BIO220 Lecture 6

Question 1

What is the ultimate question when it comes to aging?

Answer 1

Why did aging evolve?

Question 2

What are some ways to increase lifespan?

Answer 2

1. Eat ACE vit
2. Exercise
3. Diet restrictions
4. Wealthy

Question 3

what does vit E do?

Answer 3

Increase lifespan (maybe?)

Question 4

What does exercise do?

Answer 4

Reduce heart disease

Question 5

What does diet restrictions do?

Answer 5

eating less = live longer

Question 6

How does money impact aging?

Answer 6

More wealthy = live longer

Question 7

Free radicals

Answer 7

Molecules with at least 1 unpaired electron

Question 8

What do free radicals do?

Answer 8

Attack & modify macromolecules
Oxidation of DNA, lipids, proteins
-> Damage body and speed up aging

Question 9

How do we defend against free radicals?

Answer 9

some AA act as antioxidants

Question 10

What can act as antioxidants?

Answer 10

Some AA in the body

Vit E and C

Question 11

Darwinian Demon

Answer 11

Ideal organism that can maximize every component of fitness without constraints

Question 12

What does the Darwinian Demon prove?

Answer 12

Nothing can do that, so there must be constraints / trade-offs for biological systems

Question 13

Tradeoffs happen between…

Answer 13

Display size / morphological traits
Foraging rate / behavioural traits
Longevity / life history traits

Question 14

Display size is a ____ trait

Answer 14

morphological

Question 15

Foraging rate is a ____ trait

Answer 15

behavioural

Question 16

Longevity is a ____ trait

Answer 16

life history

Question 17

Cost of high reproductive rate

Answer 17

Accelerates senescence (die earlier)

Question 18

Why does high reproduction shorten life-span?

Answer 18

A lot of effort, time, resources used for reproduction that can otherwise be used to maintain body

Question 19

How was the hypothesis that high reproduction shorten life-span tested?

Answer 19

In waterstriders.
Manipulate food supply to control reproductive rate.
Those who laid more eggs lived 1/2 as long as those who didn’t lay many eggs.

Question 20

What is the order in which reproductive senescence occurs?

Answer 20

1. Eggs fail to hatch
2. Eggs fail to develop
3. Reproduction stops
4. Death

Question 21

What type of quality of eggs in waterstriders can be seen as they get older?

Answer 21

1. Developmentally arrested

2. Abnormally developed

Question 22

What are some methods of measuring cost of reproduction?

Answer 22

• Diet restrictions
• Egg addition (give more eggs to some mothers)
• Removal of oviposition sites (can’t lay eggs)
• Delay of reproduction (select for these types)

Question 23

What were the results of the genealogical study done on British aristocracy?

Answer 23

Mothers before 1700 had 2.8 offspring, and had higher probability of death every year.

Mothers after 1700 had 2.0 offspring, and had lower probability of death.

Age of death decreased with increasing number of offspring.

Question 24

What is an alternate explanation for the genealogical study done on British aristocracy?

Answer 24

Better sanitation and medical care after 1700

Question 25

Why do female mammals typically outlive males?

Answer 25

Cost of male competition

Question 26

What are the 2 theories of senescence?

Answer 26

1. Mutation accumulation | 2. Antagonistic Pleiotropy

Question 27

What does MA and AP have in common?

Answer 27

Relies on the assumption that strength of selection declines with age

Question 28

MA

Answer 28

Mutation accumulation

Question 29

AP

Answer 29

Antagonistic pleiotropy

Question 30

Define MA

Answer 30

Bad mutations with age-specific effects that don't happen until you're older. Natural selection can't act on this b/c you have already reproduced, so no point.

Question 31

Define AP

Answer 31

Pleiotropic genes that have pos effect earlier in life will be selected for despite it having neg effects later in life

Question 32

Even in a population without senescence, survival probably decreases with age because...

Answer 32

``` External factors (predators, accidents, parasites). 10% externally imposed mortality per year ```

Question 33

Why does selection strength decrease as you get older?

Answer 33

1. Offspring already has that disease, so no point in selection 2. Many individuals die before expressing

Question 34

Evidence for MA?

Answer 34

Single gene effects: 1. Severe diseases that are present pre-reproduction = 7% 2. Severe diseases that are present post-reproduction = 93%

Question 35

How was cost of reproduction tested for in fruit flies? (Michael Rose)

Answer 35

Normal fly which reproduces lived shorter lives than those that were manipulated to reproduce less

Question 36

What was the result of Rose's experiment in terms of breeding for longevity?

Answer 36

O lines lived longer than N lines (both males and females)

Question 37

What was the result of Rose's experiment in terms of AP?

Answer 37

O lines reproduce less early life, reproduce more late life. | Increased late fecundity comes at a cost to early fecundity.