Lecture 12: Applied Evolution

Question 1

What is the issue of pests and evolution

Answer 1

we use chemicals to combat pests and pathogens

we create strong selective pressure for resistance since a resistant genotype has a fitness advantage

Question 2

How much crop yield loss is attributed to weeds

Answer 2

approx 34%

Question 3

How are weeds detrimental

Answer 3

land is not being used efficiently due to weeds competing for crops, light, nutrients, and space

Question 4

How much money is lost in the US from weeds

Answer 4

26 billion

Question 5

what is profs least fav week

Answer 5

canada fleabane; horseweed
pretty much all resistant to glyphosate

Question 6

Three places where resistance comes from

Answer 6

1) pre-existing genetic variation in the population

2) new mutations; in very large populations new, simple mutations may be introduced at a high rate

3) gene flow; epidemic spread of resistance from one region to the next

Question 7

How is the best management strategy determined

Answer 7

depends on how resistance tends to evolve

Question 8

What is the difference in pre-existing resistance in different reproductive plants

Answer 8

outcrossing plants have more genetic variation that helps them evolve resistance compared to selfing plants

Question 8

What is the most likely way glyphosate resistance arose

Answer 8

gene flow

Question 9

Three ways resistance evolves

Answer 9

1) pre-existing variation
2) long-distance dispersal
3) new mutations in local populations

Question 10

Two ways herbicide resistance can be stopped

Answer 10

1) multi-herbicide treatment
2) rotation of different kinds of herbicides

Question 11

Pro/con of multi-herbicide treatment

Answer 11

makes new adaptation less likely

requires more complex adaptation

Question 12

Pro/con of rotating different kinds of herbicides

Answer 12

weeds are regularly hit by different selection pressures

could select for generalized resistance

Question 13

Define evolutionary rescue

Answer 13

the increase in population following a low point of demographic decline after environmental change

Question 14

Two examples of environmental change causing demographic decline in weeds

Answer 14

application of herbicide, climate warming

Question 15

How many deaths annually are caused by malaria

Answer 15

600 000

Question 16

What is the major prevention strategy of malaria

Answer 16

insecticides; selects for resistance in mosquitos

Question 17

What treatment can avoid resistance of evolution in mosquitos

Answer 17

tailor insecticide application to knowledge of mosquito generation times and spatial distributions

Question 18

What are four approaches to malaria prevention in mosquitos

Answer 18

1) responsive alternation

2) mosaic

3) periodic application

4) combination

Question 19

Describe responsive alternation

Answer 19

selects for resistant genotype in first three generations, in fourth generation other insectiside is used

nnot very effective for mosquitos

Question 20

Describe mosaic

Answer 20

spatially clustered application of different insecticides

scale of patch determines effectiveness of treatment

small= wipe out quickly
large= selects for success of different mosquitos in different places

Question 21

What is the best insecticide approach for mosquitos

Answer 21

combination treatment

Question 22

what were the results of less aggressive drug treatment of malaria

Answer 22

1) less evolution of resistance
2) reduced infectiousness
3) similar health outcomes

Question 23

What is the issue with higher doses of malaria drugs

Answer 23

high doses lead to strong selection to resistance

Question 24

How do current HIV drugs work

Answer 24

hinder virus replication, but cannot eradicate virus from latent reservoirs in the body we use evolution to manage HIV rather than eliminate it

Question 25

Why can HIV never be fully eliminated

Answer 25

infected people have latent reservoirs of the virus

Question 26

What are the two major strategies to manage HIV

Answer 26

1) multi-drug cocktail 2) Evolutionary toggling

Question 27

Two benefits to using the multi-drug cocktail to treat HIV

Answer 27

1) single mutations are unlikely to confer resistance to multiple drugs with different mechanisms of action 2) lower viral loads make multiple mutations less likely

Question 28

What is an evolution-informed approach to HIV treatment

Answer 28

using a multi-drug cocktail to slow the process of evolution of the drug

Question 29

Describe three steps to the process of evolutionary toggling

Answer 29

1) Once resistance evolves, stop taking drug 2) Since resistance has a cost, non-resistant forms will then dominate 3) Then re-apply drug, reducing virus levels

Question 30

What does evolutionary toggling take advantage of

Answer 30

the fitness cost that comes with developing resistance

Question 31

What does cancer treatment select for

Answer 31

drug-resistant tumors

Question 32

What changes in chemotherapy

Answer 32

certain alleles genes conferring resistance increase in frequency after treatment

Question 33

What treatment accounts for evolution in cancer treatment

Answer 33

Using a lighter does to knock out some sensitive cells but not all so that the resistant cells do not dominate and become entirely resistant

Question 34

What are the two evolutionary takeaways for cancer treatment

Answer 34

1) strong, prolonged selection pressures using the same chemotherapy drugs 2) cycling drugs, multidrug cocktails, lower doses of drugs

Question 35

Three examples of humans causing rapid environmental change

Answer 35

1) loss or fragmentation of habitat 2) altered abiotic conditions (temp, pH, chemicals) 3) Altered biotic composition (transportation of species, invasive species and diseases_

Question 36

Example of an endangered species and why we caused it

Answer 36

Hawaiian honeycreepers, due to humans introducing a form of bird malaria to the Hawaiian islands

Question 37

What is the Chytrid Fungus epidemic

Answer 37

infects the skin of amphibians, die within a few months because of osmotic regulation problems

Question 38

Why do amphibians need their skin

Answer 38

breath and get water

Question 39

Why are amphibians suddenly becoming infected by chytrid fungus

Answer 39

humans moved the fungus from one region where amphibians were locally adapted to it to the rest of the globe where they were not adapted

Question 40

Five genetic issues in conservation biology

Answer 40

1) loss of genetic diversity 2) loss of heterozygosity 3) inbreeding depression 4) fixation of deleterious alleles 5) inability of populations to adapt

Question 41

What three factors does the probability of evolutionary rescue depend on

Answer 41

1) population size 2) beneficial mutation rate 3) how much fitness was reduced

Question 42

What level of adaptability do we want for a population to survive

Answer 42

want a value of 1 value of 0 goes extinct

Question 43

What is on the wild type fitness axis

Answer 43

measures what amount of fitness has been lost in the population before and after chytrid 1-s

Question 44

What is the mutation-supply rate `

Answer 44

How many mutations are entering the population influenced by beneficial mutation rate and population size presented on a log scale

Question 45

What is some possible evidence for evolutionary rescue in frogs

Answer 45

survivor populations have adapted resistance to fungus particularly diasporus diastema