MS-LS1-3: Arguing That the Body Is a System of Interacting Subsystems
In plain English: MS-LS1-3 is the NGSS middle school performance expectation that asks students to argue from evidence that the body is a system of interacting subsystems made of groups of cells. Students trace how cells form tissues, organs and organ systems, and use data to show systems such as the respiratory, circulatory and muscular systems working together. It is usually taught in grade 6, 7 or 8 life science.
Use argument supported by evidence for how the body is a system of interacting subsystems composed of groups of cells.
Clarification Statement: Emphasis is on the conceptual understanding that cells form tissues and tissues form organs specialized for particular body functions. Examples could include the interaction of subsystems within a system and the normal functioning of those systems.
Assessment Boundary: Assessment does not include the mechanism of one body system independent of others. Assessment is limited to the circulatory, excretory, digestive, respiratory, muscular, and nervous systems.
Next Generation Science Standards · Disciplinary Core Idea: From Molecules to Organisms: Structures and Processes · Official standard
Students build and defend an argument that the human body is a system of interacting subsystems made of groups of cells. They start with the levels: cells of one kind group into a tissue, several tissues work together in an organ, and organs work together in an organ system. Then they collect and analyze evidence that the systems depend on each other: a clothespin muscle test, a paper towel model of the lining of the small intestine, and station cards with data about breathing, digestion, wastes and nerve signals. Every task ends in a claim backed by evidence and reasoning.
The NGSS Clarification Statement says: "Emphasis is on the conceptual understanding that cells form tissues and tissues form organs specialized for particular body functions. Examples could include the interaction of subsystems within a system and the normal functioning of those systems." The Assessment Boundary says: "Assessment does not include the mechanism of one body system independent of others. Assessment is limited to the circulatory, excretory, digestive, respiratory, muscular, and nervous systems." So every activity, homework and quiz item on this page is about how two or more of these six systems work together, never about how one system works on its own. Other systems, such as the skeletal and immune systems, are beyond this standard and are not assessed. Class data on this page are invented for teaching and labeled as invented; body values marked as rounded are typical published values for healthy people.
Learning Objectives
By the end of this lesson, students will be able to:
Describe how cells form tissues, tissues form organs, and organs form organ systems
Give examples of the circulatory, respiratory, digestive, excretory, muscular and nervous systems interacting
Analyze data from a body investigation and from cases to find evidence that systems depend on each other
Explain the normal functioning of body systems working together during everyday activities
Write and critique arguments with a claim, evidence and reasoning
Prior Knowledge Required
Students should already be comfortable with:
Living things are made of one cell or many cells MS-LS1-1
The parts of a cell work together so the whole cell can live MS-LS1-2
Finding a percent of a quantity and a percent change 6.RP.A.3
Ask students to sit still for 15 seconds and notice everything their body is doing without being told (breathing, heartbeat, blinking, digesting breakfast). Then ask:
Warm-Up Prompt
"Your leg muscles need food and oxygen to keep working during a soccer game. Draw arrows to show where the food and the oxygen come from and how they reach the muscle. How many body systems did you need?"
Share a few drawings. Most will show the lungs, the stomach, the heart and the muscle. Ask what tells the muscle when to move: that adds the nervous system. Keep the drawings for Closure.
Direct Instruction15 minutes
From cells to systems. A tissue is a group of similar cells that do one job together. An organ is a body part made of two or more kinds of tissue working together, such as the heart or a lung. An organ system is a group of organs that work together for a major job. A subsystem is a smaller system that is part of a bigger one: each organ system is a subsystem of the whole body. This lesson uses six systems: circulatory (heart, blood vessels and blood carry materials), respiratory (lungs take in oxygen and give off carbon dioxide, a waste gas that cells make), digestive (breaks food into materials the blood can carry), excretory (kidneys remove wastes from the blood), muscular (muscles move the body) and nervous (brain and nerves send signals). Show Diagram 1, then work through the examples.
Levels of organization: the small intestine
Build the levels for the organ where most digested food enters the blood.
