MS-LS2-1: Analyzing Data on How Resources Affect Organisms and Populations
In plain English: MS-LS2-1 is the NGSS middle school performance expectation that asks students to analyze and interpret data as evidence for how resource availability affects organisms and populations in an ecosystem. Students link abundant or scarce food, water and space to the growth of individuals and to changes in population size. It is usually taught in grade 6, 7 or 8 life science.
Analyze and interpret data to provide evidence for the effects of resource availability on organisms and populations of organisms in an ecosystem.
Clarification Statement: Emphasis is on cause and effect relationships between resources and growth of individual organisms and the numbers of organisms in ecosystems during periods of abundant and scarce resources.
Next Generation Science Standards · Disciplinary Core Idea: Ecosystems: Interactions, Energy, and Dynamics · Official standard
Students analyze data to find out what happens to living things when resources, the things organisms need from their surroundings such as food, water, space and shelter, become abundant (plentiful) or scarce (in short supply). They look for two kinds of effects. For an individual organism, a resource can change how fast and how large it grows. For a population, all the members of one species living in one area, a resource can change how many are born, how many survive and how many move in or out. An ecosystem is all the living things in an area together with their nonliving surroundings. Students read tables and graphs, compute means and percent changes, and write claims supported by data.
The NGSS Clarification Statement says: "Emphasis is on cause and effect relationships between resources and growth of individual organisms and the numbers of organisms in ecosystems during periods of abundant and scarce resources." MS-LS2-1 has no Assessment Boundary. All data on this page are invented for teaching, but the sizes and numbers are typical of the real organisms named. The lab activities use paper dots, clothespins and, if the teacher chooses, closed fruit fly vials.
Learning Objectives
By the end of this lesson, students will be able to:
Read tables and graphs to describe how a resource changed during periods of abundance and scarcity
Use data, including means, to show how resource availability affects the growth of individual organisms
Use data, including percent change, to show how resource availability affects the number of organisms in a population
Identify cause and effect in data, including effects that show up a season or a year later
Write a claim supported by data, and judge whether a data set is strong enough to support a claim
Prior Knowledge Required
Students should already be comfortable with:
Organisms get food, water and shelter from their environment 5-LS2-1
In a habitat, some organisms survive well and some do not 3-LS4-3
Reading bar graphs and line graphs, and finding a mean 6.SP.B.5
Show two photos: an oak forest floor covered with acorns, and the same floor the next fall with almost none. Ask:
Warm-Up Prompt
"Mice in this forest eat acorns. Predict what happens to one mouse, and to the number of mice, in a year with lots of acorns and in a year with almost none. What data would you want to test your prediction?"
Collect predictions in two columns: "one mouse" and "all the mice." Point out that these are the two kinds of effects the lesson tracks: on individual organisms and on populations.
Direct Instruction15 minutes
Resources, individuals and populations. Define resource, abundant, scarce, individual organism and population. Explain that a cause and effect relationship means one change (the cause, such as more food) makes another change happen (the effect, such as heavier chicks). In data, look for the cause first, then the effect, and remember that some effects show up later: young animals born next spring were fed by this fall's food. Model each example on the board and then use Diagram 1.
Population: acorns and mice (invented data, Diagram 1)
In one oak forest, acorns on the ground each fall were 3, 45, 6 and 4 per m² in Years 1-4. White-footed mice counted the next summer were 12, 58, 15 and 11 per hectare (a hectare is a square 100 m on each side).
Result: After the abundant crop of Year 2, mice rose from 12 to 58 per hectare, almost 5 times as many (58 ÷ 12 ≈ 4.8). When acorns were scarce again, mice fell to 15 and then 11. The effect shows up the summer after the acorns, because mice that ate well over winter raised more young in spring.
Individual growth: perch in a lake (invented data)
Yellow perch in a lake eat zooplankton (tiny floating animals). In years with abundant zooplankton, two-year-old perch averaged 14.2 cm long. In years with scarce zooplankton, they averaged 10.6 cm.
Result: Difference: 14.2 - 10.6 = 3.6 cm. Percent: 3.6 ÷ 10.6 ≈ 0.34, so perch grew about 34% longer when food was abundant. The resource affected the growth of each individual fish.
Space as a resource: tree swallows (invented data)
Tree swallows nest in holes. A field had only 4 old tree holes, and 4 pairs nested there each year for five years, even though flying insects (their food) were plentiful. Then 20 nest boxes were put up. The next spring, 17 pairs nested.
