CB4 Natural Selection And Genetic Modification(Complete)

Question 1

Theory of evolution by natural selection was made by which two people

Answer 1

Darwin and Wallace

Question 2

What is survival of the fittest

Answer 2

Members of the same species with variation within the population and those with characteristics more suited to the environment are most likely to survive
(this was noticed by Charles Darwin on his voyages on his ship around the world)

Question 3

Darwin noticed in his journeys that characteristics can be passed on to offspring ,what is this called?

Answer 3

Inheritance/genetic inheritance

Question 4

Darwin and Wallace published their papers on evolution together and Wallace provided lots of evidence to support the the theory

Question 5

Some warning colours are used on certain butterfly species to deter predators from eating them and those with this trait are more likely to survive what is this called

Evolution
Natural selection/survival of the fittest
Genetic inheritance

Answer 5

Natural selection /survival of the fittest

Question 6

What is evolution

Answer 6

When a species changes over a long period of time

Question 7

Who published the famous book’On the origin of species’

Answer 7

Darwin did and this book gave lots of evidence to support the theory and this is why he is remembered more than Wallace

Question 8

What is the full definition for evolution by natural selection

Answer 8

That members of a species with characteristics that help them a better chance of surviving than other members of same species through variation and they will breed and that species will change over a long period of time

Question 9

Process of evolution
-Within a population there is variation
-Change in environment is introduced to population
-Natural selection occurs where individuals with characteristics that help them survive make them more likely to survive and those without the characteristic are less likely to survive
-Survivors reproduce and pass on characteristics to offspring
-Evolution occurs over time and the characteristic becomes more noticeable when the species breed over and over again over a long period of time

Question 10

Show the process of evolution of bacteria resistance to an antibiotic

Answer 10

-Some bacteria in a population are more resistant to an antibiotic then others because of variation
-Antibiotic is added to population
-Resistant bacteria survive
-Survivors reproduce and number of resistant bacteria increase
-Low levels of antibiotic remain so eventually all bacteria are resistant

Question 11

In modern biology we now know that it is important to finish the drug courses and need to constantly develop new antibiotics to fight newly evolved bacteria

Question 12

Classification shows that all living organisms have descended from a common ancestor and that we are all related in some way

Question 13

We now know that genetic diversity is important so it helps species adapt to environmental changes

Question 14

Evidence from fossils suggests humans and chimpanzees evolved from a common ancestor and we can say this through the discovery of hominids(human beings and their ancestors)

Question 15

Fossils of different hominid species have been found and they have characteristics between apes and humans and this shows how humans have evolved over time

Question 16

What is the short name for ardipithecus ramidus

Answer 16

Ardi

Question 17

Ardi is a fossil found in Ethiopia and is found 4.4 million years old and has mixed characteristics between human and apes
Structure of feet suggests she climber trees
Long arms and short legs(more like ape)
Brain the size of a chimpanzee
Structure of legs suggests she stood upright and didn’t use hands to walk

Question 18

What is the short name for Australopithecus afarensis

Answer 18

Lucy

Question 19

Lucy was a fossil found in Ethiopia and is 3.2 million years old and has mixture of ape and human like features but more human like than Ardi
-arched feet more adapted for walking than climbing
-arms and legs more similar to humans and chimpanzees
-Brain larger than Ardi but still similar to chimpanzees brain
-Lucy bones suggests she walked upright but more efficiently than Ardi

Question 20

When Leakey and his team found hominid fossils that were 1.6 million years old what was the name of the fossil and the species it belonged to

Answer 20

It was called Turkana Boy and belonged to the Homo erectus species

Question 21

Turkana boy is a mix of ape and human but more human like a than Lucy
Long arms and short legs like a human
Brain size bigger than Lucy more like a human
Legs and feet suggest he was even better adapted for walking than Lucy

Question 22

Homo Habilis(2.5-1.5 million years ago)
-Simple stone tools called pebble tools by hitting rocks together
-Scrape meat from bones or crack bones open