Result: Cells: lining cells that take in food materials, and smooth muscle cells. Tissues: the lining tissue, muscle tissue that squeezes food along, and nerve tissue. Organ: the small intestine, made of all three. System: the digestive system, with the stomach and other organs.
Official example: subsystems interacting on a bike ride
A student's breathing rises from 15 breaths per minute at rest to 33 breaths per minute while riding uphill (invented data). Her pulse (the number of heartbeats per minute) rises too.
Result: 33 ÷ 15 = 2.2, so she breathes 2.2 times as fast. Leg muscle cells (muscular) need more oxygen, the lungs (respiratory) take in more, the heart (circulatory) pumps the oxygen-rich blood faster, and the brain (nervous) sends the signals that speed up breathing and move the legs.
Official example: the normal functioning of the systems after lunch
Trace a sandwich from lunch to a working arm muscle that afternoon.
Result: Digestive: the stomach and small intestine break the food down. Circulatory: blood picks up the food materials in the small intestine and carries them to every cell. Respiratory: oxygen enters the blood in the lungs. Muscular: arm muscle cells use the food and oxygen to move. Excretory: kidneys remove the wastes the cells release into the blood.
Rounded real values: kidneys and blood
Each day an adult's kidneys filter about 180 L of fluid out of the blood but make only about 1.5 L of urine.
Result: 180 - 1.5 = 178.5 L goes back into the blood, so 178.5 ÷ 180 ≈ 99% is returned. The excretory system depends on the circulatory system to bring it blood, and it keeps the blood clean for every other system.
When one link fails: an asthma attack
During an asthma attack, muscle tissue around the airways in the lungs tightens and the airways narrow.
Result: Less air reaches the lungs, so less oxygen enters the blood. The brain signals faster breathing and a faster pulse, and leg muscles tire quickly. A problem in one system shows up in others, which is evidence that they interact.
After each example ask: "Which systems are involved, and what is passed from one to the next?" Model the argument structure the class will use all lesson: claim (the answer), evidence (data or observations) and reasoning (why the evidence supports the claim).
Guided Practice15 minutes
Pairs analyze invented breathing data for one 13-year-old at four moments of a normal school day and build an argument together.
Guided practice data (invented): breathing rate during one day
Moment
Activity
Breaths per minute
1
Sleeping (6:00 a.m.)
12
2
Sitting in class
16
3
Walking to lunch
22
4
Playing soccer at recess
36
Find how many times as fast the student breathes during soccer as during sleep (36 ÷ 12 = 3).
For moment 4, list every system that is working harder than during sleep, and what each one passes to another.
Write a claim: "During soccer, the respiratory, circulatory, muscular and nervous systems interact to ___."
Add the evidence (two numbers from the table) and the reasoning (why muscle cells need more from the other systems).
Independent Practice10 minutes
Each student writes a claim, evidence and reasoning paragraph from new invented data. A 14-year-old trains for a 5 km race for 12 weeks. Her resting pulse is 78 beats per minute at week 0, 74 at week 4, 70 at week 8 and 67 at week 12. Students find the drop (11 beats per minute, about 14%) and argue how the heart's muscle tissue, the circulatory system and the body's muscle cells are connected: a stronger heart pushes more blood with each beat, so fewer beats can deliver the oxygen and food her resting muscle cells need.
Closure5 minutes
Students return to their warm-up drawings and add labels: the system each organ belongs to, one tissue in each organ, and the cells at the end of every arrow. Exit ticket: "Name two systems that must work together for you to climb a flight of stairs, and one thing that passes between them."
Differentiation Strategies
For Struggling Students
Give a system card set (organ pictures sorted by system) and a "passes to" arrow card for each pair of systems
Provide a claim-evidence-reasoning frame with blanks for two numbers from the data
Let students write arguments about two systems before adding a third
For Advanced Students
Ask students to design a fair test of the clothespin investigation with more students, and to predict how the results would change
Have students build a web that shows all six systems, with one arrow for each thing passed between two systems, and defend each arrow with evidence
Ask students to find a weakness in one of the station cards (sample size, missing comparison) and say what data would make the argument stronger
Assessment Guidance
What to Look For
Check that every argument names at least two systems and what passes between them (oxygen, food materials, wastes, signals), rather than listing systems one at a time. Look for the levels in the right order and for organs described as made of more than one tissue. Watch for students who use a single number as evidence without comparing it with anything, and for arguments about one system alone, which this standard does not ask for. Check percent and rate calculations for the right starting value.