Result: Nesting pairs rose from 4 to 17 when nest sites became abundant, while food stayed the same. Nest space, not food, was the scarce resource limiting this population.
Population in one place: hummingbirds and flowers (invented data)
In a mountain meadow, flowers per 100 m² were 40 in June, 120 in July and 30 in August. Hummingbirds seen per hour of watching were 3, 11 and 2.
Result: Hummingbirds rose when flowers were abundant and fell when flowers became scarce. Here the change came quickly, within the same month, because hummingbirds fly in from nearby areas to find food and leave when it runs out.
For each example ask: "What is the resource? Is it abundant or scarce? Is the effect on individuals, on the population, or both? How soon does the effect show up?"
Guided Practice15 minutes
Pairs analyze invented data from one puffin colony. Puffins are seabirds that carry small fish to their chicks in their beaks; one beakful is called a load. Researchers recorded how many loads each chick received per day, how heavy the chicks were when they left the nest (fledging) and how many chicks fledged per 100 nesting burrows.
Invented data: one puffin colony, five summers
Year
Fish loads per chick per day
Mean chick mass at fledging (g)
Chicks fledged per 100 burrows
2019
8
300
72
2020
3
230
31
2021
6
280
60
2022
4
245
40
2023
7
290
66
Plot fish loads (horizontal axis) against mean chick mass (vertical axis). Compare your graph with Diagram 2.
Describe the pattern in one sentence. Which year had the scarcest food?
Use the last column: what happened to the number of chicks fledged in the scarce year?
Write a claim about the effect of food on individual chicks and a second claim about the effect on the population, each citing numbers.
Discuss: the year with only 3 loads per day had the lightest chicks (230 g) and the fewest chicks fledged (31 per 100 burrows). The same resource affected both individuals and the population.
Independent Practice10-15 minutes
Each student analyzes invented data on kangaroo rats, desert rodents that eat seeds. Winter rain makes desert plants produce seeds in spring.
Invented data: winter rain and kangaroo rats the following year
Winter
Rain (mm)
Kangaroo rats per hectare the next year
2018
60
9
2019
180
31
2020
110
20
2021
40
6
Students (1) order the winters from wettest to driest, (2) describe how the rat numbers change with the rain, (3) explain the chain of cause and effect from rain to seeds to rats, and (4) say what other data would make the claim stronger (for example, seed counts each spring).
Closure5 minutes
Return to the warm-up predictions and compare them with Diagram 1. Exit ticket: "Name one resource from today. Write one sentence about its effect on individual organisms and one about its effect on a population, each with a number from the data."
Differentiation Strategies
For Struggling Students
Give a two-column organizer, "cause (resource)" and "effect (individuals or population)", to fill in for each data set
Provide partly drawn axes with labels and scales for the graphing tasks
Use sentence frames: "When ___ was abundant, ___ increased from ___ to ___."
For Advanced Students
Ask students to explain why a population may keep growing for a while after a resource becomes scarce, and to find this in a data set
Have students compare two resources in one ecosystem and argue which one limits the population, using data
Ask students to design a fair test with fruit flies or snails that changes only the amount of food
Assessment Guidance
What to Look For
Check that students name the resource (the cause) and the effect, and say whether the effect is on individual organisms (growth, size, mass) or on a population (numbers). Look for claims that cite specific numbers from the data, and for students who notice delays, such as a population that rises the year after an abundant crop. Watch for claims that go beyond the data, such as using one year or one animal to make a rule about all animals.
02
Classroom Activities
3 Activities
1
Clothespin Birds: A Seed Supply Simulation
25 minWhole class, then pairs
Students act as small seed-eating birds in winter. Each "bird" uses a clothespin as a beak to pick up paper dots (seeds) from a carpet square for 20 seconds. The class runs an abundant round and then a scarce round and records data on individuals (seeds per bird) and on the population (how many birds survive and raise young).
Rules
A bird needs at least 6 seeds to survive the winter.
A bird with 10 or more seeds also raises one young bird, which joins the next round.
Birds that do not survive sit out the next round and help count.
Round 1 (abundant): 120 seeds for 10 birds. Round 2 (scarce): 60 seeds for all the birds from Round 1 plus their young.
How many birds survived Round 1, and how many young did they raise? How many birds started Round 2?
Find the mean seeds per bird in each round. What happened to the individual birds when seeds were scarce?
How many birds survived Round 2? Describe the change in the population from the start of Round 1 to the end of Round 2.
In the real world, what could stand for the paper dots and the clothespins? What does the model leave out?
