Selective breeding

Plants of the same species but distinctly different characteristics are called…

Varieties

Animals of the same species but distinctly different characteristics are called…

Breeds

Describe the process of traditional selective breeding in plants.

1. In a lab, pollen with a desired characteristic is taken from one plant and transferred using a paint brush onto another plant with a desired characteristic

2. Their seeds are grown and the best individual seeds are selected and bred the following year

3. This continues for several generations until the desired plant is obtained

What are some strains that crop plants are selectively bred for?

• Give higher yield

• Are resistant to certain diseases

• Are resistant to herbicides or pesticides

• Are hardier - ability to survive in harsher climates or are productive for longer periods of the year

How can improved yield be produced?

• Improving taste and colour of the crop

• Improved growth in adverse conditions e.g.cold and drought

• Improve pest and disease resistance

• Decreasing the size of the plant we do not eat

What is the problem with selective breeding?

It can lead to inbreeding depression due to the reduction in genetic diversity, leading to accumulation of harmful alleles and so a decrease in fertility

What are some reasons for selective breeding in animals?

• Produce more products like meat, milk, eggs

• Produce more offspring

• Produce more fur

• Produce better quality fur

• Show increased resistance to diseases and parasites

List 5 features that farmers have bred sheep for

1. Increased growth and muscle formation

2. Increased milk production

3. Softer, longer wool

4. Resistance to disease

5. Docility (quiet/ calm)

Features chickens are selective bred for

• meat production

• larger eggs

• more eggs

• faster growth

Features horses are selective bred for

• transport

• racing

• carrying loads

• hooves for glue

Features dogs are selective bred for

• guard dogs

• hunting

• herding sheep

• sniffer (police dogs)

• guide dogs

• companionship

Features cats are selective bred for

• appearance

• companionship

• pest removal (mice)

Features fish are selective bred for

• food source

• display in fish tanks