Topic 4 - Evolotion, Natural Selection, Genetic Engineering & Genetic Modification

Question 1

Fossil remains of Ardipithecus ramidus were discovered in Ethiopia.
Describe the evidence that scientists might have used to show that Ardipithecus ramidus inhabited the earth earlier than Homo habilis. (2)

Answer 1

Differences in the structural features of the fossils (1)
Ardipithecus ramidus is deeper in the rock layer than homo habilis (1)

Question 2

Suggest an explanation for the extinction of Homo habilis. (2)

Answer 2

Likely to be out competed by homo erectus (1)
For resources essential for survival (1)

Question 3

Below are 2 stone tools, one used by Homo habilis and one used by Homo erectus. (2)
A - blunt and more circular
B - sharper and pointier
Explain which stone tool was most likely used by Homo Erectus (2)

Answer 3

Stone B, as it is more sophisticated (1)
And Homo erectus lived more recently than Homo habilis (1)

Question 4

The population of humans on earth has increased significantly leading to food shortages. The growth of drought-resistant crop plants could lead to an increase in food supply.
Describe how drought-resistant crop plants can be produced. (3)

Answer 4

Genetic variation means that some plants will be tolerant of drought conditions and these can be selected (1)
Cross pollinate these plants and grow the seeds under drought conditions (1)
Select offspring and repeat over many generations (1)

Question 5

A scientist said that each red blood cell found contained a nucleus. In humans, each mature red blood doesn’t have a nucleus. Suggest why not having a nucleus in a red blood cell is an advantage. (2)

Answer 5

More haemoglobin can be carried (1)
Increase in surface area to volume ratio/biconcave shape (1)
Can carry/absorb more oxygen (1)
Red blood cells are only carriers/don’t need to carry out processes like protein synthesis (1)

Question 6

Explain why fossils of dinosaurs are often incomplete. (3)

Answer 6

Soft body tissues decay/decompose (1)
Some parts/bones may have been eaten/moved away from the skeleton by animals before fossilisation (1)
Some parts are not found/eroded/corroded by pressure/heat when in the ground (1)

Question 7

Penicillin inhibits the synthesis of the cell wall in bacteria.
Explain the effect of penicillin on bacterial & human cells. (3)

Answer 7

Penicillin prevents the cell from dividing, as the cell cannot make a new cell wall. (1)
Because human cells don’t have a cell wall (1)
They are unaffected by penicillin (1)

Question 8

Penicillin, isolated from the fungus, was the first antibiotic used to treat bacterial infections and is still widely used today. Scientists have genetically modified bacteria to produce large amounts of penicillin. Describe how scientists would produce a genetically modified bacterium that produces penicillin. (4)

Answer 8

Use restriction enzymes to remove the gene and cut the plasmid (1)
Use ligaments to join the DNA molecules together (1)
Cut the gene from 5he genome of the fungus and extract a plasmid from the bacteria (1)
Insert the recombinant plasmid back into the bacteria. (1)

Question 9

MRSA is a bacterium that has evolved to become resistant to antibiotics. With reference to Darwin’s theory of evolution by natural selection, explain how MRSA bacteria have evolved to become resistant to antibiotics. (6)

Answer 9

• bacteria reproduce rapidly generating a large population
• there is variation among a bacterial population
• some bacteria develop a resistance to antibiotics through mutation
• antibiotic treatment exerts a selection pressure
• bacteria resistant to antibiotics survive •antibiotic resistance inherited
• non-resistant bacteria do not survive
• levels of antibiotic resistance in a population of bacteria increase

Question 10

Variation may arise due to the geographic isolation of species. Explain how geographic isolation of members of 1 species can lead to a new species evolving. (3)

Answer 10

Speciation (1)
Different geographical areas may have different selection pressures/environmental conditions (1)
Those individuals suited/adapted to this environment will survive and breed (1)
Adaptations/genes passed down to the offspring (1)
New species unable to breed with original (1)

Question 11

The Stone Age tool made most recently is the (1)

