   |
||||||||||
|
||||||||||
TIPS:
Targeted Interventions for Proficiency in Science |
||||||||||
|
||||||||||
Life Science
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Students know cells combine to form tissues that combine to form organs and organ systems that are specialized to perform life functions. E/S The smallest unit of life is a single cell. A single-celled organism must perform all of the functions of life independently of other cells. In contrast, multicellular organisms have differentiated cells that perform specific tasks that collectively perform all of the functions of life.
Levels of Organization One type of cells working together to perform a specific function is called a tissue. Examples of tissue are muscle (Figure 3), nerve (Figure 4), epithelial (Figure 5), and connective tissues. These tissues are made of many cells performing a function together. Muscle tissues have the ability to contract and relax performing movement, nerve tissue responds to stimuli and conducts impulses, epithelial cells provide a continuous protective barrier between the body and the environment, and connective tissue supports and binds other tissues.
The heart is an example of an organ. It is made up of several types of tissues like muscle, nerve, and connective tissues working together to move blood around the body.
Figure 6. The heart. The next level of hierarchy is the organ system. An organ system is composed of several organs working together to perform a specific function. The heart is part of the circulatory system which heart works together with the veins, arteries, blood, and capillaries to transport oxygen and nutrients to all of the cells in an organism and carry away metabolic wastes.
Figure 7. The human circulatory
system. Finally, several organ systems working collectively comprise the whole organism. Each system depends on the others to complete the activities of life. For example, the circulatory system is responsible for delivery of materials, including oxygen, around the body. Therefore, the circulatory system is linked with the respiratory system which absorbs oxygen from the air and transfers it to the bloodstream.
Figure 8. The whole human body. To review, multicellular organisms have multiple levels of organization. An organism is made up of several organ systems. Each organ system is made up of several organs that work together. Each organ is made up of several tissues working together. Finally, each tissue is made up of similar cells working together. Figure 9 illustrates this hierarchy within a frog starting with a muscle cell. This muscle cell works with other muscle cells to form smooth muscle tissue. The muscle tissue works with other tissues to form a heart which combines with other organs to form the circulatory system. Finally, the respiratory system works with other organ systems to form the frog.
Human Organ Systems The following table summaries the structure and function of the major organ systems of the human body.
For further detail on organ systems visit MS TIPS Benchmark L.8.B.2 Content Benchmark L.8.B.4 Students know cells combine to form tissues that combine to form organs and organ systems that are specialized to perform life functions. E/S
Students confuse digestion with cellular respiration. It is difficult for students to understand that digestion is only the breakdown of food, both mechanically and chemically, into absorbable substances necessary for growth and maintenance. Digestion begins in the mouth with chewing and the enzyme activity of saliva. Acid and different enzymes in the stomach continue the breakdown of macromolecules. The majority of digestion and absorption actually takes place in the small intestine. Nutrients pass through the wall of the small intestine and enter the blood stream. The large intestine absorbs water and stores feces for elimination from the body. Carbohydrates in the bloodstream are broken down into glucose and delivered to every cell in the body. Energy is derived from the glucose at the cellular level through the process of respiration. For more information on digestion visit
Breathing refers to the process that brings about an exchange of gases between the organism and its environment. Respiratory tissue absorbs oxygen and expels carbon dioxide. On the other hand, respiration refers to the process that releases energy from food substances in living cells. At the primary level, students do not make the distinction between breathing as a physical process and respiration as a chemical process. For further explanation of this misconception visit
Students usually learn the body systems in isolation and memorize the parts and function of each organ, but lack understanding of how the systems work together. For example, the circulatory system functions to transports materials to body cells and remove metabolic wastes. These transported materials may have origins in the respiratory system (oxygen, carbon dioxide), endocrine system (hormones), digestive system (nutrients), immune system (white blood cells), and the excretory system (metabolic wastes). For information on how the body systems interact with the nervous
system visit http://faculty.washington.edu/chudler/organ.html
“Skeletal muscles are probably most familiar to middle school students even though other types of muscles, cardiac and smooth, are essential for life functions. The heart muscle is composed of a different type of muscle cell (cardiac muscle cells) and beats to move blood throughout the body. Smooth muscle cells line blood vessels and the intestinal tract to help move blood or food through those passages. The tongue is made up of muscle cells that enable us to speak and is also an important part of the digestive system.” An article on misconceptions associated with the muscular system
can be found at
Students believe that if they stop exercising their muscles will turn into fat. Students must understand that muscle cells cannot change into adipose (fat) cells and understand the definition of a tissue. Cells are differentiated. This means that cells may differ from one another in structure and function but they retain that same function through out the life of the cell. Muscles cells and fat cells may increase or decrease in volume or quantity due to changes in nutrition and activity, but the cells do not convert from one form to another. The following link provides and explanation of different types of human body cells http://www.cancerhelp.org.uk/help/default.asp?page=98
Students can easily identify roots, stems, and leaves in a plant
but do not understand that plants are also made of cells organized
into tissues, organs, and organ systems. For example, vascular plants
have a circulatory system composed of xylem (transports water from
the roots to the leaves) and phloem (transports sugars from the
leaves to the rest of the plant) tissues that work together to circulate
materials around a plant. Xylem is made up of two main types of
cells: tracheids and vessel elements. Xylem also contains other
kinds of cells, such as parenchyma, that function in structure and
storage. Phloem is made up of sieve tube cells and companion cells,
as well as parenchyma cells. Therefore, together xylem and phloem
comprise the circulatory system of a vascular plant. Content Benchmark L.8.B.4 Students know cells combine to form tissues that combine to form organs and organ systems that are specialized to perform life functions. E/S 1st Item Specification: Know cells work together to form tissues, organs, and organ systems. Depth of Knowledge Level 1
Depth of Knowledge Level 2
Which of the following best describes the level of organization in the diagram above?
