Inherited Traits, Environment & Mutation — Practice · Grade 7 Science

Chapter: Genes, Cell Division & Heredity

What this practice covers

By the end of Inherited Traits, Environment & Mutation you should be able to:

8 questions, written answer and multiple choice, each with a worked explanation.

Vocabulary used: mutation, inherited trait, environmental influence, acquired characteristic, transmission.

Problem 1

Does a height difference prove a genetic difference?
Answer and explanation

No. Resources and other environmental conditions can also affect height.

Problem 2

Why is “a seedling mutated because it wanted more light” incorrect?
Answer and explanation

It gives intention to mutation. Changes arise through biological processes; their consequences depend on conditions.

Problem 3

Does every body-cell mutation pass to offspring?
Answer and explanation

No. Transmission depends on contribution to reproductive genetic material, not simply occurrence anywhere in a body.

Problem 4

Is learning the same skill from a parent proof of a new inherited allele?
Answer and explanation

No. Teaching and experience can transmit a skill through learning; that is not evidence of a specific genetic change.

Problem 5

Illustrative identical-genotype seedlings: one group receives adequate light and averages 8 cm; another receives low light and averages 5 cm. No sequence change is recorded. Explain the supported environmental comparison and correct a claim that every shorter plant must have acquired a heritable mutation.
Answer and explanation

The supplied record supports an environmental growth comparison, with a 3 cm mean difference under the stated light conditions. It does not document a sequence change or heritable mutation. Actual causal interpretation still depends on the fairness of the comparison and variation. A trait difference alone cannot establish mutation or transmission to offspring.

Calculate the observed 3 cm mean difference.

Use the stated equal-genotype information.

Separate environmental response from undocumented mutation and transmission.

Response criteria

  • Explain the relevant biological process accurately.
  • Use the supplied evidence and show calculation steps with units where needed.
  • Connect a labeled model or mechanism with the claim.
  • State an assumption, evidence limitation, or useful next observation.

Problem 6

A mutation has no visible effect in one setting. Must it be impossible or meaningless?
Answer and explanation

No. Its effect may be small, depend on conditions, or not change the measured trait. A genetic change and a visible phenotype are different observations.

Response criteria

  • Explain the relevant biological process accurately.
  • Use the supplied evidence and show calculation steps with units where needed.
  • Connect a labeled model or mechanism with the claim.
  • State an assumption, evidence limitation, or useful next observation.

Problem 7

Which statement fits the model?
  1. All mutations help
  2. Mutations can have different effects depending on context
  3. Learning a skill proves an allele change
  4. Every body mutation enters gametes
Answer and explanation

Mutations can have different effects depending on context

Effects and transmission depend on the change and conditions.

Problem 8

Give one additional observation needed to claim a new variant was inherited.
Answer and explanation

Evidence of the genetic change in reproductive material or offspring, with a suitable comparison, is needed beyond one parent’s visible change.

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