MS-LS1-4: How Animal Behaviors and Plant Structures Affect Reproduction
In plain English: MS-LS1-4 is the NGSS middle school performance expectation that asks students to use an argument based on evidence to explain how animal behaviors and specialized plant structures raise or lower the chance that animals and plants reproduce successfully. Students compare data such as chick survival, flower visits and seed counts. It is usually taught in grade 6, 7 or 8 life science.
Use argument based on empirical evidence and scientific reasoning to support an explanation for how characteristic animal behaviors and specialized plant structures affect the probability of successful reproduction of animals and plants respectively.
Clarification Statement: Examples of behaviors that affect the probability of animal reproduction could include nest building to protect young from cold, herding of animals to protect young from predators, and vocalization of animals and colorful plumage to attract mates for breeding. Examples of animal behaviors that affect the probability of plant reproduction could include transferring pollen or seeds, and creating conditions for seed germination and growth. Examples of plant structures could include bright flowers attracting butterflies that transfer pollen, flower nectar and odors that attract insects that transfer pollen, and hard shells on nuts that squirrels bury.
Next Generation Science Standards · Disciplinary Core Idea: From Molecules to Organisms: Structures and Processes · Official standard
Students build arguments from evidence about how animal behaviors (nest building, herding, calls, showy feathers, moving seeds) and specialized plant structures (bright petals, nectar, scent, hard nut shells) change the probability, or chance, that animals and plants reproduce successfully. In every case they compare two groups that differ in one behavior or structure, turn counts into percents, and explain how the difference changes the number of offspring that survive. All data sets on this page are invented for teaching, and no activity uses live animals.
The NGSS Clarification Statement says: "Examples of behaviors that affect the probability of animal reproduction could include nest building to protect young from cold, herding of animals to protect young from predators, and vocalization of animals and colorful plumage to attract mates for breeding. Examples of animal behaviors that affect the probability of plant reproduction could include transferring pollen or seeds, and creating conditions for seed germination and growth. Examples of plant structures could include bright flowers attracting butterflies that transfer pollen, flower nectar and odors that attract insects that transfer pollen, and hard shells on nuts that squirrels bury." MS-LS1-4 has no official Assessment Boundary. Students do the practice of engaging in argument from evidence: they analyze data, write claims backed by numbers, and judge whether evidence is strong or weak.
Learning Objectives
By the end of this lesson, students will be able to:
Explain what successful reproduction and probability mean for animals and plants
Use data from two groups, as percents, to show how an animal behavior changes the probability that the animal's young survive or that it finds a mate
Use data to show how a plant structure, or an animal behavior such as moving pollen or burying nuts, changes the probability that a plant makes seeds that grow
Write an argument with a claim, evidence and reasoning, and judge whether the evidence is strong enough
Prior Knowledge Required
Students should already be comfortable with:
Plants and animals have structures that support survival and reproduction 4-LS1-1
Some animals form groups that help members survive 3-LS2-1
Describe a killdeer, a bird that nests on open gravel. When a fox walks toward its nest, the parent runs away from the eggs, drags one wing on the ground and cries loudly, as if it were hurt. When the fox follows, the bird suddenly flies off.
Warm-Up Prompt
"Why might a killdeer parent act hurt when a fox comes near its nest? What could you count or measure to find out whether this behavior helps the killdeer raise more chicks?"
Collect two or three ideas. Many students say "to protect its babies"; ask what evidence would show that it works. Write their suggested measurements (number of eggs that hatch, number of chicks that live) on the board. The lesson returns to them as the kind of evidence an argument needs.
Direct Instruction15-20 minutes
Key words.Reproduction is making offspring (young). Reproduction is successful when the offspring survive long enough to reproduce themselves. Probability is the chance that something happens, written as a fraction or a percent from 0% (never) to 100% (always). A behavior is something an animal does; a structure is a body part, such as a petal or a shell. Pollen is the powder made by flowers that carries the male cells, and pollination is the move of pollen to the female part of a flower (the stigma) so seeds can form. An animal that carries pollen is a pollinator, and nectar is the sugary liquid many flowers make. Germination is a seed starting to grow.
