HS-LS4-5: How Environmental Change Shapes Species
Also called NGSS HS-LS4-5 · Topic: Natural Selection and Evolution · Life Science
The Official Wording
Evaluate the evidence supporting claims that changes in environmental conditions may result in (1) increases in the number of individuals of some species, (2) the emergence of new species over time, and (3) the extinction of other species.
Clarification statement: Emphasis is on determining cause and effect relationships for how changes to the environment such as deforestation, fishing, application of fertilizers, drought, flood, and the rate of change of the environment affect distribution or disappearance of traits in species.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What HS-LS4-5 Means in Plain English
Students judge evidence that a change in the environment can help some species grow in number, lead over time to new species, and push others to extinction. They trace cause and effect for changes like logging, drought, floods, fishing or fertilizer runoff.
The speed of change matters as much as its size: slow change gives populations time to adapt, while fast change can outpace them. It builds on HS-LS4-4 and HS-LS2-6 and links to human impacts in HS-ESS3-1 and HS-LS2-7.
HS-LS4-5 I Can Statements
- I can explain how environmental change helps some species and harms others.
- I can describe how a barrier can lead to new species.
- I can judge whether evidence supports a cause and effect claim.
HS-LS4-5 Worked Example
A checkerboard model of a forest that loses patches to clearing, tracking a forest-interior bird and an edge-loving mammal.
As a forest is cleared in patches, which species gain habitat and which lose it?
Set It Up: A 10 by 10 checkerboard of green paper squares for forest, a list of random square coordinates and a tally sheet.
- Count interior squares, with forest on all four sides, and edge squares, touching a cleared square or the border.Before clearing: 64 interior, 36 edge
- Clear 10 squares from the random list and recount.After: 30 interior, 60 edge
- Clear 10 more squares and count again.After: 12 interior, 68 edge
- Estimate populations with one ovenbird pair per 4 interior squares and one deer per 3 edge squares.Ovenbird pairs: 16, 7, 3. Deer: 12, 20, 22
- Compare the trends and discuss what happens if the last interior patches vanish.Ovenbirds near local extinction
Clearing a fifth of the forest cut interior habitat by more than 80% while edge habitat nearly doubled, so the interior bird crashed as the deer increased.
Why it works: Each species depends on particular conditions, so the same change shrinks habitat for interior specialists like ovenbirds while expanding it for edge species like white-tailed deer.
Common Mistakes with HS-LS4-5
Thinking change only hurts species
“Cutting forests is bad for all animals”
Try this: Ask which species gain and which lose, since a change that destroys one habitat often creates another that some species thrive in.
Expecting species to adapt to anything
“They will just evolve to survive”
Try this: Adaptation needs existing variation and many generations, so species with long lives or few offspring can vanish when change is fast.
Correlation taken as cause
“Deer rose while birds fell, so deer killed the birds”
Try this: Look for a mechanism and other explanations, such as habitat loss affecting both species, before claiming one change caused another.
Where HS-LS4-5 Fits
Practice HS-LS4-5
Quick Check
- A river shifts course and splits a beetle population for thousands of years. What could happen?
- Why can rapid change cause more extinctions than slow change?
- Give an example of an environmental change that helps a species increase.