Lab Manual Flashcards
How do you measure selection?
measure target trait frequency and reproductive success of individuals with variations of target trait
What is absolute fitness?
total number of an offspring of an individual
What is relative fitness?
total number of offspring divided by average number of offspring produced by a population
What kind of graph would show directional selection?
positive linear line = high fitness, negative linear line = low fitness
What kind of graph would show stabilizing selection?
positive parabola, intermediate values favourable
What kind of graph would show disruptive selection?
negative parabola, extreme values favourable
What kind of graph would show no selection?
flat line
Which length growing season would plants be more successful in before a drought?
long growing season
Which length growing season would plants be more successful in after a drought?
short growing season
What is a mutualism?
an interaction between two species where they both benefit
What is the mutualism between medicago and rhizobia?
rhizobia convert N2 into NH3 for medicago which grow in nitrogen poor soil and are endocytosed to form nodules on their root systems using a flavonoid/nod factor interaction
What are intermediate nodules?
nodules that can continue to grow in size but are unable to reproduce
What are determinate nodules?
nodules that stop growing about a week after infection
Which rhizobial genes are involved in symbiosis?
symbiosis island, located in plasmid, can be horizontally transferred
What is a mechanism for detecting cheating rhizobia?
partner-choice: allocating less resources to those who weren’t fixing nitrogen efficiently
for the plant, rewarding those who did
How is partner choice detected?
biomass of non-fixing rhizobia nodules are smaller than those that do
Which rhizobia are antibiotic resistant/susceptible?
mutualists are susceptible and can only grow outside zone of inhibition, cheaters are resistant and can grow around antibiotic disc
What medical-rhizobia interactions are seen in low nitrogen environments?
more nodules formed because plants need to take the chance of engulfing cheaters to get nitrogen
What medical-rhizobia interactions are seen in high nitrogen environments?
less nodules formed because plants can get nitrogen for themselves, less cheaters because rhizobia have less at stake and higher chances of living comfortably
What is inclusive fitness?
sum of direct and indirect fitness
What is greenbeard selection?
altruistic behaviour dedicated to unrelated individuals with similar traits
What behaviour can be seen in yeast individuals carrying the FLO1 locus?
yeast cells will flocculate, making them less susceptible to chemical and environmental stress
If all strains tested were to flocculate, which plates would they grow on?
A: YPD; B: YPD, G418; C: none
If the strains tested were to flocculate only with kin, which plates would they grow on?
A: YPD; B: YPD, G418; C: none