A handaxe
B arrow head
C cutting stone
D hammer stone

Suggest how these tools may have helped early humans to survive. (2)

Answer 11

arrow head (1)

Hunting/fighting/defence (1)
Preparing/cooking food (1)
Making clothes (1)
Construction of shelters/new tools/to sharpen tools (1)
Making fire (1)

Question 12

Mitochondrial DNA can be used as evidence for human evolution.
Explain why mitochondrial DNA is used rather than nuclear DNA. (2)

Answer 12

Higher abundance (1)
More stable over time/less susceptible to decay (1)
High mutation rate (1)
Inheritance down female line (1)

Question 13

Describe how fossil evidence can be used to show that humans have evolved. (2)

Answer 13

Show changes in body structure (1)
Changes in stone tools (1)

Question 14

Below are the limbs of six organisms. (Human, lizard, cat, whale, bat & frog)
Many scientists believe that these 6 organisms evolved from one common ancestor.
Describe the evidence that supports this belief. (3)

Answer 14

All have digits/fingers (1)
All have similar bones/ulna/radius/carpals (1)
All have a humerus bone (1)
Pentadactyl limb (1)

Question 15

Fossils can provide evidence for evolution.
Explain why the fossil record is incomplete. (2)

Answer 15

Soft tissue of organisms doesn’t form fossils (1)
Some fossils are yet to be found (1)
Fossils may be damaged (1)
Conditions not correct for fossil formation (1)
Fossils may only be fragments/not whole organisms (1)

Question 16

Suggest how photosynthesis could have changed the gas content of the atmosphere. (2)

Answer 16

Lowered the levels of carbon dioxide/carbon dioxide absorbed (1)
Increased the level of oxygen/oxygen absorbed/taken in (1)

Question 17

Suggest why such a high % of oxygen in the atmosphere was needed for large land animals to evolve. (2)

Answer 17

Large animals are more complex/have more cells/carry out greater number of functions (1)
For more aerobic respiration (1)
For more energy (1)

Question 18

Suggest how the size and shape of their beaks enabled all of the different types of finches to survive. (2)

Answer 18

Different sized beaks allowed finches to feed on different food types (1)
Less competition between species (1)

Question 19

Darwin’s finches are an example of speciation due to (1)

A selective breeding
B geographic isolation
C hybridisation
D the development of ring species

Suggest how these species of finches could have evolved. (3)

Answer 19

geographic isolation (1)

Variation between species/beak sizes/shapes (1) Due to mutation (1)
Competition for resources (1)
Survival of the fittest/those best adapted to their environment survive (1)
Those who survive pass their genes/character onto their offspring (1)
Natural selection (1)

Question 20

Pompeii worms are found in hydrothermal vents in the Pacific Ocean.
The temperature of these hydrothermal vents can be very high.
Suggest a feature that helps to protect the Pompeii worm from the extreme heat. (1)

Answer 20

Large surface area to eliminate heat loss (1)
Insulating fat layer (1)

Question 21

Pompeii worms were discovered by French marine biologists in the early 1980s.
Explain how these biologists may have validated the evidence for the discovery of the Pompeii worms. (2)

Answer 21

publishing the evidence and results in scientific journals (1)
getting other scientists to review their experiment/repeat the experiment (1)
scientists to investigate hydrothermal vents (1)
participating in scientific conferences to discuss experiment/results (1)
taking samples of organisms in hydrothermal vents for comparison (1)

Question 22

Variation in a population enables evolution to occur.
Explain, using Darwin’s theory of evolution, how variation can lead to a species evolving. (2)

Answer 22

competition (occurs between members of a species) (1)
best suited / better adapted members out-compete and survive (1)
these members will reproduce (more times) (1)
the members who cope less well will die/extinction occurs (1)
reference to natural selection (1)

Question 23

Evolution can lead to speciation.
Describe what is meant by the term speciation. (2)

Answer 23

The formation of a new species/characteristic (1)
Due to geographical isolation (1)
No longer able to breed with original species (1)

Question 24

The range in heights of students in a class is due to
A environmental influences only
B genetic influences only
C environmental and genetic influences
D neither environmental nor genetic influences