02
Classroom Activities
3 Activities
1
Clothespin Squeeze Test
20 minPairs
One partner squeezes a wooden clothespin between thumb and index finger as many times as possible in 30 seconds while the other counts and times. They run five trials in a row with no rest, once with the arm hanging at the side and, after a 10-minute rest, once with the arm raised straight above the head.
Procedure
Use the same hand, the same clothespin and the same counting rule (the jaws must touch) for both arm positions.
Record the count for each 30-second trial. Switch the order (raised first or hanging first) for half the pairs, so tiredness from the first test does not decide the result.
Pool the class data for each arm position and graph the means.
Safety: never squeeze skin with the clothespin, stop if anything hurts, and any student with a hand or arm injury acts as the timer instead.
Sample Data (invented)
One student, squeezes in five 30-second trials. Arm at side: 58, 55, 53, 51, 50. Arm raised: 57, 48, 41, 36, 32. Diagram 2 graphs these data.
Discussion Questions
Both tests started near the same count. Find the percent drop from trial 1 to trial 5 for each arm position. Which one dropped more?
Compare where the hand is, relative to the heart, in the two positions. Use that to explain the difference, naming the circulatory and muscular systems.
Which system tells the finger muscles when to squeeze, and which system lets you feel the burning in your forearm?
One student is a small sample. What would make the class argument stronger?
Modification for Distance Learning
Students run the test at home with any spring clothespin or a sponge squeezed into a cup, share their counts in a class spreadsheet, and post a short argument with the class means.
2
Folded Towel Model of the Small Intestine
20 minGroups of 3
The inner lining of the small intestine is covered with villi: tiny finger-like folds, each holding very small blood vessels called capillaries. Groups model why the folds matter by comparing a flat paper towel strip with a folded one that fits into the same length.
Procedure
Strip A: a flat paper towel strip 20 cm long and 10 cm wide. Strip B: a strip 60 cm long and 10 cm wide, folded back and forth like a fan until it is 20 cm long. (The teacher pre-cuts the strips.)
Pour 100 mL of water into a tray. Lay strip A in it for 10 seconds, lift it, let it drip for 5 seconds over the tray, and set it aside. Measure the water left.
Refill the tray to 100 mL and repeat with strip B.
Safety: wipe up spills at once so nobody slips.
Sample Data (invented)
Water left in the tray: 92 mL after strip A and 76 mL after strip B. Both strips take up the same 20 cm of tray.
Discussion Questions
How much water did each strip take up? How many times as much did the folded strip take up, and how does that compare with the amount of towel in it?
In the body, food materials pass from the small intestine into the capillaries. Which two systems does this connect?
Once the food materials are in the blood, how do they reach a muscle cell in your leg?
Name one way the towel model is not like a real intestine.
Challenge Variation
Groups predict, then test, how much water a 100 cm strip folded to 20 cm takes up, and explain whether the pattern holds.
3
Argument Stations: Which Systems Are Talking?
25 minGroups of 3-4
Four stations each hold an evidence card. At each one, groups name the systems involved, write one claim with evidence and reasoning on a sticky note, and post it on the station's chart. Groups rotate every 6 minutes and may add a comment to another group's note.
Station Cards
Station 1, stomach after a meal (rounded real value): the muscle tissue in the stomach wall contracts about 3 times per minute to churn food, and nerves in the stomach wall help control these contractions. How many contractions in 20 minutes?
Station 2, the air you breathe (rounded real values): air breathed in is about 0.04% carbon dioxide; air breathed out is about 4%. The carbon dioxide comes from body cells and travels in the blood to the lungs.
