Life History Evolution - 3 | Growth & Maturation

Lecture Marc Naguib
Growth and sexual maturity
Growth & Sexual maturity
- Age and size at maturity
- Sex differences in age and size at maturity
- Age at maturity in humans
Fitness effects in fish
- Growth curves and reaction norms
- Growth and sexual maturity in guppies
- Effects of the social context in guinea pigs
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Slide 1: Tekstslide
BiologieMiddelbare schoolvmbo bLeerjaar 3

In deze les zitten 35 slides, met interactieve quizzen, tekstslides en 1 video.

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Lecture Marc Naguib
Growth and sexual maturity
Growth & Sexual maturity
- Age and size at maturity
- Sex differences in age and size at maturity
- Age at maturity in humans
Fitness effects in fish
- Growth curves and reaction norms
- Growth and sexual maturity in guppies
- Effects of the social context in guinea pigs

Slide 1 - Tekstslide

Grows slowly
Reaches 60 cm
Matures at 14 years
Lives 30 years
Grows fast
Reaches 25 cm
Mature at 3 years
Lives 6 years

Slide 2 - Sleepvraag

What makes fish good examples for age and size of maturity?

Slide 3 - Open vraag


What components for the differences could researchers investigate? 

Slide 4 - Open vraag

In
A

Slide 5 - Quizvraag

In what region do you expect which factor? 
Newfoundland
Scotland
Warmer water
no feeding in winter (stress)
maturation during winter is costly
cold water
increase in investment will cause more stress and lower white muscle fibre weight, which leads to lower predator avoidance
pays to grow to size where predation is low and to mature at that size
no winter fasting
less predation pressure so maturing earlier pays off

Slide 6 - Sleepvraag

What are benefits of later maturation?

Slide 7 - Open vraag

What are costs of late maturation?

Slide 8 - Open vraag

What are benefits of early maturation?

Slide 9 - Open vraag

What are costs of early maturation?

Slide 10 - Open vraag


1. What is similar for fish and mammals?
2. What is different? 
3. How could the differences be explained?

Slide 11 - Open vraag


1. When can it be beneficial to start as a female?

2. When can it be beneficial to start as a male? 

Slide 12 - Open vraag

If there's an optimum situation for time of maturation and reproduction, why does not everyone follow it? (Why are individuals not born with a fixed decision rule?)

Slide 13 - Open vraag

Slide 14 - Tekstslide

Why are guppies a very usefull species for research?

What answer is least correct?
A
Strong variation in life history traits among populations, short generation time (as do birds)
B
Fecundity is size dependent
C
More similar physiology to humans than other species
D
Experimental possibilities in field and lab

Slide 15 - Quizvraag

females produce fewer offspring
females produce bigger offspring
females produce many offspring
females produce smaller offspring

Slide 16 - Sleepvraag

Slide 17 - Video

Intro | Become large with compensatory growth or stay small....
When there are poor nutritional conditions, it pays off to remain small, but larger individuals have higher fecundity. What are the trade-offs?


Blue line: you're in good conditions, you mature early / red line: you're not in good conditions and you age differently

Slide 18 - Sleepvraag

What is a heterogeneous environment?
A
An unpredictable and diverse environment (div nesting situations / nutrional / predator wise)
B
Environment that is predictable an not diverse

Slide 19 - Quizvraag

What is the conclusion drawn from the graph?

Slide 20 - Open vraag

What is a life-history trait?

Slide 21 - Open vraag

What is a life-history trade-off?

Slide 22 - Open vraag

How can intrinsic AND extrinsic factors influence phenotypic plasticity

Slide 23 - Open vraag

Why does demography depend on life history events?

Slide 24 - Open vraag

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

Slide 25 - Open vraag

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.

Slide 26 - Tekstslide

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). 

Slide 27 - Tekstslide

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

Slide 28 - Open vraag

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.

Slide 29 - Open vraag

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

Slide 30 - Open vraag

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

Slide 31 - Open vraag

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

Slide 32 - Open vraag

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.

Slide 33 - Open vraag

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

Slide 34 - Open vraag

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.

Slide 35 - Open vraag