Download Variation, Genetics and Evolution

Wellsway school science dept.
Curriculum 2011 – AQA Science
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Biology workbook
Wellsway school science dept.
Curriculum 2011 – AQA Science
Biology workbook
Why individuals of the same species are different from each other, and the new methods we
have for producing plants and animals with the characteristics we prefer.
There are not only differences between different species of plants and animals but also
between individuals of the same species. These differences are due partly to the information in
the cells they have inherited from their parents and partly to the different environments in which
the individuals live and grow. Asexual reproduction can be used to produce individuals exactly
like their parents. Scientists can now add, remove or change genes to produce the plants and
animals they want.
Candidates should use their skills, knowledge and understanding to:
interpret information about cloning techniques and genetic engineering techniques
make informed judgements about the economic, social and ethical issues concerning cloning and
genetic engineering, including GM crops.
Subject content - Why organisms are different.
a) The information that results in plants and animals having similar characteristics to their parents is
carried by genes which are passed on in the sex cells (gametes) from which the offspring develop.
b) The nucleus of a cell contains chromosomes. Chromosomes carry genes that control the
characteristics of the body.
c) Different genes control the development of different characteristics of an organism.
d) Differences in the characteristics of different individuals of the same kind may be due to
differences in:
• the genes they have inherited (genetic causes)
• the conditions in which they have developed (environmental causes) or a combination of
both.
Reproduction
a) There are two forms of reproduction:
• sexual reproduction – the joining (fusion) of male and females gametes. The mixture of the
genetic information from two parents leads to variety in the
offspring
• asexual reproduction – no fusion of gametes and only one individual is needed as the parent.
There is no mixing of genetic information and so no variation in the offspring. These
genetically identical individuals are known as clones.
b) New plants can be produced quickly and cheaply by taking cuttings from older plants. These new
plants are genetically identical to the parent plant.
c) Modern cloning techniques include:
• tissue culture – using small groups of cells from part of a plant
• embryo transplants – splitting apart cells from a developing animal embryo before they
become specialised, then transplanting the identical embryos into host mothers
• adult cell cloning.
d) In genetic engineering, genes from the chromosomes of humans and other organisms can be „cut
out‟ using enzymes and transferred to cells of other organisms.
e) Genes can also be transferred to the cells of animals, plants or microorganisms at an early stage
in their development so that they develop with desired characteristics.
1.
Revise with your teacher the basic structure and functions of animal and plant cells. Label
the diagrams overleaf.
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Wellsway school science dept.
Curriculum 2011 – AQA Science
ANIMAL CELL
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Biology workbook
PLANT CELL
What is the function of the nucleus in:
a. plant cells
b. animal cells
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Discuss with your teacher the relationship between the nucleus, chromosomes, genes
and DNA.
Using labelled diagrams show this relationship in the space below & overleaf.
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Wellsway school science dept.
Curriculum 2011 – AQA Science
Biology workbook
If you have finished…. find out how DNA’s genetic code leads to the production of an
organisms inherited characteristics.
4.
Comparing sexual & asexual reproduction.
Read your textbook or support material on sexual & asexual reproduction.
Explain briefly each of the following terms:
a. gamete
b. fertilisation
c. embryo
d. genetic variation
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Wellsway school science dept.
Curriculum 2011 – AQA Science
e. meiosis
f. mitosis
g. genetically identical
h. clone
i. mutation
j. characteristic
k. Ionising radiation
l. Mutagenic.
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Wellsway school science dept.
5.
Curriculum 2011 – AQA Science
Biology workbook
Complete the table comparing the features of sexual & asexual reproduction.
Feature
Sexual reproduction
Asexual Reproduction
Number of parents
Are sex cells produced?
Does fertilisation take
place?
Type of cell division
Genes in offspring
Variation in offspring
Advantages
Disadvantage
Examples
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6.
Curriculum 2011 – AQA Science
Biology workbook
Watch the video, MSS presentation or PowerPoint on asexual reproduction & cloning.
Read your textbook or support material on asexual reproduction & cloning.
Discuss with your teacher the meaning of the terms: asexual reproduction, and cloning.
Revise mitosis, to remind yourself about how clones are produced.
Answer the questions below:
(a) Define the term asexual reproduction:
(b) Define the term “cloning”:
(c) Farmers & gardeners have been “cloning” for many centuries. Give 3 examples of
traditional cloning techniques:
(i)
(ii)
(iii)
(d) What are the advantages of cloning? (Both traditional and modern)?:
(e) Modern cloning includes tissue culture. Describe clearly, using words & diagrams, how
tissue culture works:
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Wellsway school science dept.
