Module 4- Classification and Evolution

Question 1

what were darwin’s 4 main observations?

Answer 1

-offspring appear similar to their parents
-no two individuals were identical
-organisms have the ability to produce large numbers of offspring
-populations in nature tend to remain fairly stable in size

Question 2

what are fossils?

Answer 2

the remains or impressions of prehistoric plant/animals preserved in rocks

Question 3

what is a homologous structure?

Answer 3

structure that appears superficially different in different organisms but has the same underlying structure

Question 4

what is phylogeny?

Answer 4

based on the closeness of evolutionary relationships

Question 5

what were early classification systems based on?

Answer 5

physical characteristics

Question 6

what is classification?

Answer 6

grouping organisms into groups based on similarities and differences

Question 7

what is the relationship between classification and phylogeny?

Answer 7

modern classification reflects phylogeny

Question 8

what can be learnt from fossils?

Answer 8

fossils deeper in the ground are older than
those near the surface and show that organisms change over time

Question 9

what is intraspecific variation + example?

Answer 9

within species e.g. human height and eye colour

Question 10

what is interspecific variation + example?

Answer 10

between species e.g. mouse has 4 legs bird has 2 legs

Question 10

what is the formula for a histogram?

Answer 10

frequency density=frequency/class width

Question 11

what is natural selection?

Answer 11

process by which organisms best suited to their environment survive and reproduce passing on their characteristics to their offspring through their genes

Question 12

how is genetic variation caused?

Answer 12

meiosis

Question 13

what is the process of natural selection?

Answer 13

-variations exist within a population
-those with the characteristics best suited to the environment survive and reproduce
-genes for best characteristics are passed onto offspring

Question 14

how does evolution in some species have implications for human populations? (antibiotics)

Answer 14

-MRSA has developed resistance to many antibiotics
-bacteria replicate rapidly which can cause mutations in genes resulting in alleles that provide resistance to antibiotics
-when exposed to antibiotic resistant bacteria survive and continue to reproduce passing on the allele for resistance to offspring
-non resistant don’t survive so resistant population increased

Question 15

Discuss the implications of the over-use of antibiotics when people do not show symptoms?

Answer 15

-when exposed to antibiotic
most-resistant bacteria survive and continue to reproduce to make a
resistant population
-over many generations there is an increase in proportion of resistant bacteria so antibiotic becomes ineffective