Week 5: Adaptation to Environmental Stress Flashcards

1
Q

In complex traits, offspring tend to…

A

Resemble parents but regress towards the population mean

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2
Q

Offspring mean height lies between parental mean height and population mean height because of what 3 factors?

A
  1. During meiotic cell division, segregation and recombination break up combinations of genes leading to extreme phenotypes
  2. Parental phenotype is a result of both genetic and environmental factors
  3. Offspring phenotype is a result of both genetic and environmental factors
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3
Q

Define heritability

A

How well genetics can account for differences in one’s phenotypic expression ( a number between 0-1)
E.g. Height: heritability = 0.88 meaning genetic factors dictate this largely although environmental factors have some effect
E.g. Sleep: heritability = ~0.15 meaning it is largely environmental although some genetic effect is present

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4
Q

What is the estimated % of species loss per annum?

A

~0.25% per year

This is 5000 - 25,000 species a year dependant on how many species actually exist which is definitively unknown

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5
Q

Describe Bergmann’s rule

A

Larger species are found towards the poles (colder environments) with a decrease is size as one moves towards equatorial regions (warmer regions).
Low latitude organisms are smaller
High latitude organisms are larger

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6
Q

Why is this?

A

Surface area to volume ratio - larger organisms retain heat better and are thus better equipped cope with colder environments. This is a genetic adaption over time.

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