Life History Evolution - 11 | Mock Exam

• Biologie
• Middelbare school
• vmbo b
• Leerjaar 3

What is a life-history trait?

What is a life-history trade-off?

How can intrinsic AND extrinsic factors influence phenotypic plasticity

Why does demography depend on life history events?

Why does the evolution of life history traits depend on the demography of a population?

A. Give a definition and an implication of the “Predictive Adaptive Response” (PAR) hypothesis. B. Give two conditions required for the evolution of a predictive adaptive response.

ANWERS: See Dr. Piter Bijma’s lectures. The PAR hypothesis is also explained in the second paragraph of the introduction of the paper by Rickard and Lummaa(2007). Two conditions for the evolution of PAR are i) the environment that the mother experiences must be predictive of the offspring environment, ii) the environmental fluctuation that elicits the hypothesized PAR must be of sufficient frequency to maintain the selective advantage of plasticity. (These are just two answers, there are more in the paper: Rickard, I. J., & Lummaa, V. (2007). The predictive adaptive response and metabolic syndrome: challenges for the hypothesis. Trends in Endocrinology & Metabolism, 18(3), 94-99.

Discuss the trade-off between parental care and alticiality/precociality.

ANSWER: Altricial species require a higher investment in parental care than precocial species. Precocial species prioritize investment in prenatal development (eg offspring size and relative independence at birth/hatching), altricial species prioritize postnatal investment in offspring (parental care). In mammals, altricial species generally have larger litters while precocial species have few or one offspring at a time (i.e., trade-off between offspring quantity and offspring size, limited by female uterus), while in birds precocial species tend to have larger clutches (i.e., trade-off between offspring quantity and demands of parental care). 

Here you see a so-called cohort life table, in which a cohort of individuals is followed over its lifetime. Calculate: i) the net reproductive rate; ii) the geometric growth rate

The early environmental conditions can affect various classic life history traits. Life history decisions, like reproductive decisions, include the choice of a partner. Female songbirds prefer specific male songs.

Describe an experiment, which controls for other males traits, on how you can test such a preference.

The early environmental conditions can affect various classic life history traits. Life history decisions, like reproductive decisions, include the choice of a partner. Female songbirds prefer specific male songs.

QUESTION: Song of male songbirds should honestly reflect information about the male but males learn their song. Name two arguments why early nutritional conditions are expected to affect song

What is the definition of the Lack’s principle(or Lack clutch)?

I. Are clutch sizes observed in the wild usually smaller, similar or larger than the Lack clutch size? Explain why

II. Provide two reasons for the phenomenon described in question I, one focused on the parents and one focused on the offspring. Provide arguments for your answers

This figure illustrates fertility and survival as a function of age in three different species.

a. What general trend do you see in fertility and annual probability of survival in all three species?

b. What biological process do these trends describe?

c. Why are these trends considered an evolutionary puzzle?

d. Name two theories that provide a solution for this puzzle.

Considering that selection pressures drop with age, how did ageing develop in the context of life history evolution?

Many human generations ago, most women worldwide began childbearing in their mid-teens. Today, a large proportion of women worldwide delays childbearing until their 20s. Among higher-educated women in developed nations, the trend in delaying reproduction has been taken even further; with childbearing often delayed until past 30 due to education and career pressures. Suppose that the majority of women worldwide were to delay childbearing until 30, and that women were to continue to make this choice for many human generations. Make a prediction about how human lifespan and fertility might evolve in response. Give a short evolutionary explanation for your predictions on these traits.