How the argument works. A behavior or structure cannot guarantee that a baby bird lives or a seed grows. It can only raise or lower the probability. So the evidence compares two groups that differ in one behavior or structure, and the reasoning explains how that difference changes the chance of offspring. When the groups have different sizes, compare percentages, not counts. The difference between two percentages is measured in percentage points: 85% and 60% differ by 25 percentage points. All data on this page are invented for teaching.
Animal behavior, animal reproduction: nest building against cold
Tree swallows line their nests with feathers. On cold mornings (5 °C air) eggs in nests with 15 or more feathers cooled from 36 °C to 31 °C while the parent was away for 10 minutes; eggs in nests with fewer than 5 feathers cooled to 25 °C. Of 100 eggs in each kind of nest, 85 and 60 became chicks that left the nest.
Result: 85 out of 100 = 85% and 60 out of 100 = 60%, a difference of 25 percentage points. Claim: lining the nest with feathers raises the probability that eggs become young birds. Reasoning: feathers trap warmth, so the eggs stay closer to the temperature they need while the parent feeds.
Animal behavior, animal reproduction: herding against predators
When wolves come near, musk oxen often form a tight ring with the calves inside and the adults' horns facing out. In 24 wolf approaches, the herd formed a ring 18 times and a calf was caught 2 times. The other 6 times the herd ran, and a calf was caught 4 times.
Result: Calves safe: 16 of 18 = about 89% with the ring, 2 of 6 = about 33% when the herd ran. Claim: forming a ring raises the probability that calves survive to become adults that breed. Caution: 6 approaches is a small sample.
Animal behavior and trait, animal reproduction: colorful plumage
Male house finches range from pale yellow to bright red. Females choose their mates. Of the 10 reddest males in a study area, 9 had paired with a female by April 1. Of the 10 palest males, 4 had.
Result: 9 of 10 = 90% and 4 of 10 = 40%. Claim: bright red plumage (feathers) raises a male's probability of mating. Reasoning: a male that does not attract a mate has no offspring that season.
Animal behavior, plant reproduction: moving seeds and preparing them to grow
Cedar waxwings swallow small berries whole and drop the seeds, without the fruit pulp, far from the parent shrub. In a germination test, 48 of 80 seeds taken from waxwing droppings sprouted, while 12 of 80 seeds left inside whole fallen berries sprouted.
Result: 48 of 80 = 60% and 12 of 80 = 15%: seeds from droppings were 4 times as likely to sprout. The bird transfers seeds to new places and creates conditions for germination by removing the pulp.
Plant structure, animal behavior: hard shells on nuts that squirrels bury
A gray squirrel buries 40 hickory nuts in the fall, one or two in each spot, about 3 cm deep. The hard shell keeps the nut from rotting for months, so squirrels store such nuts instead of eating them at once. By spring the squirrel has dug up and eaten 31; the other 9 are never found, and 3 of those sprout.
Result: 3 of 40 = 7.5% of the buried nuts became seedlings, and 3 of 9 = 1 in 3 of the forgotten nuts did. A nut eaten on the spot has a 0% chance. The shell makes storing worthwhile, and burying plants the nut at a good depth.
After each example, ask: "Which two groups are compared? What is the one difference between them? How does that difference change the probability of offspring?" Point out that the musk ox evidence is weaker than the swallow evidence because one group has only 6 cases. Diagram 1 shows the first three examples side by side.
Guided Practice10-15 minutes
Pairs analyze invented data from a test garden. A plant breeder grew four kinds (varieties) of one flower species that differ only in petal color, nectar and scent (odor), 40 flowers of each. A fifth group of kind A flowers was covered with fine mesh bags so that no insects could reach them. Students counted insect visits in two hours and later counted the flowers that made seeds.
