Variation — Science definition

Defined in 2 courses:

Where it is taught

In use

First, the individuals in a population are not identical — they show variation in traits like size, speed, color, and biochemistry, and much of that variation is heritable, meaning it can be passed to offspring through genes.

Natural Selection

Questions using variation

Problem 1

Which statement correctly uses variation in Weather & Climate: Time Scales and Comparisons?
  1. A single weather event proves or disproves a whole long-term climate trend.
  2. variation: Differences among observations that a single average may not describe.
  3. Equal average temperatures mean identical daily conditions.
  4. One illustrative result establishes every real condition and needs no further evidence.
Answer and explanation

variation: Differences among observations that a single average may not describe.

Differences among observations that a single average may not describe. The supplied summaries rise by 0.8 °C from first to last. They describe a regional seasonal pattern across the stated periods, not tomorrow’s temperature. The numbers alone do not identify the cause or describe every location, and daily variation remains within each period.

Problem 2

What is the ultimate source of the new heritable variation that natural selection acts upon?
  1. An organism's conscious effort to change
  2. The environment directly rewriting an organism's genes as needed
  3. Mutation (with reshuffling of genes in sexual reproduction)
  4. Traits organisms build up through exercise and practice
Answer and explanation

Mutation (with reshuffling of genes in sexual reproduction)

New alleles arise from random mutation; sexual reproduction then reshuffles this variation. Natural selection can only act on variation that already exists.

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