Modification for Distance Learning
Students run the simulation at home with dried pasta pieces or paper scraps and a spoon, or analyze the sample data and post their graph.
2
Fruit Fly Vial Investigation: Food and Numbers
20 min per session (3 weeks)Groups of 3-4
Groups test how the amount of food affects a fruit fly population. The teacher prepares closed vials with 2 g, 4 g or 8 g of instant fruit fly medium (a lab product, not food for people) and adds 2 male and 2 female flies to each. Over three weeks, groups count adult flies through the closed vials with a hand lens and note their size.
Procedure
Label each vial with the amount of medium and keep all vials at room temperature on the same shelf.
Count the adult flies through the closed vial on days 7, 14 and 21, without opening it.
On day 21, compare the size of the flies in each vial with a hand lens.
Safety and care: use flies from a biological supply company and never release them outdoors. Vials stay closed with foam plugs. At the end, the teacher disposes of the flies by freezing the closed vials, or by another method the school or supplier approves, such as the morgue jar that comes with many commercial fruit fly kits. Check the school's policy on live organisms first.
Sample Data (invented, adults on day 21)
2 g vial: 38 adults, many of them small. 4 g vial: 85 adults. 8 g vial: 160 adults, most of them full size.
Discussion Questions
How did the number of adults change each time the food doubled?
What evidence is there of an effect on individual flies as well as on the population?
Why must every vial start with the same number of flies and sit on the same shelf?
Modification for Distance Learning
Use the sample data. Students draw a bar graph of adults against grams of food and write a claim with evidence.
3
Data Stations: Abundant and Scarce
25 minGroups of 3-4
Four stations each show one invented data set. At each station, groups name the resource, decide whether the effect is on individuals, on the population or both, and write a claim with numbers. Groups rotate every 6 minutes.
Station Data (invented)
Station 1, bighorn sheep: lambs per 100 ewes (adult females) after wet springs with lush grass: 62 and 58; after dry springs: 31 and 27.
Station 2, mosquitofish in tanks: after 6 weeks, a tank fed 1 pinch of fish food per day had 14 young and females averaged 30 mm long; a tank fed 3 pinches per day had 41 young and females averaged 36 mm.
Station 3, barn owls: in years with many voles (their main food), nests held 6.1 eggs on average and fledged 4.5 chicks; in years with few voles, nests held 3.8 eggs and fledged 1.9 chicks.
Station 4, damselfish on a reef: reef patches with 2, 4 and 8 coral heads for shelter held 5, 11 and 19 damselfish.
Discussion Questions
At which station is the resource shelter rather than food? How do the data show that it matters?
Station 2 shows effects on both individuals and the population. Which numbers show each?
At Station 3, the number of chicks fledged per nest fell by more than half in years with few voles. Check this with the data.
Which station has the weakest evidence, and what data would make it stronger?
Modification for Distance Learning
Post each station as a slide. Groups record claims in a shared table during breakout rooms.
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: Acorn Crops and Mice the Next Summer (Invented Data)
Invented data from one oak forest, drawn to scale. Panel A shows acorns on the ground each fall; Panel B shows white-footed mice counted the following summer. The abundant acorn crop of Year 2 is followed by a jump in mice; scarce crops are followed by low numbers.
Diagram 2: Food Delivered and Puffin Chick Mass (Invented Data)
The guided practice data, drawn to scale: each point is one summer at one puffin colony. Chicks that received more fish loads per day were heavier when they left the nest.
04
Homework Assignment
~30 min
MS-LS2-1 Homework: Reading the Evidence on Resources
Directions: All data are invented for practice. For each problem, name the resource, say whether it was abundant or scarce, and say whether the effect is on individual organisms, on a population, or both. Show your calculations and cite numbers in every claim.
Part 1: Effects on Individual Organisms (Problems 1-2)
Elk calves in one valley were weighed each fall. After summers with good rain and plenty of grass, three calves weighed 120, 125 and 118 kg. After dry summers with little grass, three calves weighed 97, 101 and 96 kg. (a) Find the mean mass for each group. (b) How many kilograms heavier were the good-year calves on average? (c) About what percent lighter were the dry-year calves than the good-year calves? (d) Write a claim about grass and calf growth.
Lady beetle (ladybug) larvae eat aphids. In a classroom study, larvae given plenty of aphids became adults in 18 days and were 6.8 mm long. Larvae given few aphids took 25 days and were 5.2 mm long. (a) How much longer did the scarce-food larvae take to become adults? (b) How much shorter were they? (c) Explain how one resource changed two things about each individual.
