Year 10 Science · Unit 1 · Lesson 6

Selective Breeding

Foundation Worksheet

Name

Date

Class

Learning Goals

Recall the key vocabulary of selective breeding and artificial selection
Explain how breeders choose individuals to produce desired traits over generations
Match real selective breeding examples to the trait and organism involved

Warm Up

Fill the gap

Choose the correct word from the word bank to complete each sentence. Not all words are used.

selective breeding artificial trait generations diversity inbreeding Merino mutation transgenic

When humans choose which individuals will breed so that offspring inherit a desired characteristic, the process is called . Because humans, rather than the environment, apply the selection pressure, it is also known as selection. A breeder first identifies individuals that show the wanted , then breeds them together repeatedly over many until the characteristic becomes common in the population. Australia's sheep were selectively bred to produce some of the world's finest wool. A drawback of this process is that it reduces genetic in a population, and breeding closely related individuals can cause depression, which increases the risk of disease.

Your Turn

Match each term to its definition

Draw a line connecting each selectively bred organism on the left to the desired trait it was bred for. Or write the matching letter next to each organism.

Organism	Your answer	Desired trait it was bred for
Merino sheep		A. Larger grain size and higher yield to feed more people
Holstein cattle		B. Fine, soft, high-quality wool
Corn (maize)		C. High milk production
Border collie		D. Drought resistance and higher yield in dry conditions
Drought-tolerant wheat		E. Herding instinct and trainability for working livestock
Angus cattle		F. High-quality beef and good meat marbling

Show What You Know

1. Explain why selective breeding usually takes many generations to produce an organism with a strongly expressed desired trait.

Recall 2 marks

2. Selective breeding reduces the genetic diversity of a population. State one reason why low genetic diversity can be a problem for a breed or crop.

Recall 2 marks

Wrap Up

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