Guided practice data (invented): one flower species, 40 flowers per kind
Kind
Petals
Nectar
Scent
Insect visits in 2 hours
Flowers that made seeds
A
bright purple
yes
yes
64
34
B
bright purple
yes
no
40
25
C
pale green
yes
yes
30
19
D
pale green
no
no
6
5
E (bagged A)
bright purple
yes
yes
0
2
Turn each "flowers that made seeds" count into a percent of 40. Check your answers against Diagram 2.
Kinds A and B differ only in scent. Write how many more insect visits kind A received and how many more of its flowers made seeds.
Find the two kinds that differ only in petal color. What do the visits and seed counts show about bright petals?
Why did the breeder include the bagged flowers (kind E)? What does the result tell you about who moves the pollen?
Write a claim, two pieces of evidence and one sentence of reasoning that links visits to seeds.
Independent Practice10-15 minutes
Each student writes an argument from a new invented data set about vocalization (making calls or songs). Male gray tree frogs call to attract females in spring. Scientists placed two speakers 2 meters apart at the edge of a pond. One played a long call and the other a short call, at the same loudness. One at a time, 40 female frogs were set down halfway between the speakers and allowed to hop to either one, then let go at the pond. Halfway through, the speakers swapped places.
Independent practice data (invented): 40 female gray tree frogs
Speaker
Females that moved to it
Long call
29
Short call
11
Students find each percent, explain why the scientists swapped the speakers, and write a claim, evidence and reasoning paragraph about how a male's call affects his probability of mating. Ask them what result they would expect if the females did not care about call length.
Closure5 minutes
Exit ticket: "Name one animal behavior and one plant structure from today. For each, write one sentence that says how it changes the probability of successful reproduction and what evidence shows it." Return to the warm-up list of measurements and ask which of them would let the class build an argument about the killdeer.
Differentiation Strategies
For Struggling Students
Give a two-row table with columns for "count", "group size" and "percent" so students fill in each step
Provide a sentence frame: "The data show that ___ % of ___ and ___ % of ___. This supports the claim because ___."
Start with groups of 100 so the count already equals the percent, then move to other group sizes
For Advanced Students
Ask students to find the weakest piece of evidence in the stations and design a study that would make it stronger
Have students weigh a benefit against a cost, such as calling crickets and parasite flies, and argue the overall effect
Ask students to explain why a behavior that lowers an adult's own survival, such as the killdeer display, can still raise its number of offspring
Assessment Guidance
What to Look For
Check that students compare percents, not counts, when the groups differ in size, and that they name both groups in their evidence. Look for reasoning that explains how the behavior or structure changes the chance of offspring surviving, rather than saying the organism "wants" offspring. Listen for students who treat one result as proof or who say a behavior guarantees success.
02
Classroom Activities
3 Activities
1
Flower Dissection: Structures That Recruit Pollinators
25 minPairs
Pairs take apart a store-bought alstroemeria flower (also sold as Peruvian lily) and find the structures that attract pollinators and the ones that make or receive pollen. Then they use a cotton swab as a model pollinator to see how pollen gets carried from one flower to another.
Procedure
Safety: wear disposable gloves, because the sap can bother skin; wash hands afterward; do not taste any part of the flower. Students with pollen allergies may observe and record.
Use a hand lens to find the six colored tepals (petals), the dark stripes on the inner tepals, the six stamens (the stalks with pollen on their tips) and the single pistil, whose tip, the stigma, has three branches.
Gently pull off one inner tepal and look at its base for nectar, a shiny drop or a moist spot.
Brush the cotton swab across the pollen of one flower, then touch it to the stigma of a second flower. Record what you see on the swab and on the stigma.
Record and Argue
Make a three-column table: structure, what it does, how it could change the probability that this plant makes seeds. Include at least the tepals, the stripes, the nectar, the stamens and the stigma.
