Life History Evolution - 4 | Reproduction and Ageing

Life History Evolution | 4. Reproduction and Ageing - Bart Pannebakker
Variation in lifespan
Extrinsic mortality
Intrinsic mortality
GxE interactions
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Slide 1: Tekstslide
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Life History Evolution | 4. Reproduction and Ageing - Bart Pannebakker
Variation in lifespan
Extrinsic mortality
Intrinsic mortality
GxE interactions

Slide 1 - Tekstslide

I. Wat are the variations in lifespan?
II. Why is there such tremendous variation?
III. What causes ageing?
IV. Why do we age?

Slide 2 - Open vraag


Slide 3 - Tekstslide


Slide 4 - Tekstslide


Slide 5 - Tekstslide

Slide 6 - Tekstslide

Slide 7 - Tekstslide

Why do bats live so much longer than other mammals of the same size?
Because they're dormant for a large period of the year and they don't age in that period.
Ability to fly is the key, it gives them a greater chance to survive.

Slide 8 - Quizvraag

What is the right word for:

A balance between selection to increase the number of reproductive events per lifetime and effects that increase the intrinsic source of mortality with age. (Mortality rate should increase with age.)
Reproductive lifespan
Mortality rate

Slide 9 - Quizvraag

Slide 10 - Tekstslide

Slide 11 - Tekstslide



Slide 12 - Tekstslide

How do these species differ in their reproductive strategie? 
Semelparity vs Iteroparity

Slide 13 - Tekstslide

When is a single reproductive event in a lifetime favourable?

Slide 14 - Tekstslide

When is a single reproductive event in a lifetime favourable?

Slide 15 - Open vraag

Lack's principle

Cole's paradox

The Malthusian Trap

William's principle

For an annual species, the absolute gain in intrinsic population growth which could be achieved by changing to the perennial reproductive habit would be exactly equivalent to adding one individual to the average litter size. 101 offspring at age 1 = 100 offspring forever
This occurs when population growth outpaces agricultural production, causing famine or war, resulting in poverty and depopulation.
The clutch size of each species is a product of natural selection which favours the largest number of offspring that parents can provide care. 
Refined Lack's principle: the effort spent on reproduction must be worth the cost, compared to the long-term reproductive fitness of the individual.

Slide 16 - Sleepvraag

What was the answer to Coles paradox?
Semelparity is always favourable
When parents have better extrinsic survival odds than juveniles, investing in intrinsic adult survival becomes worth it
Iteroparity is always favourable
If everyone is equally unsafe, then selection pressure is towards semelparity (e.g. stressfull conditions; high predation)

Slide 17 - Quizvraag

is the population size at time t

Slide 18 - Sleepvraag

Longer reproductive lifespan | Mean mortality rates

Which one of the answers is correct?
When adult mortality is low, than is semelparity favoured
When juvenile mortality is low, than iteroparity is favoured
When neither of them are low, then iteroparity is favoured
When juvenile mortality is low, than semelparity is favoured

Slide 19 - Quizvraag

Slide 20 - Open vraag

Slide 21 - Sleepvraag

Slide 22 - Sleepvraag


Biological bet hedging occurs when organisms suffer decreased fitness in their typical conditions in exchange for increased fitness in stressful conditions. Biological bet hedging was originally proposed to explain the observation of a seed bank, or a reservoir of ungerminated seeds in the soil.

What is not an example of bet-hedging?
foraging behavior in bumble bees
an annual plant's fitness is maximized for that year if all of its seeds germinate. However, if a drought occurs that kills germinated plants, but not ungerminated seeds, plants with seeds remaining in the seed bank will have a fitness advantage. Therefore, it can be advantageous for plants to "hedge their bets" in case of a drought by producing some seeds that germinate immediately and other seeds that lie dormant.
female multiple mating
All are examples

Slide 23 - Quizvraag

What is the definition of ageing?
Late-life decline in individuals fertility and probability of survival
Multiple reproductive cycles over the course of its lifetime. All birds, most reptiles, virtually all mammals, most fish. Most mollusca, many insects.r and k-selection strategies.
Fitness components: Traits or characteristics that affect the life table of an organism, and can be imagined as various investments in growth, reproduction, and survivorship.
Ageing is the total effect of those intrinsic changes that accumulate in the course of life that negatively affect the vitality of the organism, and that makes it more susceptible to the factors that can cause death

Slide 24 - Quizvraag

Slide 25 - Sleepvraag

Welk λ - getal hoort hierbij?
λ 1.0
λ -1.0
λ 0.5
λ 1.2

Slide 26 - Quizvraag

Why do organisms age?