Curriculum 2011 – AQA Science
Biology workbook
(f) Read the information on Embryo cloning. Explain the meaning of each these terms:
(i) Artificial Insemination:
(ii) In Vitro Fertilisation (IVF):
(iii) Embryo:
(iv) Surrogate (mother):
(g) Draw a clearly labelled diagram summarising the main stages of embryo cloning.
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Curriculum 2011 – AQA Science
Biology workbook
(h) Read the information about Adult Cell Cloning (Nuclear Transfer), & answer the
questions which follow:
Adult Cell Cloning (Nuclear transfer) is a two-part process:
•
•
•
firstly, scientists remove the nucleus from an unfertilised egg cell,
secondly, they replace it with the nucleus of an older donor cell.
A new clone—a genetically identical copy of the donor—forms when the egg starts to
divide by mitosis.
(i) Why is it necessary to remove the nucleus from the unfertilised egg cell?
(ii) Which “parent” – the one which supplied the unfertilised egg, or the one which supplied
the donor nucleus – will the new individual be identical to? Explain your answer:
(iii) Suggest one advantage of producing animal clones by nuclear transfer.
7.
Watch the video, MSS presentation or PowerPoint on Genetic Engineering (Artificial Gene
Transfer).
Read your textbook or support material on Genetic Engineering.
Discuss with your teacher the processes involved in Genetic Engineering.
(a) Read the sentences below on production of human insulin by Genetic Engineering. They
are not in the correct order. Re-arrange them so that they are in the correct sequence.
(rewrite them in the correct sequence in the space below if you wish):
Genetic engineering means removing a gene from one living organism and putting it
into another. This is how it has been used to help diabetics:
1. The bacterium makes insulin.
2. Special enzymes are used as chemical scissors. These cut out the insulinmaking gene from the rest of the DNA.
3. The bacteria multiply very rapidly.
4. The plasmid is put into a bacterium.
5. The human gene that codes for the production of insulin is identified.
6. All the bacteria produced will have the insulin gene. Lots of insulin will be
made.
7. The human insulin-making gene is put into the plasmid.
8. A circular piece of DNA called a plasmid is removed from a bacterium.
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Curriculum 2011 – AQA Science
Biology workbook
(b) Fill in the gaps in the following passage:
Many inherited diseases are caused when the body cannot make a particular
____________. For instance, people with haemophilia cannot make the protein
factor 8, which helps ___________ to clot. Diabetics cannot make the protein
____________. Genetic engineering makes it possible to make insulin quickly
and cheaply on a _________ scale. The _________________ are grown
inside huge industrial ____________________ called bioreactors. The
microbes grow quickly under ideal conditions. Each bacterium is an identical
______________ ____________ with a copy of the insulin-making gene. The
insulin is extracted and purified.
Before genetic engineering, diabetics had to use insulin that had been
extracted from __________ or pigs. This often produced reactions since it was
different from ____________ insulin.
Genetic engineering has also made it possible to produce large amounts of
safer __________ much more quickly.
WORD LIST: bacteria
human
blood
insulin
drugs
large
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fermenters
protein
genetic clone
sheep
Wellsway school science dept.
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Curriculum 2011 – AQA Science
Biology workbook
Watch the video, MSS presentation or PowerPoint on Genetically Modified (GM) Crops.
Read your textbook or support material on GM Crops.
Discuss with your teacher the issues surrounding GM crop technology.
Complete the table below to summarise the main advantages and drawbacks of GM crops:
BENEFITS of GM crop technology
1.
CONCERNS about GM crop technology
1.
2.
2.
3.
3.
4.
4.
5.
5.
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Wellsway school science dept.
Curriculum 2011 – AQA Science
Biology workbook
Why some species of plants and animals have died out, and how new species of
plants and animals develop
Changes in the environment of plants and animals may cause them to die out.
Particular genes or accidental changes in the genes of plants or animals may give them
characteristics which enable them to survive better. Over time this may result in entirely new species.
There are different theories of evolution. Darwin’s theory is the most widely accepted.
Candidates should use their skills, knowledge and understanding to:
• interpret evidence relating to evolutionary theory
• suggest reasons why Darwin’s theory of natural selection was only gradually accepted
• identify the differences between Darwin’s theory of evolution and conflicting theories, such as
that of Lamarck
• suggest reasons for the different theories.
Subject knowledge - Evolution
a) The theory of evolution states that all species of living things have evolved from simple life-forms
which first developed more than three billion years ago.
b) Studying the similarities and differences between organisms allows us to classify living organisms
into animals, plants and microorganisms, and helps us to understand evolutionary and ecological
relationships.
c) Evolution occurs via natural selection:
• individual organisms within a particular species may show a wide range of variation because
of differences in their genes
• individuals with characteristics most suited to the environment are more likely to survive to
breed successfully
• the genes which have enabled these individuals to survive are then passed on to the next
generation.
d) Where new forms of a gene result from mutation there may be more rapid change in a species.