Discussion Questions
The stripes on the inner tepals point toward the center of the flower. How could they help an insect find the nectar, and why does that matter for the plant?
The pollen sits on the stamens near the nectar. What happens to an insect's body when it reaches for the nectar?
Your swab carried pollen to a second flower. What does the swab stand for, and what part of a real insect's visit does it leave out?
Modification for Distance Learning
Students take apart any garden or grocery flower at home with an adult's permission, photograph each structure next to a ruler, and post a labeled photo with their table.
2
Behavior Evidence Stations
25 minGroups of 3-4
Four stations each give one invented data set about an animal behavior or trait. At each station, groups compute two percentages, find the difference in percentage points and write one claim card that names the behavior, the evidence and the reasoning. Groups rotate every 5 minutes.
Station Data (invented)
Station 1, common eiders (sea ducks that nest in the cold Arctic): females pluck soft down feathers from their bellies to cover the eggs. Of 120 eggs in nests with thick down, 96 hatched. Of 60 eggs in nests with thin down, 30 hatched.
Station 2, bison herds: in 30 wolf chases where the herd bunched together with the calves in the center, a calf was caught 3 times. In 10 chases where the herd scattered, a calf was caught 6 times.
Station 3, peacocks (male peafowl): 10 of 12 males with more than 150 eyespots on their tail feathers mated, and 3 of 12 males with fewer than 130 eyespots mated.
Station 4, dung beetles: the beetles bury balls of animal dung that often contain seeds. 18 of 50 seeds buried by beetles sprouted, and 4 of 50 seeds left on the surface sprouted.
Discussion Questions
Station 3 shows the largest difference in percentage points. Does a larger difference always mean stronger evidence? What else matters?
Station 4 is about an animal behavior that changes a plant's reproduction. Which word from the lesson names what the beetle does for the seed?
At Station 1, more eggs hatched in the thick-down nests, but the two groups are different sizes. Why do the percentages make a fairer comparison than the counts?
Modification for Distance Learning
Post each station as a slide. Groups work in breakout rooms and type one claim card per station into a shared document.
3
Cache and Forget: A Squirrel Model
20 minGroups of 6
Students model how a hard shell and a burying behavior together raise the probability that a nut becomes a tree. Each student plays a squirrel that buries 10 paper "nuts" in a tray of shredded paper, does a 3-minute distracting task, and then has 60 seconds to find as many of its own nuts as possible.
Procedure
Each squirrel writes its initial on 10 paper squares and hides them one at a time in the group's tray of shredded paper, remembering the spots.
Everyone does the same 3-minute task (a short word puzzle), then searches for 60 seconds. Count found and forgotten nuts for the group.
Rule from the model: about 1 in 3 forgotten nuts sprouts. Round 2: the nuts are "soft berries" that spoil, so each squirrel eats all 10 at once instead of burying them.
Sample Data (invented)
One group of 6 squirrels buried 60 nuts and found 42 of them, so 18 were forgotten. Using the 1 in 3 rule, 6 nuts sprout, which is 10% of the buried nuts. In round 2, 0 berries were buried, so 0 seeds were planted.
Discussion Questions
Why does a hard shell make the burying behavior possible in the first place?
The squirrel "loses" the forgotten nuts. Who gains from them, and how?
What part of real seed growth does the 1 in 3 rule leave out? Name one condition a buried nut needs to sprout.
Challenge Variation
Groups predict, then test, what happens to the number of seedlings if the distracting task lasts 6 minutes instead of 3, and explain whether a forgetful squirrel is good or bad for the hickory tree.
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: Three Animal Behaviors or Traits and Their Effect on Reproduction
Invented data from the worked examples, drawn to scale. Each pair of bars compares animals with the behavior or trait (dark) and without it (light): eggs that became young swallows, musk ox calves kept safe from wolves, and male finches that found a mate. In all three pairs the behavior or trait goes with a higher probability of offspring.