Answer 24

environmental and genetic influences

Question 25

Taller animals may have an evolutionary advantage.
Explain how evolution by natural selection brings about changes in a species. (3)

Answer 25

most individuals within a population vary slightly from one another (1)
most organisms produce more young than will survive to adulthood / overproduction (1)
there is much competition within and between species (1)
those organisms with advantageous characteristics will survive (1)
the advantageous characteristics will be inherited/better adapted organisms are more likely to survive to reproduce (1)

Question 26

Genetic engineering can be used to produce plants that are resistant to herbicide.
One herbicide works by preventing the activity of an enzyme.
Some bacteria have a form of this enzyme that is not affected by the herbicide.
Suggest how genetic engineering can be used to produce plants resistant to this herbicide. (3)

Answer 26

Use of enzymes (1)
Isolate/remove/cut out gene/DNA (1)
Coding for enzyme (1)
From bacteria (1)
Insert gene/DNA into crops/plants (1)

Question 27

A herbicide is sprayed onto the leaves of plants.
Suggest which vessel could transport the herbicide from the leaf to other parts of the plant. (1)

Answer 27

In the phloem

Question 28

Name two structures other than DNA, that bacterial cells have but animal cells do not. (2)

Answer 28

Cell wall (1)
Capsule/slime coat (1)
Small ribosome (1)
Pilli (1)
Mesosome (1)

Question 29

Describe how the plasmid can be used to genetically modify a bacterial cell to contain a human gene. (3)

Answer 29

Removal of (human) gene (1)
Plasmid is cut/removed from bacteria (1)
Using enzyme (1)
Gene/DNA (from human cell) added to plasmid (1)
Plasmid inserted into bacterium (1)

Question 30

Suggest how a named product from genetically modified (GM) bacteria can benefit humans. (2)

Answer 30

To produce hormones/insulin/vaccine/medicines (1)
For diabetes/can be used by vegans/prospduces large quantities (1)

Question 31

In 2011, South Korean scientists genetically engineered a cell from a beagle.
They then cloned this cell to create a beagle.
They called this beagle Tegon.
Tegon glows in the dark when UV light is shone on him.
To genetically engineer the original cell so that it would glow, the scientists had to obtain a suitable gene.
Describe the stages that a scientist would complete to obtain this gene (2)

Answer 31

Select a species that glows when UV light is shown on it (1)
Identify the gene location (1)
Cut the gene out (1)
Using a restriction enzyme (1)

Question 32

In 2011, South Korean scientists genetically engineered a cell from a beagle.
They then cloned this cell to create a beagle.
They called this beagle Tegon.
Tegon glows in the dark when UV light is shone on him.
Describe the stages used in the laboratory to clone and produce Tegon from the genetically engineered cell. (6)

Answer 32

• diploid nucleus is removed from the genetically engineered cell
• making a lone nucleus
• a donor egg is enucleated/its nucleus is removed
• the diploid nucleus from the GE cell is inserted into the enucleated egg cell
• division of the nucleus is stimulated
• by electric shock/chemicals
• cell divides by mitosis
• cells put into surrogate mother
• cells divide further and differentiates to form an embryo
• Tegon born and is a glow in the dark beagle

Question 33

Suggest the advantages of cloning mammals, such as dogs, for use in medical research into human diseases. (3)

Answer 33

the clones will all be genetically identical (1)
so test results will be similar/not affect by genes (1)
the clones could be GE to have specific human diseases /(dogs have) similar diseases/disorders to humans (1)
dogs and humans are mammals/have similar anatomy / physiology / DNA (1)

Question 34

Purple tomatoes are transgenic plants that have been produced by genetic
engineering.
As a result of genetic modification, these tomatoes produce a new substance which has health benefits and turns the tomatoes purple.
Name this substance. (1)

Answer 34

Flavonoids/bioflavanoids

Question 35

What is inserted into the DNA of another plant to make it transgenic? (1)

A a gene from another species
B a gene from the same species
C chromosomes from the same species
D proteins from another species