Part 2: Effects on Populations (Problems 3-4)
Prairie dogs eat grass. Spring and summer rain and the number of pups per 10 burrows in one colony were: 2019, 410 mm and 28 pups; 2020, 250 mm and 14; 2021, 380 mm and 25; 2022, 190 mm and 9; 2023, 330 mm and 21. (a) Make a graph of pups against rain. (b) Describe the pattern. (c) By what percent did the number of pups per 10 burrows fall from 2021 to 2022? (d) Explain the cause and effect chain from rain to pups.
Water fleas (tiny animals called Daphnia) eat algae in a pond. Weekly counts in spring were: algae (relative amount) 20, 60, 90, 50, 15 and 10 in weeks 1-6, and water fleas per liter 5, 12, 40, 75, 30 and 8. (a) In which week did each one peak? (b) Why do you think the water fleas peaked after the algae? (c) What happened to the water flea population once the algae became scarce, and why?
Part 3: Interpret and Argue (Problems 5-6)
A news story says: "More bears are coming into town this year because the bear population exploded." Park data: the berry crop index (0 = none, 10 = huge) was 8 last year and 2 this year. Bear visits to town were 6 last year and 31 this year. Estimated bears living in the park were 120 last year and 118 this year. (a) Do the data support the news story's claim? Explain with numbers. (b) Write a better claim that uses the berry data. (c) Is this an effect on individual bears, on the population, or both?
A shellfish farm hangs ropes in one bay, so every rope gets water with the same amount of plankton (tiny living things that mussels filter from the water as food). Ropes seeded with 900 young mussels per meter grew mussels averaging 4.0 cm long after one year. Ropes seeded with 300 young mussels per meter grew mussels averaging 6.0 cm long. (a) How many times as many mussels per meter do the crowded ropes have? (b) If the same amount of plankton reaches each meter of rope, how does the food available per mussel compare? (c) Use the data to explain how the size of a population can change the growth of each individual.
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
Reading Data
Correct means, differences, percents and graphs with units
One calculation or graphing error
Cause and Effect
Names the resource and the effect, and tells individual effects from population effects
Names the effect but not the resource, or mixes up individuals and populations
Claims from Evidence
Every claim cites numbers and stays within what the data show
Claim is general or goes beyond the data
05
Quiz: 20 Questions
Interactive, with answers
Instructions
All data are invented, but the organisms and sizes are realistic. 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 of these is a resource for a population of rabbits in a meadow?
Answer: B
A resource is something an organism needs and uses from its surroundings, such as food, water, space or shelter: clover and grass are food. Choice A is a predator, not a resource. Choice C is a population measurement, and choice D is a weather condition.
Question 2 of 20 · Multiple Choice
Invented data: in wet years a meadow had 900 seeds per m² and 24 nesting sparrow pairs; in dry years it had 200 seeds per m² and 9 pairs. Which claim do the data best support?
Answer: C
When seeds were abundant, more pairs nested (24 against 9). Choice A reverses cause and effect: the seeds come from rain and plants, not from the birds. Choice B ignores the clear difference. Choice D is about individual size, which these data do not measure.
Question 3 of 20 · Multiple Choice
Invented data: mule deer fawns born after a dry spring weighed less at 4 months old than fawns born after a wet spring. What kind of effect is this?
Answer: A
Mass at 4 months is a measure of how each fawn grew, so this is an effect on individual organisms. Choice B would need counts of fawns. Choice C has the cause and effect backward, and choice D ignores the mass difference.
Question 4 of 20 · Multiple Choice
Five mountain goat kids weighed 18, 23, 19, 22 and 18 kg in autumn of a year with poor plant growth. What is their mean mass?
Answer: B
The sum is 18 + 23 + 19 + 22 + 18 = 100 kg, and 100 ÷ 5 = 20 kg. Choice A is the median, choice C is the sum before dividing, and choice D is the mode (the value that appears most often).
Question 5 of 20 · Multiple Choice
A population of wrens fell from 200 pairs to 150 pairs after a winter with few insects. What was the percent decrease?
Answer: C
The decrease is 200 - 150 = 50 pairs, and 50 ÷ 200 = 0.25, or 25%. Choice A is the number of pairs lost written as a percent. Choice B divides by the new number, 150. Choice D is the share that remained (150 ÷ 200).
Question 6 of 20 · Multiple Choice
Invented data: a pine forest produced 2, 30, 3 and 4 million cones in Years 1-4. Red squirrels eat the seeds in the cones over winter and have young in spring. In which spring do the data predict the most young squirrels?