Station 3, breathing muscle: a sheet of muscle under the lungs, the diaphragm, contracts each time you breathe in. It contracts only when a nerve from the spinal cord signals it.
Station 4, a long flight (invented data): a passenger's ankle measures 23.0 cm around before a 6-hour flight and 23.6 cm after sitting still the whole way. On the return flight she walks the aisle every hour, and her ankle grows only to 23.2 cm. Leg muscles squeeze the veins as they contract, which helps push blood back up to the heart.
Discussion Questions
At which station do three systems interact? Name them and what passes between them.
At Station 2, how many times more carbon dioxide is in the air you breathe out? What does that show about the respiratory and circulatory systems?
At Station 4, the walking flight had less swelling. What evidence would you add to make that argument stronger?
Modification for Distance Learning
Post each station card on its own slide. Groups add their claim, evidence and reasoning to the slide and reply to one other group's argument.
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: From Heart Muscle Cells to Interacting Systems
Heart muscle cells group into heart muscle tissue; that tissue, nerve tissue and lining tissue form the heart, an organ; the heart, blood vessels and blood form the circulatory system. The dashed lines show three systems the circulatory system interacts with all the time.
Diagram 2: Clothespin Squeeze Test (Invented Data)
Squeezes per 30-second trial for one student, five trials in a row with no rest, drawn to scale from the invented sample data in Activity 1. The solid line is the arm hanging at the side and the dashed line is the arm raised above the head.
04
Homework Assignment
~30 min
MS-LS1-3 Homework: Arguing with Evidence About Body Systems
Directions: Data marked invented are made up for practice; values marked rounded are typical values for healthy people. Use only the circulatory, respiratory, digestive, excretory, muscular and nervous systems. Show your math, and end each argument with a claim, evidence and reasoning.
Part 1: Cells to Systems (Problems 1-2)
Sort these into cell, tissue, organ or organ system: a nerve cell; the brain; the nervous system; a layer of lining cells in the lungs; a lung; the respiratory system. (a) Write two chains from smallest to largest. (b) The brain contains nerve tissue and tissue that carries blood. Why does that make the brain an organ rather than a tissue? (c) Name the system that supplies the brain's cells with oxygen, and the system that delivers it.
Invented data for one student over four days. Water drunk: 1.5, 2.0, 2.5, 3.0 L. Urine made: 0.9, 1.3, 1.8, 2.2 L. (a) For each day, find the water lost in other ways, such as water vapor in breath. (b) From day 1 to day 4, how much did water drunk and urine made each increase? (c) Use the digestive, circulatory and excretory systems to explain how extra water in a drink ends up as extra urine.
Part 2: Interactions as Evidence (Problems 3-4)
Invented data for a hiker resting at four elevations. Sea level: 14 breaths and 66 beats per minute. 1,500 m: 15 breaths and 70 beats. 3,000 m: 18 breaths and 78 beats. 4,000 m: 21 breaths and 86 beats. (High up, each breath holds less oxygen.) (a) Find the percent increase from sea level to 4,000 m for breathing and for pulse. (b) Write an argument that the respiratory and circulatory systems work together to keep the hiker's cells supplied with oxygen.
Sam claims, "The digestive system works on its own. It breaks down food without help from any other system." Use these facts to write a rebuttal: the stomach wall contains muscle tissue whose contractions are controlled in part by nerves; food materials pass into the blood through the lining of the small intestine; the cells of the stomach and intestine need oxygen brought by the blood. Name at least three systems.
Part 3: Normal Function and Broken Links (Problems 5-6)
Invented data for a student with food poisoning who cannot keep water down for a day. Urine: 1.4 L on a normal day, 0.5 L on the sick day. Resting pulse: 68 beats per minute on a normal day, 88 on the sick day. (a) Find the percent change in each. (b) Explain the changes using the digestive, circulatory and excretory systems: where did the missing water go, and why might the heart beat faster when the blood holds less water?
