Selective breeding and human food security | Combined science

Starter quiz

Why are there no fossils younger than 10 000 years?

No animals or plants have died in the right conditions for fossilisation.

Only dinosaurs left fossils.

There are gaps in the fossil record.

The process of fossilisation takes thousands of years. ✓
Match the words to their meaning.

fossil record

⇔

All the fossils ever found. ✓

extinct

⇔

A species which has no living individuals remaining anywhere. ✓

evolution

⇔

Changes in the characteristics of a species over many generations. ✓

Common ancestor

⇔

An ancestor species shared by several other species. ✓

transitional species

⇔

A species with characteristics between an ancestor and a later species ✓
Which layer of sedimentary rock will contain the youngest fossils?

'a' ✓
Scientists think *Archeopteryx* and modern birds share a common ancestor, but there is a gap in the fossil record. Why are there gaps in the fossil record?

All plants and animals form fossils.

Not all fossils have yet been discovered. ✓

Scientists don’t know what the fossils look like.

Many fossils rot away leaving no trace.
Which species is the common ancestor?

'A' ✓
The diagram shows a suggestion for the evolution of the hippopotamus and some modern whales. Which statement is correct?

Whales evolved from the hippopotamus.

The hippopotamus evolved from whales.

Whales and the hippopotamus are not related.

Whales and the hippopotamus share a common ancestor. ✓

Exit quiz

True or false? Selective breeding is when humans choose which individuals to breed based on their characteristics.

True ✓

False
Put the steps in the correct order to describe the process of selective breeding.

1

⇔

Select two individuals with the desired characteristic.

2

⇔

Breed them together.

3

⇔

From the offspring produced, choose individuals with the desired characteristic.

4

⇔

Breed these offspring together.

5

⇔

Repeat for many generations.
Food security is a measure of the quality and quantity of food available to humans. Why is this increasingly important globally?

Humans are fussy eaters.

The human population is continuously increasing. ✓

There are thousands of edible plants and animals.

In the UK there is an increase in obesity.
Although there are thousands of edible plants worldwide, farmers and plant breeders have selectively bred only a few of these. Most of our energy comes from just three plants: corn, wheat and ______.

'rice' ✓
During the green revolution, Norman Borlaug produced modern wheat crop plants by breeding which two varieties of wheat?

Dwarf thin stemmed with tall small grained.

Dwarf thin stemmed with tall big grained.

Dwarf thick stemmed with tall small grained.

Dwarf thick stemmed with tall big grained. ✓
There are many desirable characteristics that selective breeders have looked for to produce better crop plants for food. Which is not one of these desirable characteristics?

crop mass

disease resistance

pleasing appearance ✓

taste

Worksheet

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Lesson Details

Key learning points

Some plants and animals have features that are useful to us (e.g. they can provide food and materials, or do work).
Selective breeding by humans causes particular features to become more (or less) common in the species.
After many generations, the resulting domesticated species can be quite different to their wild ancestors.
Examples of the selective breeding of a farm animal and a crop from their wild ancestors.
The dependence of humans on domesticated animals and crops for food security.

Common misconception

Students often forget that selective breeding is a process that happens over many generations.

This lesson includes examples of how to describe the process of selective breeding.

Keywords

Selective breeding - The process in which humans choose individuals with desirable traits and mate them in order to make offspring with these desirable traits.
Crop - Plants grown on a large scale for food or profit.
Domesticated - An animal that has been tamed and is kept as a pet or on a farm.
Farm animal - Animals that are kept on farms for food or work.
Food security - A measure of the quantity and quality of food available to support households or whole communities.