Quiz 2 (Lecture 8)

Question 1

life history

Answer 1

can be defined as the timing of, and investment in, growth reproduction, and survivorship
every patient has one

Question 2

patients have life histories that

Answer 2

have evolved and that continue to evolve

Question 3

human life history evolution now has both

Answer 3

medical causes and consequences

Question 4

life history has successfully explained

Answer 4

why organisms are small or large
why they mature early or late
why they have few or many offspring
why they must grow old and die

Question 5

Anything that influences ____ strongly influences ____

Answer 5

mortality and age of reproduction

Question 6

life histories result from

Answer 6

the interaction of extrinsic and intrinsic factors

Question 7

extrinsic factors influence

Answer 7

age- or stage-specific rates of mortality and reproduction (e.g. environmental factors like nutrition, disease, violence, medicine, public health…)

Question 8

intrinsic factors include

Answer 8

tradeoffs among traits (phylogeny, genetics, development, and physiology all involved)

Question 9

What does natural selection shape to maximize the positive difference between the benefits and costs of reproduction at different times?

Answer 9

age and size at maturity

Question 10

4 assumptions about costs and benefits for age & size at maturity

Answer 10

1. delaying maturity improves offspring survival
2. delaying maturity improves offspring number
3. earlier maturity shortens generation time
4. earlier maturity shortens the period of risk (risk of dying) before reproduction begins
   *organisms rarely live in unchanging environments

Question 11

_____ is often better than a fixed rule

Answer 11

A flexible compromise

Question 12

The reaction norm is

Answer 12

pattern of phenotypic expression of a single genotype across a range of environments
this idea that different phenotypes are produced by 1 genotype based on the environment

Question 13

predicted age & size at maturity optimums

Answer 13

in good environments: mature young and large
in bad environments: mature old and small

Question 14

historical study about age and size at maturity

Answer 14

when juvenile mortality decreases models predict the evolution of the reaction norm, favoring smaller size and earlier age at maturity

Question 15

Pygmy example

Answer 15

• being short is the product of the adaptation
• stop growing early in life and can have babies really early, high adult mortality

Question 16

when modern hygiene and medicine lower infant mortality rates,…

Answer 16

they reduce the evolutionary costs of earlier maturation, but the benefits of earlier maturation stay the same

Question 17

With the costs of earlier maturation reduced and the benefits unchanged, maturation shifts to

Answer 17

earlier ages
- the entire reaction norm moves down and to the left

Question 18

Framingham Heart study results in women

Answer 18

women are getting shorts and earlier reproduction age
-describes the biology of natural selection but culture is pushing women in other direction (have babies later)

Question 19

Age of maturation is determined by tradeoffs between

Answer 19

infant mortality and age of mother

Question 20

ex. of infant mortality and age of mother tradeoff

Answer 20

offspring of younger first-time mothers suffer higher mortality rates (that’s the tradeoff with juvenile mortality)

Question 21

what evolves is not a fixed value of a trait but the _______, the reaction norm

Answer 21

entire plastic repsonse

Question 22

patients are bundles of ___ that have been assembled by a process of tinkering with whatever was available that worked at the moment

Answer 22

tradeoffs
- not machines designed by an engineer
- not all of their parts can be replaced without consequences

Question 23

tradeoffs require two connections:

Answer 23

1. connections between 2 or more traits
2. connections between those traits and fitness

Question 24

A tradeoff only exists when

Answer 24

a change in one trait that increases fitness is associate with a change in another trait that decreases fitness