Test 3, Deck 3 Flashcards
In ducks and chickens, eggs of intermediate weight have more hatching success. What mode of selection is it?
Stabilizing selection
Fossil evidence indicates that the average size of bears in Europe increased with each glacial period. What mode of selection is it?
Directional selection, one extreme favored
Snails that live among tan rocks covered with white barnacles are either white or tan. Snails neither white nor tan or more likely to be eaten. What mode of selection is it?
Disruptive selection: 2 extreme favored
Human newborns who are under 5 lb or over 10 lb are less likely to survive than babies between 5 lb and 10 lb. What mode of selection is it?
Stabilizing selection
Finch bird population have variety of beak size/shape. In an island, the only food available in a drought was wood boring insects and seeds in cactus. Longer beaks could open the cactus seeds and wider beaks could strip off the tree bark. What mode of selection is it?
Disruptive selection
Determine the frequency of the recessive alleles in a population with 20 AA, 100 Aa and 80 aa.
0.65
Calculate q squared for a population with 100 AA, 40 Aa and 60 aa.
0.16
Determine the frequency of dominant allele in 20 AA, 100 Aa and 80 aa.
0.35
Calculate p squared for a population with 20 AA, 100 Aa and 80 aa.
0.12
Determine the frequency of the homozygous dominant phenotype 40 AA, 60 Aa, 100 aa.
0.20
Calculate p for population with 20 AA, 100 Aa, 80 aa.
0.3162
determine the frequency of the homozygous recessive genotype in 100 AA, 40 Aa, 60 aa.
0.30
Calculate q for a population of 20 AA, 100 Aa and 80 aa.
0.6325
Calculate p+q for 60 AA, 100 Aa, 40 aa.
0.9952=1
Which values need to be calculated to determine if population is in equilibrium.
A Real frequency of recessive allele
B Real frequency of homozygous recessive genotype
C p squared
D q squared
E Real frequency of dominant allele
F q
F, A, B
In two parts in Africa, 90% elephants were slaughtered for their tusks, most female are now born without tusks. What is the mechanism of evolution?
Natural selection bc not random
Ancestors of indigenous people arrived in small numbers by crossing the Bering strait. Type B blood is highest in Asia, but nearly absent in the indigenous population of America. What is the mechanism of evolution?
Genetic drift ( founder’s effect)
How does a modification help an organism adapt?
The change in alleles will change the phenotype of the organism and it will be more fit to survive if the change is advantageous.
How are different species determined?
Depends on the concept analyzed, Ecological: same ressources/area, Phylogenetic: same ancestry and genetics, Biological: same gene pool and able to interbreed and create fertile offsprings and Morphological: similar individuals
What triggers change in allele frequency?
Gene flow, genetic drift, natural selection (change in environment) or mutations.
