Adaptation to Environmental Stress

Question 1

quantitative traits

Answer 1

a complex trait in which the phenotype is measured along a continuum with only small intervals between similar individuals (height)

Question 2

complex traits are

Answer 2

affected by the environment (poor nutrition leads to shortness)

Question 3

environmental risk factors

Answer 3

increase the likelihood of developing a particular disease. junk food increases risk of obesity

Question 4

inbred lines

Answer 4

a true, homozygous strain. individuals are genetically identical, differences are due to the environment

Question 5

complex traits are also

Answer 5

affected by multiple genes

• skin colour
• distribution of phenotypes often follow a normal distribution

Question 6

genetic and environmental effects can interact in unpredictable ways

Answer 6

when fed on a high fat diet, mouse A becomes obese, mouse B does not
- need to know environment and genotype to predict phenotype

Question 7

phenotype plasticity

Answer 7

same genotype but different phenotype because of environment (twins)

Question 8

genotype-by-environment interaction

Answer 8

unequal effects of the environment on different genotypes, resulting in different phenotypes

Question 9

resemblance among relatives

Answer 9

offspring resemble parents but show regression to the mean in complex traits (not as tall as tall parents)

• segregation and recombination break up genes of extreme phenotypes
• environmental factors that influenced parent are to inherited

Question 10

heritability

Answer 10

in a population, the proportion of the total variation in a trait that is due to genetic differences among individuals
- are differences due to environment of genes

Question 11

cultural transmission

Answer 11

the transfer of information among individuals through learning or imitation - rich children from rich parents

Question 12

types of twins

Answer 12

identical (monozygotic) twins

fraternal (dizygotic) twins

Question 13

twin studies

Answer 13

learn about complex traits

• differences between fraternal twins - genetic or environmental
• differences between identical twins - environmental

Question 14

concordance

Answer 14

percentage of cases in which both members of a pair of twins show the trait when it is known that at least one shows it.
- high concordance in identical twins but not identical (probably genetic)

Question 15

human influence on evolution

Answer 15

• human activities have reduced quality and size of habitats (support less species)
• 5000-25000 species are lost a year (0.25%)
• 30% of ocean fisheries have declined by 90%
• invasive species
• caused natural selection with drugs like antibiotics
• 1/3 amphibians near extinction
• evolution must respond fast to climate change - la Nino and el Nino may be more extreme and more frequent

Question 16

evolutionary adaptation

Answer 16

heritable changes to the nucleotide sequence

Question 17

Bergman’s rule

Answer 17

larger species are in colder places, smaller in warmer places

Question 18

tests for signatures of climatic adaptation

Answer 18

1. study of latitudinal clines - species populations have adapted slightly to different latitudes
2. lab-based experimental evolution - selecting individuals and changing species overtime