Diagram 2: Flower Structures and Seed Production (Guided Practice)
The invented test-garden data, drawn to scale: the percent of 40 flowers of each kind that made seeds. Bright petals, nectar and scent each go with more seeds, and almost no seeds formed when mesh bags kept insects away.
04
Homework Assignment
~30 min
MS-LS1-4 Homework: Arguing From Evidence About Behaviors and Structures
Directions: All data sets are invented for practice. For each problem, show your percents, then write a claim, the evidence you used and one or two sentences of reasoning that explain how the behavior or structure changes the probability of successful reproduction.
Part 1: Animal Behaviors and Animal Reproduction (Problems 1-3)
Adelie penguins build nests from small stones on cold, rocky ground, where melting snow forms icy puddles. Of 80 eggs in nests at least 8 cm high, 70 hatched. Of 60 eggs in nests less than 4 cm high, 36 hatched. (a) Find the percent that hatched in each kind of nest. (b) Find the difference in percentage points. (c) Write an argument about how nest building affects the probability that the penguins reproduce successfully.
Elephant herds bunch around their calves when lions are near. A park team recorded 50 lion encounters. In 40 the herd bunched together and lost a calf 1 time. In 10 the herd stayed spread out and lost a calf 3 times. (a) Find the percent of encounters with a calf lost for each behavior. (b) Write a claim with evidence. (c) Give one reason the evidence about spread-out herds is weaker, and say what data would make it stronger.
Male field crickets chirp at night to attract females. Of 15 males that chirped for more than 3 hours a night, 12 attracted a female. Of 15 males that chirped for less than 1 hour, 4 did. But a kind of fly finds crickets by their sound and drops its tiny larvae on them: 5 of the long-chirping males and 1 of the short-chirping males carried fly larvae. (a) Find all four percents. (b) Use both kinds of evidence to argue whether long chirping raises or lowers a male's probability of reproducing.
Part 2: Plant Structures and Plant Reproduction (Problems 4-6)
Evening primrose flowers are pale yellow and strongly scented, and they open at dusk. A class tested 120 flowers. Of 40 flowers left uncovered day and night, 30 made seed pods. Of 40 flowers covered with mesh bags only at night, 8 made pods. Of 40 covered only during the day, 28 made pods. (a) Find each percent. (b) Which visitors, day or night, move most of the pollen? (c) Argue how the flower's color and scent fit those visitors.
Gray squirrels were offered 100 whole walnuts in hard shells and, on another day, 100 shelled walnut pieces. They buried 70 of the whole walnuts and ate the rest at once. They buried 10 of the shelled pieces and ate the rest at once. Squirrels never find about 1 in 5 of the nuts they bury. (a) How many of each kind were buried? (b) How many of each would be left in the ground? (c) Explain how the hard shell raises the probability that a walnut grows into a tree.
A student walked through a weedy field with old fuzzy socks pulled over her shoes and collected 46 seeds from the socks: 38 had hooks or barbs and 8 were smooth. In that field, 3 of the 10 kinds of plants with ripe seeds had hooked seeds. (a) What percent of the collected seeds had hooks? (b) Write an argument about how hooked seeds affect the probability that a plant's seeds reach new places. (c) Plan one change to the investigation that would make the evidence stronger.
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
Using the Data
Correct percents and differences for every group, with the groups named
Most percents correct, or counts compared when group sizes differ
Claim and Evidence
Claim names the behavior or structure and cites specific numbers from both groups
Claim stated, but the evidence is general or from one group only
Reasoning
Explains how the behavior or structure changes the probability of offspring, and notes limits such as small samples
Reasoning restates the claim or treats the behavior as a guarantee
05
Quiz: 20 Questions
Interactive, with answers
Instructions
All data sets are invented. Turn counts into percents when you compare groups of different sizes. 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
In this standard, when is an animal's or a plant's reproduction called successful?