1.
Watch the video on Evolution (B39), and whilst doing so answer the following questions.
a. What does the theory of evolution state?
b. What adaptations do the following animals have which improve their chances of survival in
their environment?
Snowshoe hare and Lynx:
Tiger:
Horses:
Cheetah:
c. What evidence exists to show us change in life over time?
d. What evidence is there to suggest that all mammals have a common ancestor?
e. What is natural selection?
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Wellsway school science dept.
Curriculum 2011 – AQA Science
Biology workbook
f. What do mutations introduce into a population?
g. What do fossils / bones show us about life on Earth?
2.
You will be given a piece of coloured card by your teacher to use as a background for this
exercise. You will also be given a number of smaller different coloured pieces of card.
Place these fairly evenly spread but in random order on the background card.
Get a partner to as quickly as possible pick up 30 pieces of the smaller card one at a time.
Record the number of each colour they picked up.
Suggest a reason for the results.
Do you think this is a good model for illustrating the effect of camouflage colouring in
predator prey relationships? Try to think of positive and negative reasons!
3.
Using the internet find out about Charles Darwin, and produce an A4 poster answering the
following questions:
What did he look like?
When was he alive?
Where did he live?
What ideas did he have?
Where did he travel?
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Wellsway school science dept.
4.
Curriculum 2011 – AQA Science
Biology workbook
During Darwin’s travels he made very important observations about populations of
organisms. These are as follows:
1. Organisms produce more offspring than are needed to replace the parents.
2. Natural populations tend to remain stable over a long period of time.
3. There is variation amongst individuals of a given species.
He used those observations to make some deductions that helped him come up with the
theory of evolution. See how you do by answering the following!
a) How many offspring need to survive per generation to maintain a population?
b) For a population to stay stable what must happen to most of those organisms?
Okay, so now you’ve realised that there is a struggle for survival.
c) Why do some organisms survive and others die (try to give an example to help explain)?
Most wild rabbits in the UK are of the agouti (brown) colour. However some will be born with
white fur.
d) What causes the rabbit’s fur colour?
e) Why do the agouti coloured rabbits survive better?
Let’s consider a scenario. Humans decide not to protect the environment. We decide to drive
big cars, waste energy in the homes, don’t recycle paper, and keep replacing perfectly good
mobiles, never re using plastic bags etc – all leading to emissions of green house gases.
This causes melting of the polar caps, a cooling of the Gulf stream and a decline in
temperature of the UK.
f) Explain how the rabbit population might change over time.
g) Why do you think that many people do not agree with Charles Darwin’s theory of
evolution?
5.
Natural Selection in Peppered moths.
Read B4U, pg 301, then answer question 11 pg 326.
a) i)
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Wellsway school science dept.
Curriculum 2011 – AQA Science
Biology workbook
a) ii)
a) iii)
b)
c)
6.
Is evolution still occurring?
Warfarin is a poison used to kill rats. This chemical control method worked well until the
1960’s when some rats developed a resistance to the poison due to a mutation.
a) What is a mutation?
b) This has been called a ‘selective advantage’. What do you think this means?
c) What do you think will happen to the rat population if Warfarin continues to be used?
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Wellsway school science dept.
7.
Curriculum 2011 – AQA Science
Biology workbook
Fill in the gaps to help test your understanding. Use the following words to help
Change, Darwin, deeper, environment, , evolution, extinct, fossils, genes, natural selection,
The theory of evolution tries to explain the ___________ in life that has ever existed on earth
throughout time. Much of this evidence comes from ______________. Older fossils are
found in the _______________ layers of rocks in places like the Grand Canyon. Those
fossils found lower down are from organisms with less complex structures.
Charles _____________was the scientist who proposed a mechanism for the process of
____________ in his book the Origin of species.
Organisms that are best suited to their ______________________ will survive and breed.
When they breed they pass on their useful ____________ to the next generation. Since it is
‘nature’ that determines the best characteristic this process is known as _____________
_______________. Therefore evolution happens via natural selection.
If there is a change in the environment that a species does not adapt to deal with it may
become ______________. This may occur due to the presence of disease, new predators,
or climate change.
Well done! You have now completed the Variation, Genetics & Evolution topic.
