4.2 Variation & modern examples of Evolution Flashcards
(variation) what is variation?
differences in characteristics within and between species
(variation) what is interspecific variation?
variation or differences between different species
(variation) what is intraspecific variation?
differences between different organisms of the same species
(variation) give an example of interspecific variation:
rat has four legs and fur
snake has no legs and no fur
(variation) give an example of intraspecific variation?
people differ in height, eye colour and build
(variation) what are the two causes of variation?
environment
genes
(variation) give examples of environmental factors that can cause variation:
climate diet accident culture lifestyle diseases resources predators war
(variation) how is the flower colour of hydrangeas affected by the environment?
soil acidity
acid - blue flowers
alkaline - pink flowers
(variation) scars are an example of variation caused by what?
the environment
occur due to accident or disease
(variation) environment - a plant in the sun is more likely to do what?
grow than one in the shade
(variation) genetic variation can be due to what 5 factors?
alleles mutation meiosis sexual reproduction chance
(variation) genes have different alleles, which produce what?
differences in characteristics e.g. there are 3 alleles for blood group depending on combination 1 of 4 groups can be produced
(variation) what are mutations?
changes in the DNA sequence which can affect the proteins coded for affecting characteristics
(variation) when can a mutation be passed onto the offspring and inherited?
if it occurs in the gametes
(variation) how can variation occur in meiosis?
independent assortment of homologous chromosomes
crossing over