The development of understanding of genetics and evolution

Question 1

What is a species?

Answer 1

a group of similar organisms that can reproduce to give fertile offspring

Question 2

What is speciation?

Answer 2

the development of a new species - this occurs when populations of the same species become so different that they can no longer successfully interbreed to produce fertile offspring

Question 3

What is the evidence for evolution?

Answer 3

fossils and the development of antibiotic resistance in bacteria

Question 4

What are fossils?

Answer 4

are the remains of organisms from millions of years ago, which are found in rocks

Question 5

What can fossils be formed from?

Answer 5

• from parts of organisms that have not decayed because one or more of the conditions needed for decay are absent
• when parts of the organism are replaced by minerals as they decay
• as preserved traces of organisms, such as footprints, burrows and rootlet traces.
• from the hard parts of animals that do not decay easily

Question 6

Why is the fossil record incomplete?

Answer 6

• Many early forms of life were soft-bodied, which means that they have left few traces behind.
• What traces there were have been mainly destroyed by geological activity. This is why scientists cannot be certain about how life began on Earth.

Question 7

What do scientists use fossil to predict?

Answer 7

• how much or little different organisms have changed as life developed on earth

Question 8

How is resistant bacteria created?

Answer 8

1) Bacteria can evolve rapidly because they reproduce at a fast rate
2) Mutations of bacterial pathogens produce new strains
3) some strains might be resistant to antibiotics so are not killed
4) They survive and reproduce, so the population of the resistant strain rises
5) the resistant strain will then spread because people are not immune to it and there is no effective treatment

Question 9

How can the rate of the development of antibiotic-resistant strains be reduced

Answer 9

• doctors should not prescribe antibiotics inappropriately, such as treating non-serious or viral infections
• patients should complete their course of antibiotics so all bacteria are killed and none survive to mutate and form resistant strains
• the agricultural use of antibiotics should be restricted.

Question 10

Why can’t new antibiotics be developed to combat the resistant strains of bacteria

Answer 10

The development of new antibiotics is costly and slow. It is unlikely to keep up with the emergence of new resistant strains.

Question 11

when does extinction occur?

Answer 11

when there are no remaining individuals of a species still alive

Question 12

What can extinction be caused by?

Answer 12

1) Changes to the environment over geological time
2) new predators
3) new diseases
4) new, more successful competitors
5) a single catastrophic events eg. massive volcanic eruption

Question 13

Who classified animals in the Linnaean system?

Answer 13

Carl Linnaeus

Question 14

What did Linnaeus classify living things into?

Answer 14

Kingdom, phylum, class, order, family, genus and species

King Phillip Came Over For Good Soup

Question 15

When were new models of classification proposed?

Answer 15

• as evidence of internal structures became more developed due to improvements in microscopes
• the understanding of biochemical process progressed

Question 16

Who invented the three-domain system and why

Answer 16

Carl Woese due to evidence available from chemical analysis

Question 17

What is the three-domain system

Answer 17

• archaea (primitive bacteria usually living in extreme environments)
• bacteria (true bacteria)
• eukaryota (which includes protists, fungi, plants and animals).