8.evolution and genetic engineering

Evolution and Genetic Engineering

Environmental impact on phenotype

Environmental impact on phenotype

An organism’s final appearance (phenotype) is the result of the interaction between it’s genotype and the environment it develops in.

This can be shown as a word equation:

genotype + environment = phenotype

Environmental impact on phenotype

Studies to investigate the effect of different environmental factors on phenotype are carried out using identical twins (human) or clones (plants)

Why?

Environmental impact on phenotype

Notes

genotype + environment = phenotype

To investigate the impact of environmental factors on phenotype, scientists can conduct twin, or clone, studies. Because the twins are genetically identical, any differences in phenotype must be due to environment.

Environmental impact on phenotype

Notes:Give an example of how environment

can influence the phenotype of human identical twins during growth

Give an example of how environment can influence the phenotype of humans after growth is complete.

Environmental impact on phenotype

Think!

Will the effects of these environmental factors be passed onto the organisms offspring?

Why / why not?

Environmental impact on phenotype

NoteDifferences in phenotype caused by

environmental factors (‘acquired characteristics’) are not passed down from one generation to the next.

Acquired characteristics therefore have little evolutionary significance, as they play no part in natural selection.

Evolution and Genetic Engineering

Natural selection

Natural Selection

Think!

Does every organism get a chance to pass on it’s genes?

Why / why not?What could this have to do with

evolution?

Natural Selection Notes

Natural selection is the process by which organisms that are better adapted to their environment survive and breed, while those less well adapted fail to do so.

So the better adapted organisms are more likely to pass their characteristics to the next generations.

The Peppered Moth

Watch this video

Now collect the cut-out of ‘The Peppered Moth Story’, and stick it – in the correct order – in your notes

Natural Selection Summary

Sexually reproducing organisms show genetic variety

Some organisms are better adapted to their surroundings than others

This allows them to survive and pass on these favourable genes – natural selection

Over time, natural selection can result in the creation of new species - evolution

Evolution and Genetic Engineering

Selective Breeding

Selective Breeding

People rely on plants and animals to supply us with many of the things we need.

Can you think of some examples?

Selective Breeding

All of the species of plants and animals that we eat or use today are derived from wild ancestors

However, some look very different. Have a look at the cows on the next slide…

Selective Breeding

‘Wild’ cow ‘Beef’ cow

What differences can you see?

Selective Breeding Note

Selective breeding is the selection of individuals which possess desirable characteristics and breeding them to produce the next generation.

Selective Breeding Notes

Answer Q1+2 in Tp204 in sentences

Think!What do you think are some of the problems

/ limitations of selective breeding?

Selective Breeding Notes

Collect the table ‘Problems in Selective Breeding’ and use the green booklet (8.4, page 3) to complete it.

Evolution and Genetic Engineering

Genetic Engineering

Genetic Engineering Notes

Another method of artificial selection is genetic engineering

Genetic engineering is the transfer of DNA from one type of organism to a different organism

Genetic Engineering

Bacterial cell

Genetic Engineering Notes

Collect a ‘Genetic Engineering’ diagramUse Torrance p206 to fill in the missing

information and stick into your notes.

Then attempt Tp207 Q3(b)

Advantages and Disadvantages of Genetic Engineering

Using the information in the green booklet 8.5 page 2+3, draw a table like the one below and complete it with 5 advantages and 3 disadvantages of genetic engineering

Advantages of genetic engineering

Disadvantages of genetic engineering

Advantages of genetic engineering

Disadvantages of genetic engineering

1. Completely different species can be combined

2. Organism shows only the desired characteristic

3. Large quantities can be produced

4. Easier to purify product

5. Faster than selective breeding

1. Bacteria can’t produce complex proteins

2. Difficult to insert genes without damaging host cell

3. Might produce harmful by-products

4. Possible release of GM organisms into environment

5. Expensive

Genetic Engineering Vs Selective Breeding

Genetic engineering and selective breeding are two methods by which scientists can alter the genotype of another species for the benefit of humankind.

On the flipchart paper, compare the two methods.

Genetic Engineering Debate

You are now going to look at some of the arguments surrounding the use of genetic engineering.

Collect the sheet of statements and cut them out

Use the statements to produce a table as shown on Tp213

Uses of Genetic Engineering

Think!What was being produced using genetic

engineering in the video?Where was this originally obtained?What do you think the benefits are of the

genetically engineered product over that of the original source?

Uses of Genetic Engineering

Use the information on Tp207-211 to answer Tp211 ‘Testing your Knowledge’ in sentences