Life History Evolution - 4 | Reproduction and Ageing

• Biologie
• Middelbare school
• vmbo b
• Leerjaar 1

Life History Evolution | 4. Reproduction and Ageing - Bart Pannebakker

Variation in lifespan

Extrinsic mortality

Intrinsic mortality

GxE interactions

Immortality

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

Invertebrates

FISH

TETRAPODA

Why do bats live so much longer than other mammals of the same size?

1. Because they're dormant for a large period of the year and they don't age in that period.
2. Ability to fly is the key, it gives them a greater chance to survive.

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.)

1. Reproductive lifespan
2. Senescence
3. Lifespan
4. Mortality rate

Semelparity

Iteroparity

How do these species differ in their reproductive strategie? 

Semelparity vs Iteroparity

When is a single reproductive event in a lifetime favourable?

When is a single reproductive event in a lifetime favourable?

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.

What was the answer to Coles paradox?

1. Semelparity is always favourable
2. When parents have better extrinsic survival odds than juveniles, investing in intrinsic adult survival becomes worth it
3. Iteroparity is always favourable
4. If everyone is equally unsafe, then selection pressure is towards semelparity (e.g. stressfull conditions; high predation)

is the population size at time t

Longer reproductive lifespan | Mean mortality rates

Which one of the answers is correct?

1. When adult mortality is low, than is semelparity favoured
2. When juvenile mortality is low, than iteroparity is favoured
3. When neither of them are low, then iteroparity is favoured
4. When juvenile mortality is low, than semelparity is favoured

Bet-hedging:

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?

1. foraging behavior in bumble bees
2. 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.
3. female multiple mating
4. All are examples

What is the definition of ageing?

1. Late-life decline in individuals fertility and probability of survival
2. 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.
3. 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.
4. 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

Welk λ - getal hoort hierbij?

1. λ 1.0
2. λ -1.0
3. λ 0.5
4. λ 1.2

Why do organisms age?

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

What predictions could you make for these longevity of species with climate change?

1. The lifespan of organisms isn't effected
2. The lifespan of organisms shortens
3. Traits or characteristics that affect the life table of an organism, and can be imagined as various investments in growth, reproduction, and survivorship.
4. A tradeoff is where one thing increases, and another must decrease.

What is NOT correct about telomeres?

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

Oxidative stress theory of ageing

additional sources: e.g. NADPH oxidase, 5=lipoxygenase, xanthine, oxidase, peroxisomes, UV, heat -->

oxygen

< -- functional decline

mitochondria

Oxidative damage
lipids | proteine | nucleic acids

Ageing

ROS
(e.g. singlet oxygen, superoxide anion, hydrogen peroxide, hydroxyl radical

What theory applies for naked mole rats?

What means the number 2,419?

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.

antoganistic pleiotrophy

Mutation accumulation

Disposable soma 

(AP; early

and late life effects of genes)

(MA; agespecific

expression of genes)

(maintenance vs

reproduction)

GxE

Genetic factors (intrinsic)

Environmental factors (extrinsic)

GxE interactions

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?

1. Increase
2. Decrease

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

Waarom is de trend zo gestegen?

1. Door genetische aanpassing
2. Door ons eten

IMMORTALITY

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).

1. 
2. 
3. 
4. 

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

(Such as prokaryotes, protozoa, algae)

1. Yes
2. No

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.