Write a full argument for the claim "The body is a system of interacting subsystems made of groups of cells." Use (a) the levels from cell to organ system for one organ of your choice, (b) one data set from this lesson or this homework as evidence of two systems interacting, and (c) reasoning that explains why a problem in one system affects the others.
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
Levels of Organization
Cells, tissues, organs and systems in the right order, with organs made of more than one tissue
Levels named but one is out of order or an organ is called a tissue
Data and Calculations
Differences, rates and percents correct, with units
Correct method with one arithmetic or unit error
Systems Interacting
Names at least two systems and what passes between them in every argument
Names systems but describes them one at a time
Claim, Evidence, Reasoning
Claim answers the question, evidence uses numbers or observations, reasoning links them
Claim and evidence given, reasoning missing or general
05
Quiz: 20 Questions
Interactive, with answers
Instructions
Data marked invented are made up for practice, and values marked rounded are typical values for healthy people. Every question uses the circulatory, respiratory, digestive, excretory, muscular and nervous systems. Your score updates as you answer, and Reset quiz clears everything so you or your students can try again.
Multiple choice: pick an option to check it. Short answer: write your answer, then reveal the model answer.
0 of 20 answered · 0 correct
Question 1 of 20 · Multiple Choice
Which list goes from the largest level of organization to the smallest?
Answer: B
The nervous system includes the brain, the brain is an organ made partly of nerve tissue, and nerve tissue is made of nerve cells. Choice A is the right order but from smallest to largest. Choice C puts the brain above the whole system it belongs to.
Question 2 of 20 · Multiple Choice
Which of these is a tissue?
Answer: B
A tissue is a group of similar cells doing one job, like the layer of muscle cells that churns food. Choice A is a single cell. Choice C is an organ made of several tissues. Choice D is an organ system.
Question 3 of 20 · Multiple Choice
Leg muscle cells need more oxygen during a race. Which two systems work together to deliver it?
Answer: A
The lungs (respiratory) take oxygen into the blood, and the heart and blood vessels (circulatory) carry it to the muscle cells. Choice B describes systems that handle food and wastes, not oxygen. Choice D leaves out the systems that bring oxygen in and move it around.
Question 4 of 20 · Multiple Choice
Which two systems both remove wastes from the blood?
Answer: C
The kidneys (excretory system) filter wastes out of the blood into urine, and the lungs (respiratory system) remove carbon dioxide that the blood carries from the cells. Choice A names systems that do not filter the blood. Choice B names systems that send signals and move the body.
Question 5 of 20 · Multiple Choice
In a squeeze test, a student's count drops from 60 to 45 squeezes per 30 seconds. By what percent did the count drop?
Answer: D
The drop is 60 - 45 = 15, and 15 ÷ 60 = 0.25 = 25%. Choice A gives the drop in squeezes, not the percent. Choice B divides by the final count, 15 ÷ 45. Choice C gives 45 ÷ 60, the percent that is left.
Question 6 of 20 · Multiple Choice
A person's kidneys stop working. Within days, wastes build up in the blood, and the person feels weak and confused. Which statement best explains why other systems are affected?
Answer: B
The excretory system cleans the blood, and the circulatory system carries that blood to every organ, so wastes left in the blood reach the brain and muscles too. Choice A is wrong: the kidneys filter blood; they do not send nerve signals. Choice D is false: the heart keeps beating, which is why the wastes spread.
Question 7 of 20 · Multiple Choice
You step on a sharp pebble with a bare foot and lift your foot before you even think about it. Which two systems interact most directly?
Answer: A
Nerve endings in the sole of the foot send a signal along nerves (nervous system), and a signal goes back to leg muscles, which contract (muscular system). Choices B, C and D name systems that do not carry or answer the signal.
Question 8 of 20 · Multiple Choice
During a swim race, a swimmer's breathing rises from 16 to 40 breaths per minute. How many times as fast is she breathing?
Answer: D
40 ÷ 16 = 2.5, so she breathes 2.5 times as fast. Choice A gives the difference, 40 - 16. Choice B divides the wrong way, 16 ÷ 40. Choice C adds the two rates.
