Year 10 Science · Unit 1 · Lesson 1

Introduction to Genetics and Heredity

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Learning Goals

Compare two

Complete the table to compare inherited traits with acquired characteristics.

FeatureInherited TraitAcquired Characteristic
Definition
Is it encoded in DNA?
Can it be passed to offspring?
One example
One Australian example from the lesson

Real-world context

Australian Merino sheep are famous for their fine wool. In the early 1800s, grazier John Macarthur imported Spanish Merinos and chose which animals bred together, selecting only those with the finest fleece year after year. Today, Australian Merinos produce wool as fine as 15 microns, roughly one-fifth the thickness of a human hair. Meanwhile, a sheep's wool length can also be affected by its diet and health during a season: poor nutrition produces a weak, thin section of fibre (a "break" in the wool), but this environmental effect does not change the animal's genes or affect its offspring's fleece potential.

(a) Is wool fineness (fibre diameter) an inherited trait or an acquired characteristic? Explain your reasoning using the terms gene, allele, and heredity.

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(b) A farmer notices that one season her Merino flock has thinner wool than usual because of drought stress reducing feed quality. Will this affect the fleece of the sheep's offspring? Explain why or why not.

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(c) Even within the same Merino flock, individual sheep vary in wool fineness. Using the terms variation and allele, explain why offspring from the same parents can have slightly different fleece qualities.

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Wrap Up

In one sentence, what was the main idea of this lesson?