Paper 1 - Natural Selection & Genetic Modification

Question 1

Who developed the theory of evolution

Answer 1

Charles Darwin

Question 2

What is Darwins theory of evolution

Answer 2

Darwin’s theory of evolution describes how organisms may change over time through natural selection. This explains how changes in the environment can lead to changes in characteristics of species as on the best adapted individuals survive and breed, passion non their characteristics to their offspring in their genes

Question 3

What does natural selection mean?

Answer 3

The best adapted organisms in a population are most likely to survive and reproduce

Question 4

Which term is also used to describe natural selection

Answer 4

survival of the fittest

Question 5

According to Darwins theory of evolution, how do new species evolve?

Answer 5

Natural selection; this involves survival of the fittest

Question 6

Define the term evolution

Answer 6

Changes in the heritable characteristics of organisms over generations/time; [1 mark]

Question 7

What are fossils?

Answer 7

They are imprints or remains of organisms which were alive millions of years ago

Question 8

Explain why there are gaps in the fossil record

Answer 8

Not all fossils have been found yet
Not all parts of organisms become fossils
Some fossils have been destroyed in the rock cycle

Question 9

what observations did Darwin make on the Galapagos islands that helped him develop his theory of evolution?

Answer 9

he observed finches on the Galapagos Islands
they were similar in size
but had small changes in their beaks
these suited the specific food on individual islands

Question 10

Why was Darwin reluctant to publish his findings when he returned form his voyage to the Galapagos islands?

Answer 10

His idea challenged God/Church
The Church was very powerful at the time

Question 11

Describe how giraffes have evolved long necks (6 marks)

Answer 11

in every population, there is variation
some giraffes had slightly longer necks
some individuals have characteristics that give them an advantage
the giraffes with longer necks could reach more leaves for food
these organisms are more likely to survive and reproduce: survival of the fittest
their offspring are more likely to inherit these adaptations through inheritance
this process has been repeated over many generations
now all giraffes have longer necks

Question 12

Name some sources that provide evidence for evolution

Answer 12

Fossils / example of a fossil e.g Ardi or Lucy

Similar bone structures across different species

Continuous variation / example of continuous variation e.g. Darwin’s finches

Discovery of different tools that show the evolution of humans over time

Antibiotic resistance in bacteria

Question 13

Where in rocks do we usually find the oldest fossils

Answer 13

Bottom of rocks

Question 14

What are the names of the two fossils found that provide evidence for human evolution? Describe them

Answer 14

Ardi - female human-like fossilised skeleton that dates from 4.4millions years ago. Shows she was probably able to walk upright but she had very long arms and long big toes. The bones that make up Ardi’s feet suggest that humans and chimpanzees evolved separately.

Lucy - female human-like fossilised skeletons that dates from 3.2 million years ago. Lucy’s bones suggest that she walked in an upright position like a human, but possessed a relatively small ape like skull. Lucys foot bones show that she had similar feet to modern humans but with much more curved toes.

Question 15

What is MRSA

Answer 15

Antibiotic resistant bacteria

Question 16

Why can bacteria evolve more quickly than other species?

Answer 16

They can evolve more quickly because they reproduce quickly

Question 17

What was the name of the first antibiotic discovered?

Answer 17

Pencicillin

Question 18

what time of illness will antibiotics treat?

Answer 18

Bacteria

Question 19

Explain why antibiotics are not useful against viral pathogens

Answer 19

Antibiotics can only disrupt cell functions e.g. respiration

Viruses do not carry out cell functions

Question 20

What strategies can be used to decrease the rate at which antibiotic resistance evolves

Answer 20

Reduce the use of antibiotics eg only prescribing antibiotics when necessary

Ensuring correct use of antibiotics e.g. completing a whole prescribed course

Seeking alternative treatments to current antibiotics e.g. developing other types of antibacterial medication / new types of antibiotics;

Question 21

Doctors are now prescribing fewer antibiotics to reduce the evolution of antibiotic resistant bacteria. Describe the process of evolution of antibiotic bacteria. [5 marks]

Answer 21

in every population there is variation,

some mutations protect the bacterial cell from the effects of the antibiotic

Bacteria without the mutation die or cannot reproduce when the antibiotic is present

so those that have the gene for resistance have an advantage and are more likely to survive and can reproduce

this is survival of the fittest

because of inheritance, the offspring of those with the advantageous characteristic are more likely to have it

this process is repeated over many generations
until a new species is produced

Question 22

How is natural selection different from selective breeding?

Answer 22

natural selection occurs when the best adapted organisms in a population are most likely to survive and reproduce
the offspring of these organisms are likely these adaptations
this will lead to evolution
all organisms are evolving

selective breeding is artificial selection
- this occurs when people specifically choose organisms to reproduce because of desirable characteristics
- the offspring of these organisms are likely to have these characteristics
eg cows, dogs and crop plants have been selectively bred

Question 23

State two visible differences between Eohippus and modern horses

Answer 23

Eohippus is much smaller than the modern horse

Eohippus has a much shorter / less hairy tail than modern horses

Eohippus has shorter mane than the modern horse

Eohippus has faint stripes across its back while the modern horse lacks stripes across the body

Eohippus has proportionally smaller hooves/feet in comparison with modern horses

Question 24

In the 18th century Carl Linnaeus developed a classification for organisms - what was this based on

Answer 24

characteristics

Question 25

The largest group in the Linnaeus system are what?

Answer 25

The kingdoms

Question 26

The smallest group in the Linnaeus system are?

Answer 26

The species

Question 27

Linnaean system of classification - name the five kingdoms

Answer 27

Animals (all multicellular organisms that digest food inside their bodies)

Plants (multi-celled organisms that are able to photosynthesise - all green plants)

Fungi (usually multi celled organisms that digest food outside their bodies - moulds, mushrooms, yeast)

Protists (usually single cells with nucleus and other sub cellular structures) - amoeba, chlorella, and plasmodium)

Prokaryotes (single celled with genetics material free in cytoplasm eg bacteria, blue-green algae)

Question 28

Who developed a new classification for organisms and what was it based on? What does it group organisms into?

Answer 28

in the 20th century Carl Woese developed a new classification for organisms based on genetics.

It groups organisms into domains

Question 29

What are the groups in the three-domain classification

Answer 29

Bacteria, Archae, Eukaryota

Question 30

Give examples in each of the three domain classifications

Answer 30