3-LS3-2: How Surroundings Shape Traits
Also called NGSS 3-LS3-2 · Topic: Inheritance and Variation of Traits: Life Cycles and Traits · Life Science
The Official Wording
Use evidence to support the explanation that traits can be influenced by the environment.
Clarification statement: Examples of the environment affecting a trait could include normally tall plants grown with insufficient water are stunted; and, a pet dog that is given too much food and little exercise may become overweight.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What 3-LS3-2 Means in Plain English
Third graders gather evidence that where a living thing grows up can change some of its traits. A plant given little water grows shorter than one with plenty, and a pet that overeats and rarely runs may gain extra weight.
Students compare living things that start out alike and grow up in different conditions, without studying genes. It builds on inherited traits in 3-LS3-1 and leads to MS-LS1-5, where surroundings and genes together shape how living things grow.
3-LS3-2 I Can Statements
- I can explain that surroundings can change some traits.
- I can compare living things raised in different conditions.
- I can use measurements as evidence for my explanation.
3-LS3-2 Worked Example
A two-week growing test with two trays of wheatgrass from the same bag of seed.
Does the amount of water change how tall wheatgrass grows?
Set It Up: Two trays of potting soil sown with wheatgrass seed from one bag, a measuring cup, and a centimeter ruler.
- Sow the same amount of seed in each tray and set both in the same sunny spot.Same seed, soil and light
- Give Tray A a half cup of water every day and Tray B a half cup every four days.Only the water changes
- Measure five blades in each tray on day 6.A: about 6 cm. B: about 3 cm
- Measure again on day 12 and note the color.A: about 15 cm, bright green. B: about 6 cm, yellow tips
- Find the typical height for each tray and compare.Tray A more than twice as tall
The well-watered wheatgrass grew more than twice as tall as the dry tray, even though all the seed came from one bag.
Why it works: Seeds from one bag start out alike, so the height difference came from the water, which shows surroundings can change a trait like height.
Common Mistakes with 3-LS3-2
Thinking every trait comes from parents
“The short grass just had short parents.”
Try this: Point out that both trays used seed from one bag. When the start is the same, the difference comes from the surroundings.
Changing more than the water
Tray B sits in a dark corner and gets less water
Try this: Keep light, soil and seed the same for both trays, so water is the only thing that could explain the difference.
Measuring just one blade
Picking the tallest blade in Tray B and calling it the winner
Try this: Measure several blades in each tray and compare the typical heights, so one unusual blade does not decide the result.
Where 3-LS3-2 Fits
Practice 3-LS3-2
Quick Check
- Two plants from the same seed packet grow to different heights. What could cause that?
- A dog eats more than it needs and rarely runs. What trait might change?
- In a fair water test, what must stay the same?