B15 - Genetics and Evolution

Question 1

what are fossils

Answer 1

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

Question 2

how can fossils be formed

Answer 2

• from parts of organisms that have not decayed because one or more of the coniditons needed for decay are not pressent
• when parts of the organism are replaced by minerals as they decay
• as peserved traces of organisms, such as footprints, burrows and rootlet traces

Question 3

why cant scientists be cartein about how life began on earth

Answer 3

because traces have been destroyed by geological activity, earth was soft-bodied - means they leave few traces behind

Question 4

what can we learn from fossils

Answer 4

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

Question 5

what is extinction

Answer 5

when no remaining individual of a species is still alive

Question 6

what are some factors that may contribite to the extinction of species

Answer 6

• overhunting
• new predators
• new diseases
• changes in enviroment
• new, more sucsessfull competitors

Question 7

what does bacteria do

Answer 7

can evolve rapidly becuase they produce at a fast rate

Question 8

development of a bacterial population resistant to antibiotics is an example of natural selection

Answer 8

• mutations of bacterial pathogend produce new strains
• some strains might be reisistant to antibiotics so arent killed
• they survive and reproduce, so population of the reisitant strains rises
• the resistant strain will then spread becuase people are not immune to it and there is no effective treatment

Question 9

what is MRSA

Answer 9

is a bacteria resistant to antibiotics

Question 10

how can you reduce the rate of development of antibiotic resistant strains

Answer 10

1. doctors should not prescribe antibiotics inpropriately, e.g for non-serious or viral infections
2. patients should complete their course of antibiotics so all bacteria are killed and none survive to mutate and form resistant strains
3. agricultural use of antibiotics should be restricted

Question 11

what is the new development of new antibiotics like

Answer 11

• costly and slow
• unlikely to keep up with te emergence of new resistant strains

Question 12

what did Carl Linneaus develop

Answer 12

the system of living thing sbeing classified into groups depending on their structure and characteristics

Question 13

what are the groups that Linneaus developed

Answer 13

• kingdom
• phylum
• class
• order
• family
• genus
• species

Question 14

what happened as the evidence of internal structure became more develop

Answer 14

• improvements in microscopes
• improvements in the understanding of biochemical processes
• new models of classification were proposed

Question 15

what are the three domain systems developed by Carl Woese, what are the organisms divided into

Answer 15

• Archaea (primitive bacteria usually living in extreme enviroments)
• Bacteria (true bacteria)
• Eukaryota (includes protits, fungi, plants and animals)

Question 16

what are evolutionary trees

Answer 16

a method used by scientists to show how they belive organisms are related, they use current classification data for living organisms and fossil data for extinct organisms

Question 17

what is the theory of evolution by natural selection

Answer 17

widely accepted

Question 18

what is the evidence for Darwins theory

Answer 18

• now available as it has been shown that characteristics are passed on to offspring in genes
• further evidence in the fossil record and the knowledge of how resistance to antibiotics envolves in bacteria