Answer: C
Reproduction is successful when the offspring survive to reproduce themselves. Choice A counts eggs or seeds, but many may die before they grow up. Choice B stops at mating or flowering, which does not show that any offspring survived.
Question 2 of 20 · Multiple Choice
Barn swallows build mud nests. Under barn roofs, 45 of 60 chicks left the nest. On open cliffs, 18 of 40 chicks left the nest. How many percentage points higher is the success under roofs?
Answer: B
45 of 60 is 75% and 18 of 40 is 45%, so the difference is 75 - 45 = 30 percentage points. Choice A subtracts the counts (45 - 18 = 27), which is unfair because the groups have different sizes. Choice C subtracts the group sizes (60 - 40). Choice D is the cliff percent, not the difference.
Question 3 of 20 · Multiple Choice
Which of these is a specialized plant structure that can raise the probability of pollination?
Answer: A
Nectar is a structure the plant makes, and it rewards animals that visit and pick up pollen. Choice B is an animal behavior, not a plant structure. Choices C and D are conditions in the environment.
Question 4 of 20 · Multiple Choice
A student claims that bright petals raise the number of seeds a plant makes. Which evidence would support the claim best?
Answer: D
Comparing flowers of the same species, some with petals covered by green paper and some uncovered, changes only the petal color seen by insects; counting seeds in both groups tests the claim. Choice A is one flower and no seed count. Choice B measures people, not pollinators. Choice C has no comparison group.
Question 5 of 20 · Multiple Choice
In a playback test, 35 of 50 female frogs moved toward a speaker playing fast calls instead of one playing slow calls. What percent chose the fast calls?
Answer: C
35 ÷ 50 = 0.70, which is 70%. Choice A uses the count as if it were a percent. Choice B is 15 ÷ 50, the females that chose the slow calls. Choice D divides 50 by 35, upside down.
Question 6 of 20 · Multiple Choice
Wildebeest in a herd crowd together when hyenas are near, and calves stay in the middle. Which reasoning links this behavior to successful reproduction?
Answer: A
The behavior lowers the chance that a calf is caught, so more calves grow up and reproduce. Choice B is about warmth, not predators, and the question gives no evidence for it. Choices C and D are absolute claims ("never", "every time") that no data support.
Question 7 of 20 · Multiple Choice
Why does a hard shell on a nut raise the probability that the nut grows into a new tree?
Answer: C
A hard shell keeps the nut from spoiling, so squirrels store it by burying it, and some buried nuts are never dug up and can sprout. Choice D is too strong: squirrels open and eat most of the nuts. Choice A is wrong because the food for the seedling is inside the seed, not in the shell.
Question 8 of 20 · Multiple Choice
Which example shows an animal behavior that affects the reproduction of a plant?
Answer: B
The bat carries the pollen to the next flower it visits, which helps the plant make seeds. Choices A and D are animal behaviors that affect the animal's own reproduction. Choice C is a plant doing something, not an animal.
Question 9 of 20 · Multiple Choice
Thrushes eat berries and drop the seeds. 30 of 50 seeds from thrush droppings sprouted, and 10 of 50 seeds in whole fallen berries sprouted. How do the chances compare?
Answer: D
30 of 50 is 60% and 10 of 50 is 20%, and 60 ÷ 20 = 3. Choice A uses the difference in counts (30 - 10 = 20) as if it were a "times as likely" comparison. Choice B divides the wrong way (20 ÷ 60).
Question 10 of 20 · Multiple Choice
In a flower test, some flowers were covered with fine mesh bags that let in light and air but kept insects out. What was the purpose of the bagged flowers?
Answer: A
The bagged flowers are a control: they show what happens without insect visits, so the class can tell how much the visitors add. Choice B is a different purpose that the test did not measure. Choice D is wrong because the bags keep insects out rather than trapping them.