Useful web links.
http://www.bbc.co.uk/schools/gcsebitesize/biology/variationandinheritance/4cloningandgenengrev5.shtml
http://www.s-cool.co.uk/topic_quicklearn.asp?subject_id=17&Topic_ID=13&Quicklearn_ID=4&loc=ql
www.defra.gov.uk/environment/gm1fse;
www.nature.com
www.gmsciencedebate.org.uk
www.gmnation.org.uk
www.wellcome.ac.uk/labnotes
(number 2)
http://www.pnas.org/misc/classics4.shtml
GM Animals
www.royalsoc.ac.uk/scienceinsociety
www.royalsoc.ac.uk/policy/index.html
www.hse.gov.uk/foi/openacgm.htm
www.bbc.co.uk/genes
http://www.bbc.co.uk/schools/gcsebitesize/biology/variationandinheritance/
http://www.biotopics.co.uk/genes/varn.html
http://www.s-cool.co.uk/topic_principles.asp?loc=pr&topic_id=10&subject_id=17&ebt=70&ebn=&ebs=&ebl=&elc=4
http://octopus.gma.org/surfing/antarctica/penguin.html
http://users.rcn.com/jkimball.ma.ultranet/Biologv Pages/E/Evolution .html
www.naturedetectives.org.uk
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Wellsway school science dept.
Curriculum 2011 – AQA Science
Biology workbook
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Glossary - Variation. (Muddled – sort them out!)
Asexual reproduction
Genetically identical offspring, produced by mitosis
Characteristic
Variation with only a few discrete categories e.g. eye colour
Clone
Reproduction involving only 1 parent, producing clones
Continuous variation
Variation with many different categories e.g. human height
Discontinuous variation
An observable feature, caused by genes, environment or both
Embryo
Joining together of male and female sex cells (gametes)
Fertilisation
Variation caused by changes in DNA in genes
Gamete
Individuals with exactly the same genes i.e. clones
Genetically identical
Early stage in development of an animal or plant
Genetic variation
Sex cell, male or female, e.g. egg, sperm, pollen
Ionising radiation
Change in DNA in genes, causing changed characteristics
Meiosis
Radiation which causes mutations by damaging DNA e.g. X rays
Mitosis
Reproduction involving fusing of male & female gametes
Mutagenic
Differences in characteristics between individuals
Mutation
Cell division which produces genetically identical daughter cells
Sexual reproduction
Something which causes mutations e.g. radiation, cigarette tar
Variation
Cell division which produces genetically different gametes
9.
Glossary – Cloning/Genetic Engineering. (Muddled – sort them out!)
Artificial Insemination
Separating embryos which then grow into genetically identical
offspring
Asexual reproduction
Injecting sperm into a female animal to fertilise her egg(s) e.g.
impregnating cows with bull sperm
Clone
1st animal ever cloned by nuclear transfer
Dolly the sheep
One parent produces genetically identical offspring
Embryo cloning
Any organism which is genetically identical to another
Fermenter
An organism with 1 or more genes added to change its
characteristics e.g. GM soya bean plants
Genetic engineering
Hormone which controls blood sugar levels, now made from
genetically modified bacteria to treat diabetes
Gene
Large container for growing bacteria on a large scale
Genetically modified
Artificial transfer of genes e.g. from human cells to bacteria
Insulin
Length of DNA which controls the production of a particular
protein. Genes produce all inherited characteristics
In Vitro fertilisation
Mother implanted with a fertilised egg/embryo which can then
develop inside her
Mitosis
Growing one or a few cells into a tissue, organ or organism
Nuclear transfer
Short loop of bacterial DNA used to transfer genes from other
organisms into bacteria, e.g. human insulin gene
Plasmid
Cell division in asexual reproduction/cloning – produces
genetically identical cells/offspring
Surrogate
IVF - removing eggs from a female & fertilising them with sperm
in a test tube
Tissue culture
Removing the nucleus from an egg cell & replacing it with a
nucleus from a donor cell
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Wellsway school science dept.
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Curriculum 2011 – AQA Science
Biology workbook
Glossary - Evolution. (Muddled – sort them out!)
Evolution
The remains of a living thing that have been preserved over time
Charles Darwin
A change in a gene
Organism
A poison that interferes with blood clotting. Used to Kill rats.
Adaptation
The concept developed by Charles Darwin that genes which
produce characteristics that are more favourable in a particular
environment will be more abundant in the next generation
Methicillin Resistant Staphylococcus aureus – a bacterium
Peppered moth
mutation
The man who proposed a mechanism for evolution
Natural selection
A characteristic that suits an organism to its environment
Fossils
A type of antibiotic
Warfarin
Anything living
MRSA
Used as classic example of how change in the environment can
cause a change in a population
Methicillin
Change in life over time
11. Additional Notes.
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Curriculum 2011 – AQA Science
12. Questions – Variation.
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Wellsway school science dept.
Curriculum 2011 – AQA Science
13. Questions – Cloning & Genetic Engineering.
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Curriculum 2011 – AQA Science
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Curriculum 2011 – AQA Science
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Wellsway school science dept.
Curriculum 2011 – AQA Science
14. Questions - Evolution.
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Wellsway school science dept.
Curriculum 2011 – AQA Science
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Wellsway school science dept.
Curriculum 2011 – AQA Science
7.
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