Question 23

Home erectus(2-0.3million years ago)
-Sculpted rocks into shape for more complex tools
-Hunt,dig,chop,scrape meat from bones

Question 24

Homo neanderthalensis(300,000-25,000 years ago)
-Evidence of flint tools and wooden spears

Question 25

Homo sapien(200,000 -now years ago)
-Flint tools widely used
-Include arrow heads ,fish hooks and needles

Question 26

What is stratigraphy(used to see how old rock is)

Answer 26

Study of rock layers,older rock layers are normally found below younger rock layers so tools or fossils with same rocks in deeper layers are older

Question 27

Looking at simpler tools can suggest the tool is ——- than a more complex tool

Answer 27

1older
Simpler tools used longer ago as more complex tools are made later on when the brain size of the species increases

Question 28

What is carbon -14 dating

Answer 28

This is when stone tools usually are found with carbon containing material and this is used to date the material

Question 29

What is a pendactyl limb

Answer 29

A limb with 5 digits

Question 30

Species that have pendactyl limbs mean we can say that they have evolved from a common ancestor despite the limb not doing the same job

Question 31

Classification is used to put living organisms into groups , what are the 5 kingdoms called

Answer 31

Animals
Plants
Fungi
Prokaryotes(single cell organisms with no nucleus)
Protists(Eukaryotic single cell organisms)

Question 32

5 kingdoms are still used today but are a bit out of date, technology has increased and we can now see things like sequence of dna and genes
Now we use a 3 domain system and what are they called

Answer 32

3 domains
Archae-look similar to bacteria but are quite different,
Bacteria-true bacteria
Eukarya-broad range of organisms like fungi plants animals and protists

Question 33

Which scientist made the 3 domains

Answer 33

Carl Woese

Question 34

Using RNA sequencing Woese found that members of the prokaryote kingdom were not as closely related as first thought using the increase in technology

Question 35

Selective breeding is when humans artificially breed plants or animals so a certain genes for a characteristic remains or increases in the population
What are some examples of this being used

Answer 35

Animals that produce more mart or milk
Plants with bigger fruits
Crops with disease resistance

Question 36

Process of selective breeding;
-From existing stock select ones that have desirable characteristic and breed them
-Select offspring that best show this characteristic and breed them
-Continue process over generations and the desirable characteristic gets stronger and stronger

Question 37

A farmer has a herd of sheep with different amounts of wool on them ,describe how he can use selective breeding to increase the amount of wool on sheeps

Answer 37

-Choose current sheep with most wool and breed them
-Choose best offspring and breed them
-Continue over several generations and the desirable characteristic will get stronger

Question 38

Selective breeding has advantages ;
-Means farmers looking to increase yield can do so through selective breeding (eg.increase milk yield produced by cows)
-It can be also used in medical research for testing

Question 39

Selective breeding also has disadvantages;
Reduces the gene pool(alleles in a population)
Inbreeding can cause health problems because smaller gene pool means larger chance of inheriting genetic defects
There can be problems if a new disease appears as if there is no variation then it is more likely the population won’t have resistance to the disease and may risk them all dying

Question 40

Tissue culture involves growing cells on an artificial growth medium
The process is easy and useful and many clones can be made with all the same characteristics

Question 41

-Choose plant you want to clone based on its characteristics (tasty fruit)
-Remove several small pieces of tissue from parent plant(best results from fast growing roots or shoot tips)
-Grow tissue in growth medium with nutrients and growth hormones in sterile conditions
-As the plant produces roots or shoots they can be moved to potting compost to keep moving

Question 42

Tissue culture can also be used in medical research on animals(you can’t test it on a whole animal but only on one organ of the animal)

Question 43

This means you can look at the effects of a substance or environmental change without affecting the whole organism

Question 44

-Extract a sample of the tissue
-The cells in the sample are separated using enzymes
-The cells are placed in a culture vessel and bathed in growth medium with all nutrients they need to grow
After it has grown the cells can be delegated again and grow more
-Once the tissue culture has grown it can be stored for further use