Question 11 of 20 · Multiple Choice
A student claims: "Male birds with brighter feathers raise more young." Which finding would weaken this claim?
Answer: C
If bright and dull males in the same area raised the same number of young, the brightness made no difference to the outcome the claim is about. Choice B would support the claim. Choice D is about the people watching, not about reproduction.
Question 12 of 20 · Multiple Choice
Invented data: on a cold day, eggs in thick, well-built robin nests stayed 6 °C warmer while the parent was away than eggs in thin nests, and more of them hatched. Which conclusion do the data support?
Answer: D
The data compare nests and show warmer eggs and more hatching in thick nests, which supports a higher probability, not a certainty. Choice B says "every egg", which the data cannot show. Choices A and C make claims the data never tested.
Question 13 of 20 · Multiple Choice
A squirrel buried 60 acorns and dug up 45 of them by spring. What percent of the acorns were left in the ground?
Answer: A
60 - 45 = 15 acorns were left, and 15 ÷ 60 = 25%. Choice B is the percent the squirrel dug up. Choice C uses the count of 15 as a percent. Choice D divides 15 by 45 instead of by all 60 buried acorns.
Question 14 of 20 · Multiple Choice
Male crickets that chirp longer attract more females, but their sound also leads a parasite fly to them. Which statement uses both facts correctly?
Answer: B
The behavior has a benefit and a cost, so its overall effect on reproduction depends on which is larger. Choice A ignores the extra females. Choice D gives the crickets a purpose ("want"), which is not scientific reasoning about probability.
Question 15 of 20 · Short Answer
Killdeer parents sometimes pretend to have a broken wing to lead foxes away from the nest. In an invented study, 26 of 32 nests where a parent did the display raised chicks, and 9 of 18 nests where no display was seen raised chicks. Find both percents and write a claim with evidence.
26 ÷ 32 = 81.25% and 9 ÷ 18 = 50%, a difference of about 31 percentage points. Claim: the broken-wing display raises the probability that a killdeer raises chicks, because the fox follows the parent away from the eggs. A full answer notes that the groups are different sizes, so percents are compared.
Question 16 of 20 · Short Answer
Many flowers visited by hummingbirds are red, shaped like long tubes and full of nectar, but have little or no scent. Explain how each of these structures could raise the plant's probability of making seeds.
Red color: hummingbirds find flowers mainly by sight, so a bright red flower is easy for them to find. Tube shape: only an animal with a long beak reaches the nectar, and its head brushes the pollen on the way in. Nectar: rewards the bird so it keeps visiting flowers of this kind and carries pollen between them. Scent adds little because the birds rely on sight. Each point should end with more pollen moved and so more seeds.
Question 17 of 20 · Short Answer
Plan a fair test of the claim: "The scent of a flower attracts more bee visits." Name what you change, what you keep the same, what you count and how you make the result reliable.
Change only the scent: for example, paper flowers of the same color, size and sugar water, half with a drop of flower scent and half without. Keep the same: color, size, reward, place, time of day. Count: bee visits to each kind in the same amount of time. Reliable: many flowers of each kind, repeated on several days, positions swapped. Observe from a distance and do not touch the bees.
Question 18 of 20 · Short Answer
Invented data: 48 of 64 African buffalo calves that stayed in the middle of the herd survived their first year, and 9 of 24 calves that stayed at the edge survived. Find both percents and state what the data suggest about this behavior.
48 ÷ 64 = 75% and 9 ÷ 24 = 37.5%. Staying in the middle of the herd goes with a 37.5 percentage point higher survival, so the herding behavior raises the probability that calves live to reproduce. The edge group is smaller (24), so more data would make the evidence stronger.
Question 19 of 20 · Short Answer
Some forest ants carry violet seeds to their nests because each seed has a small, oily food body attached. The ants eat the food body and leave the seed in the rich soil of the nest. In an invented test, 26 of 40 carried seeds sprouted and 6 of 40 seeds left under the parent plant sprouted. Explain how the ants' behavior and the seed's structure work together.