Question 9 of 20 · Multiple Choice
Which evidence best supports the claim that the digestive and circulatory systems interact?
Answer: C
Blood picking up food materials in the small intestine shows something passing from one system to the other. Choices A, B and D each describe the digestive system alone, which does not show an interaction.
Question 10 of 20 · Multiple Choice
After a big lunch, more blood flows to the stomach and intestines for a while, and hard running feels more difficult. Which interaction does this show?
Answer: B
The circulatory system supplies both the digestive organs and the muscles. When more blood goes to the stomach and intestines, less extra blood, with its oxygen and food, is ready for the leg muscles. Choice D skips the blood, which carries food materials to the muscles. Choice C is false: the kidneys keep filtering blood.
Question 11 of 20 · Multiple Choice
Why is a lung called an organ and not a tissue?
Answer: A
An organ is built from two or more kinds of tissue: a lung has airway tissue, air-sac lining tissue, muscle tissue and blood vessels. Choice C describes a tissue, not an organ. Choice D is false: the lungs need blood flow and nerve signals to work.
Question 12 of 20 · Multiple Choice
Blood flows through an adult's kidneys at about 1.2 L per minute (rounded). About how much blood flows through them in one hour?
Answer: C
1.2 L per minute × 60 minutes = 72 L. Choice A divides 60 by 1.2. Choice B adds 1.2 and 60. Choice D multiplies by 6 instead of 60.
Question 13 of 20 · Multiple Choice
When you smell food you like, your mouth makes more saliva, a liquid that starts digestion. Which two systems interact?
Answer: A
Smell receptors and the brain (nervous system) signal the saliva glands, which are part of the digestive system. Choice D names two systems that interact often, but not in this response. Choices B and C do not involve the signal or the saliva.
Question 14 of 20 · Multiple Choice
Why can a single muscle cell not move your arm?
Answer: D
Moving an arm takes many muscle cells grouped into muscle tissue and whole muscles, pulling together when nerves signal them. Choice C is wrong: muscle cells do receive nerve signals, but one cell alone is far too weak. Choice A is false: a muscle cell is very thin and much smaller than the arm.
Question 15 of 20 · Short Answer
Invented data: before jumping rope, a student takes 15 breaths and 72 beats per minute. After 3 minutes of fast dancing: 36 breaths and 126 beats per minute. How many times faster is each? Write an argument about which systems interact and why.
Breathing: 36 ÷ 15 = 2.4 times. Pulse: 126 ÷ 72 = 1.75 times. Claim: the respiratory, circulatory and muscular systems interact during exercise. Evidence: breathing and pulse both rose while the muscles worked. Reasoning: working muscle cells need more oxygen, so the lungs take in more and the heart pumps the oxygen-rich blood faster; the nervous system signals both changes.
Question 16 of 20 · Short Answer
Give the levels from cell to organ system for the lungs, and name one other system the respiratory system depends on, with what passes between them.
Cells: air-sac lining cells. Tissue: the thin lining tissue of the air sacs. Organ: a lung, which also has muscle and blood vessel tissue. System: the respiratory system. It depends on the circulatory system, which carries oxygen from the lungs to cells and carbon dioxide back to the lungs (or on the nervous system, which signals each breath).
Question 17 of 20 · Short Answer
After a race ends, a runner keeps breathing fast for a few minutes. Explain this with two systems.
Her muscle cells used extra oxygen and released extra carbon dioxide during the race. For a few minutes afterward, the circulatory system is still carrying extra carbon dioxide to the lungs and extra oxygen to the muscles, so the respiratory system keeps working fast until the cells are back to normal. The nervous system signals the breathing rate.
Question 18 of 20 · Short Answer
At rest, a person takes about 12 breaths per minute, and each breath moves about 0.5 L of air (rounded). How much air is that per minute and per hour? Explain how this air helps a muscle cell.
12 × 0.5 = 6 L per minute, and 6 × 60 = 360 L per hour. Oxygen from that air enters the blood in the lungs (respiratory to circulatory), and the blood carries it to muscle cells, which use it to keep working.
