evolution

Question 1

mutation

Answer 1

a random change to genetic material
- spontaneous and the only source of new alleles

Question 1

evolution

Answer 1

the changes in organisms over generations as a result of genomic variations

Question 2

why is a variation important?

Answer 2

• makes it possible for plants and animals to become better adapted to their environment

Question 3

adaptations

Answer 3

inherited characteristics that make organisms well suited to survival in their environment or niche

Question 4

advantage

Answer 4

• better chance of surviving to reproduce
  passes on their alleles to their offspring and advantage to the next generation

Question 5

disadvantage

Answer 5

• will not pass if lacking beneficial sequences of DNA therefore wont pass their DNA to next generation
• frequency of sequences of DNA which confer a deleterious will reduce in population

Question 6

natural selection

Answer 6

the non random increase in frequency of DNA sequences that increase survival
ALSO
the non random decrease of frequency of deletrious sequences

Question 7

changes in phenotype frequency result in…

Answer 7

stabilisting, disruptive and directional selection

Question 8

deleterious sequences

Answer 8

when the frequency of some DNA sequences increases in population because they are selected for - other DNA sequences decrease in population because they are selected against
- can be lethal when caused by mutations and offsprings wont survive and not pass on these deletreious genes to their offspring

Question 9

phenotype frequency

Answer 9

the number of indivisuals in a population that have a specific obsevable trait
- change as a result of selection overtime

Question 10

selection pressures

Answer 10

external agents which affect and organisms ability to survive in a given environment

Question 11

stabilising selection

Answer 11

when an average phenotype is selected for and extremes of the phenotype range are selected agaisnt
- gives an advantage to indivisuals that possess the average phenotype
- maintains the mean value in a population and the best adapted genotypes

Question 12

directional selection

Answer 12

when one extreme of the phenotype is selcted for
- favours alleles at one phenogenetic extreme in response to change in environment pressure
- causes progressive change towards a characteristic over generations

Question 13

disruptive selection

Answer 13

when 2 or more phenotypes are selected for
- favours 2 extreme forms of a characteristic
- occurs when 2 different habitats/types of resource become available
- conditions favour more than one phentotype within a population
- population gets split into 2 distinct groups (sub-populations) each with its own mean value

Question 14

inheritance

Answer 14

the passage of genetic information from parent to offspring

Question 15

vertical gene transfer

Answer 15

where genes are transferred from parent to offspring as a result of sexual or asexual reproduction

sexual - offspring genetically different / different genomes > will display combo of maternal and paternal phenotype

asexual - no gametes produced, produces hundreds of offspring over short time, offspring is genetically identical to parent eg identical genomes

Question 16

horizontal gene transfer

Answer 16

where genes are transferred between individuals in the same generation