2nd Item Specification: Know the functions of organs and organ systems. (i.e. skeletal, muscular, digestive, circulatory, respiratory, nervous) Depth of Knowledge Level 1
Depth of Knowledge Level 2
3rd Item Specification: Know there are different types of cells within tissues, organs, and organ systems in the same organism designed to take on specialized tasks. Depth of Knowledge Level 1
Depth of Knowledge Level 2
Constructed Response L.8.B.4 1. Answer the following questions regarding the human circulatory system.
Content Benchmark L.8.B.4 Students know cells combine to form tissues that combine to form organs and organ systems that are specialized to perform life functions. E/S Answer to Sample Test Questions
Constructed Response L.8.B.4 Score Rubric:
Content Benchmark L.8.B.4 Students know cells combine to form tissues that combine to form organs and organ systems that are specialized to perform life functions. E/S Intervention Strategies and Resources The following is a list of intervention strategies and resources
that will facilitate student understanding of this benchmark. 1.Online research/writing activity This lesson asks students to “use the internet and library resources to find out more about the effects of zero gravity and space travel on body systems. Then create a brochure that explains some of the technologies that allow people to live for extended periods of time in space. This is a good chance to have students write. They need to express an understanding of organ systems and explain the effects that space travel would have on those systems. The hook for this activity is students’ natural curiosity of space. You can access this activity at http://go.hrw.com/resources/go_sc/hst/ia/hstl22.htm
“This practice lesson introduces students to several organ systems through an interactive online experience. The objective of the lesson is for students to understand that there are different systems within the body and that they work independently and together to form a functioning human body. Through the use of an online interactive activity, students learn about the concept of separate components working together to build a body system. In addition, this lesson focuses on activities to help students learn that body systems work together to build the functioning human body. This lesson could be used in conjunction with instruction on the human body and/or systems.” http://ohiorc.org/record/3572.aspx You can access the lesson plan page through the following link
Nothing motivates a middle school student more than an explanation of belches, snot, and ear wax. This website lets students “find out all about the human body with Wendell the Worm, Yucky's Ace Reporter.” The website allows students to choose a body function or a body system to investigate. The reading level is appropriate for middle school students and the explanations are grounded in science. You can access this site at http://yucky.discovery.com/flash/body/index.html 4.Neuroscience for Kids “Discover the exciting world of the brain, spinal cord, neurons, and the senses. Use the experiments activities and games to help you learn about the nervous system. There are plenty of links to other web sites for you to explore.” This is a great website written for middle aged students to investigate the nervous system. Parts of the website are available in Spanish and other languages. You can access this website at http://faculty.washington.edu/chudler/neurok.html
“This "Organ Systems" module has five units of instruction that focus on the main classes of functions that a body must perform. Rather than just naming organs of the body and what they do, we present a perspective on the body as a coordinated group of systems that must do certain things correctly in order to survive and thrive.” This is a great website for average to above average middle school students. It has five modules including: Bodily Defenses, Digestion, Detoxification, Gas Exchange, and Coordination and Control. Each module starts with an introduction with module objectives. Then each module covers why each system is important, how we learned about each system’s structure and function, historical perspective, and common hazards. Each module also contains several activities that teachers can use to reinforce the concepts presented. Lastly, each module contains a “Self-Study Game”. A plug-in must be downloaded to run the Self-Study Game. There is also a teacher companion site. An account must be activated to use the teacher pages. You can access this website at |
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