Question 19 of 20 · Short Answer
A student says, "The nervous system controls everything, so it does not need the other systems." Respond with evidence.
The claim is not supported. Nerve cells are cells too: they need oxygen from the respiratory system and food materials from the digestive system, both carried by the circulatory system, and their wastes are removed by the excretory and respiratory systems. If blood flow to the brain stops, nerve cells stop working within minutes. The systems depend on each other.
Question 20 of 20 · Short Answer
Using Activity 1, explain why the clothespin count drops faster with the arm raised. Name the levels from cell to system for the muscle and two systems that interact.
Muscle cells in the forearm form muscle tissue, which forms the forearm muscles (organs) of the muscular system. With the arm raised, the circulatory system has to push blood uphill, so less blood, carrying oxygen and food, reaches the muscle cells, and they tire faster. The nervous system signals each squeeze and sends the burning feeling.
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does MS-LS1-3 mean?
MS-LS1-3 asks students to argue, using evidence, that the body is a system of interacting subsystems made of groups of cells. Students show that cells form tissues, tissues form organs and organs form systems, and they use data to show the systems working together. The code means Middle School, Life Science, core idea 1 (From Molecules to Organisms: Structures and Processes), performance expectation 3.
Which body systems are included in MS-LS1-3?
Six: the circulatory, excretory, digestive, respiratory, muscular and nervous systems. The Assessment Boundary limits assessment to these. Other systems, such as the skeletal, immune and endocrine systems, can come up in class discussion but are beyond this standard.
What is the assessment boundary for MS-LS1-3?
Assessment does not include the mechanism of one body system on its own, and it is limited to the six systems listed above. So students are not asked, for example, to trace every step of digestion or every chamber of the heart. They are asked how systems work together and why that matters for the body.
What is the difference between a tissue and an organ?
A tissue is a group of similar cells doing one job, such as muscle tissue or nerve tissue. An organ is a body part made of two or more kinds of tissue working together. For example, the small intestine has lining tissue, muscle tissue and nerve tissue.
What does "interacting subsystems" mean?
Each organ system is a subsystem: a smaller system inside the whole body. They interact when one passes something the other needs, such as oxygen from the lungs into the blood, or a nerve signal that makes a muscle contract. An argument for MS-LS1-3 names the systems and what passes between them.
What counts as evidence for MS-LS1-3?
Measurements students collect (squeeze counts, breathing rates), data sets from cases, and observations of what happens when one system has a problem. Strong evidence compares two conditions, such as before and after exercise, and uses numbers. A list of what each organ does is not evidence of interaction on its own.
Is it safe to measure students' bodies in class?
The activities on this page are light: squeezing a clothespin and counting breaths. Students with injuries or health conditions should not be pushed to take part; they can time, record or use the invented data sets instead. Never ask students to share health information, and keep any personal data anonymous.
What mistakes do students make with body systems?
Common mistakes are describing each system on its own instead of how they connect, calling an organ a tissue, thinking food travels through the body inside nerves or the stomach rather than the blood, and confusing the excretory system with the digestive system. Many students also think breathing speeds up because the lungs need exercise.
What grade is MS-LS1-3 taught in?
It is a grades 6-8 standard, and the grade varies by state and school. Many schools teach it in grade 7 life science, after the cell standards MS-LS1-1 and MS-LS1-2.
How does MS-LS1-3 connect to other standards?
It builds on MS-LS1-1 and MS-LS1-2 (cells and their parts) and works alongside MS-LS1-8 (sensory receptors and the brain). In high school, HS-LS1-2 models the levels of organization in more detail, and HS-LS1-3 investigates how feedback keeps conditions in the body steady.
07
Related Standards
5 standards
These standards connect to MS-LS1-3: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
4-LS1-1Prerequisite
Argue that plant and animal structures support survival, growth, behavior and reproduction
Lesson coming soon
Alongside
MS-LS1-2Parallel
Model how a cell works as a whole and how its parts contribute
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