Slide 27 - Open vraag

If there's a negative correlation between temperature and longevity;

What predictions could you make for these longevity of species with climate change?
The lifespan of organisms isn't effected
The lifespan of organisms shortens
Traits or characteristics that affect the life table of an organism, and can be imagined as various investments in growth, reproduction, and survivorship.
A tradeoff is where one thing increases, and another must decrease.

Slide 28 - Quizvraag

What is NOT correct about telomeres?

- Cell division is limited by telomeres length (limited number of devisions);
- In the wild there's no correlation between mean life span and mean telomere length;
- A telomere is a region of repetitive nucleotide sequences associated with specialized proteins at the ends of linear chromosomes;
A telomere lengthens with increasing lifespan.

Slide 29 - Quizvraag

Oxidative stress theory of ageing
additional sources: e.g. NADPH oxidase, 5=lipoxygenase, xanthine, oxidase, peroxisomes, UV, heat -->
< -- functional decline
Oxidative damage
lipids | proteine | nucleic acids
(e.g. singlet oxygen, superoxide anion, hydrogen peroxide, hydroxyl radical

Slide 30 - Sleepvraag

What theory applies for naked mole rats?

Slide 31 - Quizvraag

What means the number 2,419?

Slide 32 - Open vraag

Slide 33 - Open vraag

Slide 34 - Tekstslide

Antagonistic pleiotropy
Mutation accumulation
Selection shadow
Disposable soma 
Oxidative stress
in the case where harmful mutations are only expressed later in life, when reproduction has ceased and future survival is increasingly unlikely, then these mutations are likely to be unknowingly passed on to future generations.
concept involved with the evolutionary theories of aging that states that selection pressures on an individual decrease as an individual ages and passes sexual maturity, resulting in a "shadow" of time where selective fitness is not considered.
when one gene controls for more than one trait, where at least one of these traits is beneficial to the organism's fitness early on in life and at least one is detrimental to the organism's fitness later on due to a decline in the force of natural selection.
The reflextion of an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage.
Special case of antagonistic pleiotrophy: theorie that states that organisms age due to an evolutionary trade-off between growth, reproduction, and DNA repair maintenance.

Slide 35 - Sleepvraag

antoganistic pleiotrophy
Mutation accumulation
Disposable soma 
(AP; early
and late life effects of genes)
(MA; agespecific
expression of genes)
(maintenance vs

Slide 36 - Sleepvraag

Genetic factors (intrinsic)
Environmental factors (extrinsic)
GxE interactions

Slide 37 - Tekstslide

There are links found in the genotype that correlates with a longevity phenotype; genes that increase risk of dementia, cardiovascular disease and lung cancer.

IGF2R and POM121C are linked to the insulin pathway - do they increase or decrease the lifespan?

Slide 38 - Quizvraag

Why is there a difference in the reactions of c. elegans?

Slide 39 - Open vraag

Slide 40 - Sleepvraag

Waarom is de trend zo gestegen?
Door genetische aanpassing
Door ons eten

Slide 41 - Quizvraag

Slide 42 - Tekstslide


Slide 43 - Tekstslide

Absence of ageing?

Which graph would illustrate the intensity of selection ( ----) of the ming clam? Where there is selection on the soma (not on the germ-line).

Slide 44 - Quizvraag

Does ageing happen in organisms that have a distinction between germ line and soma?

(Such as prokaryotes, protozoa, algae)

Slide 45 - Quizvraag

Slide 46 - Tekstslide

Theorie assumes a trade-off between genes that have a positive effect early in life and a negative effect late in life. For instance those that influence reproduction: a higher reproduction often leads to a reduced lifespan.
Deleterious mutations can accumulate in those genes. Hence they will function not optimal and this will result in ageing or death. So selection acts on reproduction, not ageing. 
The DS assumes a trade-off between maintenance and reproduction. It states that maintenance should only be done when it is effective, ie that it affects a large enough part of the population. This concerned for instance those animals in which a large part of the population die at young age due to external factors, it is then not really effective to invest in very good maintenance.

Slide 47 - Sleepvraag