Answer 35

a gene from another species

Question 36

Describe how Agrobacterium tumefaciens can be used to create transgenic plants. (6)

Answer 36

genetic modification:
• transferring a gene from one organism to another
• restriction enzymes to cut the gene out
• plasmids used to carry gene
• sticky ends to join complementary bases
• ligase to join the DNA

use of Agrobacterium:
• Agrobacterium is a vector (for the gene)
• the Agrobacterium has a suitable gene added to it
• example of a suitable gene eg drought resistance / insect resistance / larger yield / for flavonoids
• Agrobacterium naturally invades plant cells
• its DNA is incorporated into the plant’s DNA
production of plants
• plant sprayed with Agrobacterium
• crown gall (formed)
• crown gall is cut into small pieces
• leaf discs are incubated with Agrobacterium
• (crown gall tissue / leaf discs) grown in tissue
culture:
• explants
• grown into crops

Question 37

Bacillus thuringiensis contains a gene that codes for a toxin.
Explain one advantage and one disadvantage of introducing this gene into crop plants. (4)

Question 38

In May 2011, the Food Standards Agency stated that meat and milk produced from cloned animals should be allowed to go on sale to the public.
Describe the risks associated with cloning mammals. (3)

Answer 38

(cloned animals) tend to be larger at birth/body organs /named organ enlarged (1)
embryo rejected/fails to develop normally/many cloned mammals failed to develop (1)
(cloned animals) early death /speeds up aging (1)
narrowing of the gene pool / less (genetic) variation (1) genetic disorders / defects (1) susceptible to same diseases / pathogen (1)

Question 39

A cloned animal contains genetic information that is identical to its parent.
Describe the stages in the production of a cloned mammal. (6)

Answer 39

• use of body cell
• nucleus removed from body / parent cell
• use of egg cell
• nucleus removed from egg cell/enucleated egg
• nucleus (from body cell) transferred to enucleated egg
• electric shock;
• to stimulate cell division
• mitosis
• formation of embryo;
• embryo implanted
• into surrogate

Question 40

Fertilisation takes place during sexual reproduction to produce genetically different offspring.
Fertilisation occurs when (1)

A diploid gametes combine to produce a diploid zygote
B diploid gametes combine to produce a haploid zygote
C haploid gametes combine to produce a diploid zygote
D haploid gametes combine to produce a haploid zygote

Answer 40

haploid gametes combine to produce a diploid zygote

Question 41

Genetically different organisms contain different DNA codes that produce different proteins.
Describe the process that takes place in the nucleus during the first stage of
protein synthesis. (2)

Answer 41

Transcription (1)
DNA unzips (1)
Formation of mRNA (1)
Complementary to DNA (1)

Question 42

Describe how scientists can use plant breeding programmes to produce maize plants with larger cobs. (3)

Answer 42

Selection of individuals with favourable characteristics/largest cobs (1)
Cross breeding of selected individuals (1)
Selection of offspring (1)
Repeat process over time (1)

Question 43

There has been an increase in the use of pesticides during the last 1000 years.
Explain how the use of pesticides may benefit maize production. (2)

Answer 43

Reduce number of pests (1)
Reduced damage to crops (1)
Increased yield (1)
OR
Kills weeds (1)
Reduces competition for resources/light/space (1)
Increased yield (1)

Question 44

Maize plants can be used in the production of biofuel.
Discuss the advantages and disadvantages of the use of biofuel. (4)

Answer 44

Advantages:
Removes CO2 when growing (1)
Less use of fossil fuels (1)
Reduced SO2 emissions
Renewable/can be grown quickly/sustainable (1)

Disadvantages:
Reduced food production (1)
Takes up land (1)
Reduced biodiversity (1)
Crop growth is weather dependant (1)

Question 45

Plants grown for biofuel could be genetically modified.
The microorganism used as a vector to produce transgenic plants is (1)
A Agrobacterium tumefaciens
B Bacillus thuringiensis
C Fusarium venenatum
D Saccharomyces cerevisiae

Answer 45

Agrobacterium tumefaciens