Lec 12 slides

Question 1

issue with weeds and herbicides

Answer 1

-weeds start adapting to herbicides and evolve resistance to them

Question 2

where does resistance come from

Answer 2

1) pre-existing genetic variation in the pop.
2) new mutations
-in very large pop. new, simple
mutations introduced at high rate
3) gene flow
-‘epidemic spread’ of resistance from
one region to the next

Question 3

outcrossing vs selfing weeds

Answer 3

outcrossing weeds have MORE pre-existing resistance variation than selfing weeds
-more resistance and increased genetic variation

Question 4

what does resistance evolve through

Answer 4

pre-existing variation, long-distance dispersal, and new mutations in local pop.

Question 5

can herbicide resistance be stopped

Answer 5

1. multi-herbicide treatment
   -makes new adaptations less likely
   -requires more complex adaptation
2. rotation of different kinds of herbicides
   -weeds regularly hit by different selection pressures
   -but: could select for generalized resistance

Question 6

evolution in medicine, how can we slow evolution of HIV resistance

Answer 6

-single mutations unlikely to confer resistance to multiple drugs with different mechanisms of action
-lower viral loads make multiple mutations less likely

Question 7

how are humans causing rapid environ. change

Answer 7

-loss of habitat
-habitat fragmentation
-altered abiotic conditions
-temp, precip, pH, salinity, chemical
pollutants
-altered biotic composition
-transport of species
-invasive species

Question 8

extinction

Answer 8

permanent elimination of a species

Question 9

_____ is a normal evolutionary process

Answer 9

evolution

Question 10

genetic issues in conservation biology

Answer 10

-loss of genetic diversity
-loss of heterozygosity
-inbreeding depression
-fixation of deleterious alleles
-inability of pop. to adapt

Question 11

probability of evolutionary rescue from adaptation, depends on:

Answer 11

pop. size, beneficial mutation rate how much fitness was reduced