4 - Classification and Evolution

Question 1

what is genetic diversity?

Answer 1

the number of different alleles in a population

Question 2

how does natural selection work?

Answer 2

• random mutation results in new alleles
• new selection pressure favours animal with these advantageous alleles
• these survive and reproduce, pass on advantageous alleles to offspring
• new allele increases in frequency
• increase gene pool

Question 3

describe directional selection

Answer 3

changed selection pressure, so distinct advantageous allele. curve moves to the right or left, and could become new species

Question 4

describe stabilising selection

Answer 4

selection pressure favours intermediate phenotype, so graph becomes longer and thinner

Question 5

describe disruptive selection

Answer 5

groups from an original singular original population are exposed to different selection pressures, as different alleles are advantageous

Question 6

what is true of all types of selection?

Answer 6

always reduction in genetic variation

always in response to selection pressure

Question 7

what defines a species?

Answer 7

when two organisms in that species can produce fertile offspring

Question 8

why is courtship necessary?

Answer 8

• ensure the animals are the right gender
• right species
• both sexually mature and fertile

Question 9

what is a phylogenetic classification system/

Answer 9

arranges species into groups based on their evolutionary origins and relationships. these groups do not overlap

Question 10

order of the hierarchy

Answer 10

domain
kingdom
phylum
class
order
family
genus
species

Question 11

what is a species’ name made up of?

Answer 11

its genus and species

Question 12

how can genetic diversity be compared?

Answer 12

• frequency of measurable or observable characteristics
• base sequence of DNA
• base sequence of mRNA
• amino acid sequence of proteins encoded by DNA and mRNA