Lecture 14

Question 1

what is Vge

Answer 1

variance in the phenotypic trait that is due to different genotypes responding differently to environmental variation

Question 2

what is phenotypic plasticity?

Answer 2

a single genotype produces different phenotypes depending on the environment

Question 3

What is the reaction norm?

Answer 3

the phenotypes produced by a single genotype exposed to different environmental conditions. (phenotypic expression over different environments)

Question 4

How can evolution act on plasticity?

Answer 4

• evolution can act on plasiticty itself
• genotypes that are most plastic could be favored if individuals frequently experience different environments

Question 5

Is all plasticity adaptive?

Answer 5

• no
• think of humans who live at sea lebel go to high elebations, physiological chhanges are trigerred by the decrease in oxygen, over time this change causes medical problems

Question 6

What does phenotypic plasiticity allow oragnisms to do

Answer 6

allows organisms to respond to unpreditable changes, but also regularly occyring ones (ex. snowshoe hares with brown hair in summer, white hair in winter)

Question 7

what are polyphenisms?

Answer 7

• simple genetic polymorphisms can sometimes respond to their environment, and produce multiple discrete phenotypes
• the development of polyphenisms is often due to a threshold sensitivity in the environment

Question 8

What is the development of polyphenisms often due to in the environment?

Answer 8

the development of polyphenisms is often due to a threshold sensitivity to the environment

Question 9

what does it mean if the reaction norm for a genotype x environment interaction is parallel?

Answer 9

if they are parallel, all genotypes show same plasiticity

Question 10

what does it mean if two genotypes are superposed (on top of each other)?

Answer 10

all genotypes show same plasticity, and no genetic variation

VP=VE

Question 11

what does it mean if the lines are parallel but not superposed?

Answer 11

• genetic variation within an environment
• all genotypes show same plasiticity

VP=VG + VE

Question 12

what does it mean if the lines are NOT parallel (criss-crossing)?

Answer 12

• genetic variation within an environment
• genetic variation in plasiticity

VP=VG + VE + Vge

Question 13

how do scientists study and measure Vge?

Answer 13

scientists typically use experiements where they expose the same genotype to multiple environments