levels of organization.

• Identify how levels of organization

work together in an organism.

STARTER: Pairs

Think about the way employees in a large company are organized. How would you describe the

relationship between different jobs,

divisions, and levels of responsibility in

a company?

Multicellular organisms are made up of cells, but different cells

in the organism have different functions. Take a moment to study the images

of the blood cells and nerve cells, or neurons.

How do you think these differences contributes to the cell's function? Discuss with your partner.

Cell specialization involves

two main steps: determination and differentiation. The cells produced during the first few divisions of the zygote are known as

embryonic stem cells. These cells have the potential to become any type of

specialized cell in the body.

Determination

It occurs in which most stem cells become committed to develop into only one type of cell. For instance, a stem cell might become a cardiac

muscle cell or a spinal neuron. These committed cells still retain all of the

genetic information needed to build an entire organism. However, during

determination, they lose their ability to express some of this information.

Once a cell is committed to becoming a specialized cell, it will develop into

only that type of cell.

Differentiation

Differentiation is the process by which committed cells acquire the structures

and functions of highly specialized cells. Differentiation occurs because

specific genes in each cell are turned on and off in a complex, regulated

pattern.

The different structures of these specialized cells, such as those shown

in FIGURE 1.2, allow them to perform specific functions within the body.

Task: In your group give one example of how specialization help cells perform a specific function.

https://www.youtube.com/watch?v=cyaVEotYsY0 (Incorporar)

Question: With your partner, answer the following question and upload your answer to the provided link.

How does the process of cell

determination differ from the

process of cell differentiation?

http://padlet.com/Reema_Albitar/3byv2cogz5pq

Cell specialization

Levels of Organization

Specialized, or differentiated, cells are only the first level of organization in a

multicellular organism. Scientists organize multicellular structures into five

basic levels, beginning with cells and moving to increasingly complex levels—

tissues, organs, organ systems, and the whole organism.

Refer to the flash cards below to identify each of the levels.

Levels of organisation

Search: {5 min.}

The human body, with its five levels of organization, can be compared to the

structure of an ecosystem with its different

levels of organisation. explore

this analogy.....use the internet. Provide a written explanation.

All levels of organization interact and work together to maintain the body’s health. (Fig. 1.3 pg. 801)

- Assessment:

Complete the questions in the class worksheet and upload to Showbie by the end of the session.