Topic 4 Using Spec

Question 1

What did Charles Darwin believe

Answer 1

His theory of natural selection proposed that all species have evolved from simple life forms that first appeared on earth more than 3 billion years ago

Question 2

What is genetic variation

Answer 2

Different individual animals in a population have different combinations of genes which show genetic variation

Question 3

How does genetic variation link to survival of the fittest

Answer 3

Individuals that are best adapted to the environment due to their genes will have a greater chance of survival

Question 4

How does survival of the fittest link to successful breeding

Answer 4

The individuals with the best chance of survival are most likely to successfully breed and pass these beneficial adaptations to the offspring

Question 5

What were some problems with Darwin’s theory

Answer 5

Some scientists regarded the evidence as inconclusive
Challenged common belief that god created the natural world
At time genes weren’t discovered so Darwin was unable to suggest a method for the passing of characteristics between generations

Question 6

What year did Wallace and Darwin produce writings

Answer 6

1858

Question 7

What does antibiotic resistance in bacteria do and for evolution

Answer 7

Is a source of evidence for evolution
Causes bacteria to reproduce rapidly
If a mutated bacterium is resistant to antibiotics, it will survive exposure to antibiotics and go on to reproduce.

Question 8

What is an example of an antibiotic resistance bacteria

Answer 8

MRSA

Question 9

How does the pentadactyl limbs provide scientist with evidence for evolution

Answer 9

Helps compare similar structures in similar animals to prove that these organisms have evolved from the same organism
5 fingers
Many vertebrates

Question 10

What kind of animals have pentadactyl limbs

Answer 10

Animals with backbones ( vertebrates)

Question 11

How can fossils be used as evidence for human evolution

Answer 11

Fossils can be dated so scientists have evidence for what organisms looked like at different periods of time. Comparing fossils indicates how humans have changed over time

Question 12

What is an ardi

Answer 12

Oldest fossilised human that remains are of ardi
From the species ardipithecus ramidus
4.4 million years ago

Question 13

What was the Lucy fossil

Answer 13

From the species Australopithecus afarensis
3.2 million years old
Her bones suggested that she walked in an upright position like a human
Feet bones suggest she had feet similar to modern humans

Question 14

Who is Leakey

Answer 14

archaeologist (fossil-hunter)
more recent discoveries of human fossils
1.6 million years ago

Question 15

How have stone tools developed

Answer 15

Very basic tools found dating back to 2.6 mill years ago - mainly flakes of rock with a sharp edge
Around 1.6 mill years ago tools became more sophisticated and abundant

Question 16

How can we tell when the stone tool was in use

Answer 16

Determine how deeply the artefact was buried. The deeper the object was stored, the older the object.
Compare the design to other stone tools that are already dated.

Question 17

What does carbon dating do

Answer 17

Tells us when the rock was originally formed

Question 18

What is the 3 domain system and who created it

Answer 18

Carl Woese proposed the 3 domain system. This classifies organisms based on chemical analysis.

Question 19

What are the 3 domains

Answer 19

Archaea
Bacteria
Eukaryota

Question 20

What is archaea

Answer 20

Primitive bacteria, many of which are extremophiles

Question 21

What is eukaryota

Answer 21

Organisms that possess complex sub cellular structures

Question 22

Why is selective breeding done on food crops

Answer 22

Causes disease resistance in food crops which is a useful characteristics as it improves yield

Question 23

Why are animals used in selective breeding

Answer 23

animals that produce more milk or meat are also useful for yield-related reasons.

Question 24

What is the process of tissue culture

Answer 24

Tissue sample taken from a plant
Then the cells are sterilised
Sample treated with hormones to trigger cell division and grown on an agar plate
ball of cells called a callus, forms and more hormones are added to cause roots and stems to grow.
plants can now be planted into soil.

Question 25

Advantages of tissue culture in medical research

Answer 25

can use cell cultures to study cell processes and drug effectiveness
can also use them to study viruses that cannot survive outside of cells.

Question 26

Advantages of tissue culture in plant breeding programs

Answer 26

can produce lots of genetically identical plants quickly from tissue culture cells.
can produce these plants any time of year in a lab
can increase the population numbers of rare plant species.

Question 27

What is genetic engineering

Answer 27

Modifying an organisms genome by introducing a gene from another organism to produce a desired characteristic

Question 28

How is vitamin A rice an example of genetic engineering

Answer 28

Lack of vitamin A can lead to blindness
Communities that lacked vitamin A used rice as the core of their diet
Therefore a gene that produced vitamin A was taken from bacteria and added to rice producing golden rice ( rich in vitamin A)

Question 29

How is insulin producing gene an example of genetic engineering

Answer 29

gene that produces insulin can be inserted into bacteria. Those bacteria can then mass-produce insulin to treat people with diabetes.

Question 30

Describe the stages of genetic engineering

Answer 30

Restriction enzymes (RE) cut a desired gene out of a chromosome 
RE cut a vector so now target gene and vector have exposed sections of single stranded dna known as sticky ends 
Enzyme called ligase used to join up sticky ends of gene and vector so now vector carries target gene. Marker gene added into vector to make it east to check that vector has taken up the target gene 
If the gene is delivered into cells by the vector before they have differentiated (at the egg or embryo stage), all cells in the developed organism will have the gene and show the characteristic.