6. Nature of Biological Variation Flashcards
define macroevolution
evolutionary change over long periods of time on a large scale
give 2 examples of macroevolution
mass extinctions
new taxonomic groups
adaptive radiation
define microevolution
change either at or below species level
give 2 examples of microevolution
natural selection
-individuals best equipped to the environment survive
Cuban tree snails
-in some locations a lighter shell is more advantageous and enables survival
what is karotyping
pairing and ordering chromosomes
what is parthogenesis
reproduction via unfertilised eggs
no genetic input from males
occurs either if or when needed
give an example of vegetative reproduction
plant runners
by what 3 ways are offspring genetically different from their parents
1) independent assortment of chromosomes in meiosis
2) exchange in DNA when chromosomes cross over
3) random fertilisation
what is a disadvantage of asexual reproduction
less variation in offspring
what is polyploidy
when there are multiple sets of chromosomes
what is autopolyploidy
during anaphase when the chromosomes separate via spindle fibres, one does not split meaning one cell ends up with double
what is allopolyploidy
when two different related species interbreed and the chromosome number doubles
what type of mutation caused sickle cell anaemia
single point mutation
what are the consequences of sickle cell anaemia
changes in protein structure of the haemoglobin resulting in sickle shaped RBCs
what allele combination for sickle cell anaemia is:
fatal
useful
fatal= HsHs useful= HnHs
