37 Questions
What are life history traits?
Life history traits include an organism’s age at first reproduction, the duration and schedule of reproduction, the number and size of offspring produced, and life span.
How do life history traits vary among different species?
Short life, many eggs; Reproduce once in a short life; Long life, fewer offspring; Continually reproduce over a long life.
What do life history traits involve?
Life history traits involve trade-offs, as there is a limited amount of energy to invest in survival, maintenance, and reproduction.
What does natural selection aim to maximize in life history?
Natural selection aims to maximize the number of offspring surviving to maturity.
How does the presence of predators influence life history traits?
Data from opossums on Sapelo Island, GA, show that with no predators, island opossums live longer and have fewer offspring.
What is a potential trade-off for living longer?
A potential trade-off for living longer could be having fewer offspring.
How do life history strategies change over time?
Life history strategies are subject to evolution, as they are influenced by environmental factors and reproductive success.
What are some examples of life history traits?
Examples of life history traits include an organism’s age at first reproduction, number of offspring produced, and life span.
How do offspring sex ratios of organisms like wasps (Hymenoptera) contribute to maximizing fitness?
Organisms may regulate the sex ratio of offspring to maximize fitness.
According to the Trivers-Willard hypothesis, in what condition do mothers produce females?
Mothers produce females when in poor condition.
When in good condition, what sex do mothers produce according to the Trivers-Willard hypothesis?
Mothers produce males when in good condition.
Why do some organisms cannibalize eggs or offspring?
Organisms may cannibalize eggs or offspring for higher fitness and survival of the remaining offspring.
How can females of certain species like sand gobies alter the sex ratios of their offspring?
Females may alter sex ratios of offspring to ultimately enhance fitness and survival in the offspring.
What is the mechanism behind females altering the sex ratios of their offspring in species like fig wasps?
Females of fig wasps and other Hymenoptera can alter sex ratios through haplodiploidy.
How do females adjust the sex ratios of their offspring in species like thrips?
Thrips, like fig wasps, are haplodiploid and females can adjust sex ratios using this genetic system.
What is the main benefit for organisms in regulating the number of offspring they produce?
Organisms regulate the number of offspring to maximize fitness over their lifetime.
What type of selection is described in the text?
Frequency-dependent selection
Explain the advantage of being the rare sex in terms of mating opportunities.
The rare sex has more mating opportunities.
What is genomic imprinting?
Gene expression silenced by methylation by one parent.
What is the difference between mules and hinnies?
Both hybrids of horses and donkeys, but different species is the father.
Define epigenetics.
Heritable changes in gene expression, perhaps accrued during the individual’s lifetime due to behavior and environment.
What is the role of predation risk in driving life history evolution in guppies?
High predation leads to guppies having more offspring, lower weight, and younger reproductive age.
What is the trade-off observed in guppies in predator-free streams for 11 years?
There is a trade-off between reproduction and growth/survival visible during the lifetime of an individual.
How do anolis lizards demonstrate parental investment?
Females are more likely than males to provide parental care.
In which species is there a sex role reversal where males provide parental care and females guard harems of males?
Jacanas.
What is the Operational Sex Ratio (OSR)?
OSR is the ratio between sexually receptive males and females in a population.
Do you predict OSR to be male or female-biased in jacanas?
Female-biased.
What is the importance of mate choice in male pipefishes?
Mate choice is important for male pipefishes.
What variation is observed in the number of mates between male and female pipefishes?
Male pipefishes vary in the number of mates compared to females.
What is a possible mechanism that is responsible for the difference in sex ratio adjustment between birds and mammals?
Some species switch sex in a “Trivers-Willard-predicted” manner
Why do we predict that some species will switch sex in a 'Trivers-Willard-predicted' manner?
Cost-benefit analysis
What is the sex ratio adjustment mechanism observed in Bluestreak cleaner wrasse?
Start as females and switch to males when large
In which species are sex ratios controlled by Wolbachia bacteria?
Some species of booklice
What is the sex ratio adjustment mechanism where some females only have daughters and transmit genes from their mothers?
Pseudo-arrhenotoky
What is paternal genome elimination?
Males inherit but do not pass on their father’s genetic material
Why are sex ratios often balanced?
To maximize reproductive success and genetic diversity
What is one potential benefit of having daughters in species where females adjust the sex ratio based on resource availability?
Daughters can help raise more offspring
Explore concepts such as evolution of life history traits, parental investment, sex ratios, conflict in life history traits, and life history strategies in BIO 4083 lecture. Learn about patterns of investment in growth and reproduction, age at first reproduction, offspring production, and life span.
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