Evolution

Question 1

What is variation?

Answer 1

Differences between organisms

Question 2

What affects variation?

Answer 2

genetics, environment or both

Question 3

How common and dangerous are mutations?

Answer 3

Fairly common, random and usually have no effect

Question 4

What can mutations cause?

Answer 4

Differences in populations of species

Question 5

What can mutations alter in rare cases? Is this advantageous?

Answer 5

The phenotype- usually a disadvantage but can give a selective advantage

Question 6

What is artificial selection?

Answer 6

Selectively breeding animals or plants together that share desired characteristics

Question 7

What has selective breeding led to?

Answer 7

• disease resistant crops
• aniamls which produce more meat or milk
• domestic dogs with a gentl nature
• large, nice smelling and unusual flowers

Question 8

What is inbreeding?

Answer 8

Breeding two animals together which have very similar genes

Question 9

What is the danger of inbreeding? Why?

Answer 9

Can lead to lots of genetic diseases as there is a smaller gene pool, leading to a higher frequency of disease alleles

Question 10

What can be studied to help scientists understand what controls different characteristics?

Answer 10

Twins

Question 11

What are two useful characteristics of wheat?

Answer 11

• disease resistance

- many grains

Question 12

How can a breeder for example breed a very fast dog?

Answer 12

• select dogs that can run fast
• breed them together
• continue to repeat the process over many generations

Question 13

What is natural selection?

Answer 13

The theory that over the last 3.8 billion years, small changes in phenotypes, caused by mutations, led to changes in populations

Question 14

What is evolution?

Answer 14

The belief that if changes are sufficiently different in two populations may no longer to able to breed and therefore have become two new species

Question 15

Why did Darwin and Wallace believe some populations have a selective advantage?

Answer 15

If a population has variation, then a change in the environment will lead to some individuals having particular alleles that provide a selective advantage in response to that change

Question 16

Why to advantageous alleles become more prevalent in species over time?

Answer 16

Those organisms who possess those alleles are better adapted to survive and reproduce so the frequency of the alleles in the population increases. They survive and pass on the characteristic to their offspring

Question 17

What is a mutation?

Answer 17

a change in the DNA code

Question 18

What was Lamarck’s evolution theory?

Answer 18

Organisms survived by adapting to their enivironment and to do so, body parts would develop during an organism’s life. These were then passed onto the next generation. Organisms develop into another and don’t become extinct.

Question 19

Why was Lamarck’s theory largely discredited?

Answer 19

He could not provide a plausible mechanism for how his theory could work. The lack of evidence made such sudden evolutionary changes seem even more impossible

Question 20

What provides evidence for natural selection?

Answer 20

• fossil record
• antibiotic resistant bacteria
• gene/inheritance understanding

Question 21

In what three ways can fossils be formed?

Answer 21

• bones preserved from decay due to environment (glaciers, peat bogs)
• buried bodies with bones replaced by minerals as body decays
• traces (footprints) or root traces left behind

Question 22

What do fossil records show linked to natural selection?

Answer 22

Many species have become extinct and that over time, species show a greater diversity

Question 23

What allows fossils to be arranged chronologically?

Answer 23

Carbon dating

Question 24

Why are there gaps in the fossil record?

Answer 24

Some organisms only had soft tissue so left little evidence behind.
Some fossils may have been destroyed through geological activity.

Question 25

Why is evolution/natural selection easy to observe in bacteria?

Answer 25

• bacteria mutate quicker and reproduce fast so we are able to track adaptations and changes to them easier

Question 26

What is a classic example of anantibiotic resistant hospital superbug?

Answer 26

MRSa

Question 27

how is superbug development aided?

Answer 27

• overuse of antibiotics

- people not finishing a course of antibiotics

Question 28

What is an extinction?

Answer 28

When there are no remaining organisms of a species left alive

Question 29

What is the principle explanation for extinctions?

Answer 29

A change to the environment occurs where the species is not able to adapt quickly enough to it through natural selection

Question 30

What are examples of causes of extinction?

Answer 30

• changes to the environment over time
• new predators
• new diseases
• new more successful competitors
• a single catastrophe like a volcano eruption

Question 31

Why are asexually reproduced organisms at a higher risk to a change in the environment?

Answer 31

• they are clones of one enough (identical DNA)
• so they have no variation
• which means they can’t respond to a change in the environment