Answer: A
The huge cone crop came in the fall of Year 2, so squirrels were best fed during the winter after it and raised the most young the next spring. Choice D picks the spring after a small crop. Choice C picks the last year in the table, not the year after the large crop.
Question 7 of 20 · Multiple Choice
A population has plenty of food at first, so it grows quickly. Then the food becomes scarce. What does the data most often show next?
Answer: B
When a resource becomes scarce, fewer young are born and survive, so growth slows and numbers may drop. Choice A ignores the scarce resource. Choice D is backward: scarce food usually means slower growth of individuals.
Question 8 of 20 · Multiple Choice
A pond supplies about 600 g of insect larvae per day for its sunfish. The population grows from 40 to 60 fish while the food stays the same. How much food is available per fish now?
Answer: D
600 ÷ 60 = 10 g per fish. Choice A is the amount before the population grew (600 ÷ 40). Choice B is the drop in food per fish (15 - 10), and choice C is the total for the whole pond.
Question 9 of 20 · Multiple Choice
A student claims that a drought caused a drop in a lizard population. She has lizard counts for the drought year only. Which new data would best strengthen her claim?
Answer: C
To show cause and effect, she needs data from years with and without drought, plus data on the resource (insects) that links the drought to the lizards. Choices A, B and D do not compare abundant and scarce periods.
Question 10 of 20 · Multiple Choice
Two classes test how food affects crickets. Which plan is a fair test?
Answer: A
Only the amount of food changes in choice A, so any difference can be linked to food. Choice B also changes temperature, and choice C changes the starting number of crickets. Choice D has nothing to compare with.
Question 11 of 20 · Multiple Choice
Invented data: an island had 60 seed-eating mice when seeds were abundant. After two years of scarce seeds, it had 20 mice. Which statement describes the data?
Answer: A
20 ÷ 60 = 1/3, so the population fell to one third. Choice B confuses the final number with the change (a drop of 40 mice). Choice C reverses the direction, and choice D uses the wrong fraction.
Question 12 of 20 · Multiple Choice
In a summer with abundant insects, 30 female American robins in a town park raised 84 young (invented data). How many young per female is that?
Answer: B
84 ÷ 30 = 2.8 young per female. Choice A divides 30 by 84, the wrong way around. Choice C subtracts, choice D adds, and neither gives a rate per female.
Question 13 of 20 · Multiple Choice
Which of these is NOT a resource that limits the size of a population?
Answer: C
Feather color is a trait of the bird, not something it takes from its surroundings. Nesting holes, water and hiding places are resources (space, water and shelter) that can be abundant or scarce.
Question 14 of 20 · Multiple Choice
Invented data: after 4 weeks, snails given 2 g of lettuce per day numbered 12 with a mean shell width of 9 mm. Snails given 6 g per day numbered 35 with a mean shell width of 12 mm. Which claim fits the data?
Answer: C
The 6 g tank had more snails (35 against 12), an effect on the population, and wider shells (12 mm against 9 mm), an effect on individuals. Choices A and B each ignore one part of the data, and choice D ignores both differences.
Question 15 of 20 · Short Answer
Brook trout were measured in two streams. In a stream with many insects, five trout were 18, 21, 20, 19 and 22 cm long. In a stream with few insects, five trout were 14, 15, 13, 16 and 12 cm long. Find each mean and the difference, and write a claim.
Means: (18 + 21 + 20 + 19 + 22) ÷ 5 = 20 cm, and (14 + 15 + 13 + 16 + 12) ÷ 5 = 14 cm. The difference is 6 cm. Claim: trout in the stream with abundant insects grew longer, by 6 cm on average, so food availability affected the growth of individual fish.
Question 16 of 20 · Short Answer
A beech forest has a huge nut crop one fall. Chipmunk numbers stay about the same that fall but jump the next summer. Explain why the effect is delayed.
The chipmunks eat and store the nuts through the fall and winter, so more of them survive the winter in good condition and they raise more young in spring. The young are counted the next summer, so the population increase shows up after the crop. Full credit links the abundant resource to survival and births and explains the timing.
Question 17 of 20 · Short Answer
A summer drought dries out most of the grass in a valley where grasshoppers live. Predict one effect on individual grasshoppers and one effect on the grasshopper population, and explain each.