26 ÷ 40 = 65% and 6 ÷ 40 = 15%. The food body is a plant structure that gets the ants to carry the seed. The ants' behavior moves the seed away from the parent and leaves it in soil good for germination. Together they raise the probability that the seed grows, by 50 percentage points in these data.
Question 20 of 20 · Short Answer
A student writes: "Peacocks grow long, colorful tails because they want to attract females." Rewrite the sentence as scientific reasoning, and say what evidence would support it.
Better: "Males with longer, more colorful tails have a higher probability of mating, so they leave more offspring." The bird does not choose its feathers; the reasoning is about chances, not wants. Evidence: compare mating success of males with more and fewer eyespots in the same group, using percents.
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does MS-LS1-4 mean?
MS-LS1-4 asks students to use evidence to argue how animal behaviors and plant structures change the chance that animals and plants reproduce successfully. Students compare data, such as how many chicks survive with and without a behavior, and explain why. The code means Middle School, Life Science, core idea 1 (From Molecules to Organisms: Structures and Processes), performance expectation 4.
What grade is MS-LS1-4 taught in?
It is a middle school standard for grades 6-8, and schools place it in grade 6, 7 or 8 life science. It fits well in a unit on reproduction or plant and animal life cycles, often next to MS-LS1-5 on growth.
Does MS-LS1-4 have an assessment boundary?
No. The official page lists no Assessment Boundary for MS-LS1-4. The Clarification Statement gives the examples: nest building, herding, calls and colorful feathers for animals; animals moving pollen or seeds and helping seeds sprout; and bright flowers, nectar, scent and hard nut shells for plants.
What is the difference between a behavior and a structure?
A behavior is something an animal does, like building a nest or singing. A structure is a body part, like a petal, a nectar gland or a nut shell. The standard pairs animal behaviors with plant structures, and it also includes animal behaviors that help plants, such as a squirrel burying nuts.
What does "probability of successful reproduction" mean for students?
It means the chance that an organism leaves offspring that grow up and reproduce too. A behavior or structure rarely guarantees anything; it raises or lowers that chance. That is why the evidence is a comparison of percentages between two groups, not a single story.
How do students write an argument for MS-LS1-4?
Use claim, evidence and reasoning. The claim names the behavior or structure and its effect. The evidence gives numbers from two groups, as percents. The reasoning explains how the behavior or structure changes the chance of offspring, for example "feathers trap warmth, so eggs stay warm enough to develop".
Why compare percents instead of counts?
Because groups are often different sizes. Thirty eggs hatching sounds better than twenty, but not if the first group had 100 eggs and the second had 25. Turning each count into a percent of its group makes the comparison fair.
Can students do MS-LS1-4 labs without live animals?
Yes. Flower dissections, seed tests, models like the squirrel cache game and data from published-style studies cover the standard well. If students observe insects or birds outdoors, they watch from a distance and never catch or handle them. Students with bee or pollen allergies can record data indoors.
How does MS-LS1-4 connect to natural selection?
It lays the groundwork. MS-LS1-4 shows that a behavior or structure can change an individual's chance of reproducing. In MS-LS4-4, students explain how inherited differences in traits change those chances, so the traits become more common over generations.
What mistakes do students make with this standard?
A frequent one is saying that animals or plants act "because they want to" or "to help the species". Another is treating one story as proof, or comparing counts from groups of different sizes. Ask students to name the two groups, give both percents and use words like "raises the chance".
07
Related Standards
6 standards
These standards connect to MS-LS1-4: 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 internal and external structures support survival and reproduction
Lesson coming soon
3-LS2-1Prerequisite
Argue that some animals form groups that help members survive
Lesson coming soon
Alongside
MS-LS2-2Parallel
Explain patterns of interactions among organisms across ecosystems
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