Question 45

Genetic engineering (eg.insert insulin DNA into plasmid DNA-plasmid is the vector here)
-The DNA for the insulin is cut with restriction enzymes and so is the plasmid with the SAME RESTRICTION ENZYME
-They are then left with STICKY ENDS
and are mixed with LIGASE ENZYME
-They are then joined by the ligase to make recombinant DNA
-The recombinant DNA is inserted back into the cell

Question 46

What is a vector and give 2 examples

Answer 46

Something that is used to transfer dna into a cell(plasmid and virus)

Question 47

What is genetic engineering

Answer 47

Involves modifying and organisms genome to introduce desireable characteristics using other pieces of DNA from other cells and inserting it into the DNA of the other organisms cell to introduce desire able characteristic

Question 48

Genetic engineering
-Used in agriculture to make crops resistant to diseases
-Question whether safe for animals and plants
-May affect the humans in a bad way
- The newly modified gene can get out into the environment through cross breeding(if an animal was inserted with a gene that made it not get a disease and then the disease somehow got they gene for the resistance then it may evolve and produce resistance so the cows cannot avoid the disease )

Question 49

Bacilus thuringiensis is a bacterium that produces a toxin that kills insects that are harmful to crops
If crops are genetically modified with this bacterium then they will be resistant to the pests
However if the insects are constantly exposed to the bacterium they may develop resistance to it and a new solution will need to be made

Question 50

Due to increase in world population we need to keep up with food demands and gm crops can be made to increase crop yield(grow better in droughts)
Why do some think it is not a good idea

Answer 50

Some people think others lack food because of poverty and not crop failure
Countries may become too dependant on companies who sell gm seeds
Sometimes poor soil is the main reason for failure and not even gm plants can survive

Question 51

Fertilisers can be used to put minerals in soil that plants need for growth ,why might it be dangerous for the outer environment

Answer 51

Excess fertiliser can cause problems in rivers and lakes through eutrophication

Question 52

Pests can be controlled without gm organism’s and through biological controls(predators and parasites to eat the problem)
But the biological controls may also become a problem too in later life

Question 53

Exam Question
A)Which of these stone tools were made by humans most recently(1)
Handaxe
Arrowhead
Cutting stone
Hammer stone
B)Suggest how these tools may have helped early humans to survive(2)

Answer 53

A)Arrow head
B)hunting/fighting/defence
Skinning animals
Chopping wood
Making clothes

Question 54

Exam question
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 54

Need 2 of these points
Better adapted members survive/best suited
Competition occurs
These members will reproduce
Members who cope less well die
Refer to natural selection

Question 55

Exam question
Explain why the fossil record may be incomplete (2)

Answer 55

Some fossils are yet to be found
Fossils may be damaged
Conditions may not be right for the fossils to form

Question 56

Exam question
Homo habilis and homo erectus lived at the same time but homo erectus was more modern
Suggest a reason for the extinction of Homo habilis (2)

Answer 56

Outcompeted by homo erectus
By things like resources

Question 57

Exam question
Explain how scientists can use plant breeding programs to produce plants with bigger fruits(3)

Answer 57

Select current plants with largest fruits and breed them
Choose offspring with the best fruits
Breed over generations to produce bigger and bigger fruits

Question 58

Exam Question
A plant can be used in the production of biofuels
Discuss the advantages and disadvantages of the use of biofuels
(4)

Answer 58

Advantages;
Removes CO2 when growing
Less use of fossil fuels
Renewable source
Disadvantages
Takes up land
Reduces biodiversity
Depends on weather

Question 59

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

Answer 59

Advantage;
Crops produce toxin that kills inscect
Increases yield/less crops damaged
Disadvantage;
Cross fertilisation /pollination with other weeds
Weeds may then develop resistance to toxin
OR
GM crops cost more
Farmers cannot afford them

Question 60

Describe the risks associated with cloning mammals(3)

Answer 60

Reduces gene pool
Genetic defects
Susceptible to same diseases

Question 61

Ardi—Lucy—Homohabilis—homoerectus—homoneanderthalensis-homosapiens-