Individuals: grasshoppers grow more slowly and stay smaller, because each one finds less food. Population: fewer young survive and fewer eggs are laid, so the number of grasshoppers drops the next year. Full credit gives one prediction for each level with a reason based on the scarce resource.
Question 18 of 20 · Short Answer
Invented data: an insect index (higher means more insects) of 2, 5 and 8 in three summers matched 150, 300 and 420 bats returning to a barn roost. Describe the pattern and explain what it suggests.
As the insect index rose from 2 to 8, the number of bats rose from 150 to 420, so more insects were linked to more bats at the roost. It suggests that abundant food supports a larger bat population, either because more bats survive and raise young or because more bats move in. Full credit describes the direction of the pattern with numbers and links it to food as a resource.
Question 19 of 20 · Short Answer
A student looks at data from one year at one pond and claims, "Frogs always have more young when there are more insects." Explain why the claim goes beyond the data, and say what data would test it.
One year at one pond cannot show what always happens: there is no comparison between years with many and few insects, and only one place was studied. Better data: frog young and insect counts for several years, or for several ponds, including both abundant and scarce insect years. Full credit names the missing comparison and suggests a data set.
Question 20 of 20 · Short Answer
A lake's zooplankton drops sharply after a very cold spring. Describe one way this could affect individual fish and one way it could affect the fish population, and name the data you would collect to check each.
Individuals: young fish grow more slowly, so they are shorter at the same age; check by measuring the length of fish of the same age in this year and in earlier years. Population: fewer young fish survive, so fewer fish are counted the next year; check with yearly counts or net samples. Full credit gives both effects and a matching data set for each.
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does MS-LS2-1 mean?
MS-LS2-1 asks middle school students to analyze and interpret data as evidence for the effects of resource availability on organisms and populations in an ecosystem. The code means Middle School, Life Science, core idea 2 (Ecosystems: Interactions, Energy, and Dynamics), performance expectation 1.
What counts as a resource in MS-LS2-1?
Anything organisms need and take from their surroundings: food, water, space, shelter, nesting sites and, for plants, light and minerals. A resource can be abundant (plentiful) or scarce (in short supply), and the data compare the two.
What is the difference between an effect on an organism and an effect on a population?
An effect on an individual organism changes one living thing: how fast it grows, how large or heavy it gets, or how long it takes to become an adult. An effect on a population changes the number of organisms: births, deaths, and animals moving in or out. Many data sets show both.
Does MS-LS2-1 have an Assessment Boundary?
No. MS-LS2-1 has a Clarification Statement but no Assessment Boundary. The Clarification Statement puts the emphasis on cause and effect between resources and both the growth of individuals and the numbers of organisms, in periods of abundant and scarce resources.
What math do students use in MS-LS2-1?
Middle school math is enough: reading tables and graphs, finding means, differences and ratios, and computing percent change. The science skill is interpreting the numbers: naming the cause, the effect and the evidence.
Do these data prove that a resource caused the change?
Not by themselves. Two things that rise and fall together are linked, but something else could cause both. Evidence for cause and effect gets stronger when the pattern repeats over many years or places, when a known way links the resource to the organisms (for example, the animals eat it), and when a fair test changes only the resource, as in the fruit fly vials.
Are the data on this page real?
No. All data are invented for teaching, so the numbers are simple to work with. The organisms are real, and their sizes and numbers were kept within typical ranges, such as perch about 10-15 cm long at two years old.
Can students collect their own data for MS-LS2-1?
Yes. A clothespin-and-paper-dot simulation takes one class period, and a fruit fly vial investigation with different amounts of food takes about three weeks. Both let students compare abundant and scarce resources directly.
How does MS-LS2-1 connect to other middle school standards?
MS-LS2-2 looks at patterns of interactions such as competition and predation, which often happen because resources are limited, and MS-LS2-4 asks for arguments about how changes to an ecosystem affect populations. MS-LS2-1 gives students the data skills for both.
What comes after MS-LS2-1 in high school?
In high school, HS-LS2-1 uses mathematical representations to explain carrying capacity, the largest population an ecosystem can support, and HS-LS2-2 uses math to explain changes in biodiversity and populations. Both build on reading resource and population data.
07
Related Standards
6 standards
These standards connect to MS-LS2-1: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
3-LS4-3Prerequisite
Argue that in a habitat some organisms survive well, some less well, some not at all
Lesson coming soon
5-LS2-1Prerequisite
Model how matter moves among plants, animals, decomposers and the environment
Lesson coming soon
Alongside
MS-LS2-2Parallel
Explain and predict patterns of interactions among organisms in many ecosystems
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