Sexual selection pt.2 Flashcards
What are the two main components of sexual selection?
Male:male competition and mate choice.
Name 2 species where females gain direct benefits from mate choice
-Gaining resources (e.g. nutrition)–> e.g. bush crickets, hangingfly
-Gaining good paternal care of young–> e.g. fifteen-spiked stickleback
What is the correlation between the duration of copulation in hangingfly and nuptial prey size?
The larger the nuptial prey size, the longer the duration of copulation, therefore the more likely sperm is to be transferred
What is the Bateman Principle?
It states that potential reproductive rate varies by sex, influencing parental care and reproductive strategies.
What is the difference between direct and indirect benefits of mate choice?
Direct benefits provide immediate advantages (e.g., resources), while indirect benefits enhance genetic quality or compatibility.
Name a direct benefit of mate choice for females
Gaining resources such as territory or food.
Give an example of a species where females gain good paternal care.
Fifteen-spined stickleback.
Name some direct benefits of sexual selection
-Territory
-Food
-Nutrients
-Protection
–> predators
–> other potential mates
–> Paternal (maternal)
What is a lek?
A communal area where males display to attract females, common in polygamous species.
What is the “lek paradox”?
The question of why mate choice evolves when matings provide no direct benefits.
What are attractive sons in the context of mate choice?
A concept where females choose attractive males, leading to offspring that inherit both attractive traits and the preference for such traits.
Name an element of sexual selection in bats
developing sounds for competition with other males
What is Fisher’s runaway hypothesis?
A theory explaining the coevolution of male ornament genes and female choice genes.
-the genes that allow choice
In terms of indirect benefits of mate choice (to females), what is a sign of “good genes” in a male?
What is an example of this?
-ornamental displays or display is extravagant or costly
-Peacock females mating based on size of male eyespots who produced offspring with faster growth rates and higher survival
What do quality of genes also include? What is this hypothesis called? Give an example
could include genetic resistance to parasites (Hamilton-Zuk hypothesis).
E.g.) Barn Swallow (males with longer tail streamers carry fewer parasites and their offspring have fewer parasites).
How do extravagant male displays signal quality?
They indicate the male’s fitness, ensuring honesty in signaling
In terms of indirect benefits to mate choice (to females), what are some examples of compatible genes?
-choose mate of correct species
-choose mates that are unrelated to avoid inbreeding e.g.) many mammals
Which organisms choose mates with compatible immunity genes?
Salmon
What shows that there is a cost to male’s extravagant displays?
E.g) males have elongated tales which are expensive to maintain and hamper manoeuvrability
What is the Hamilton-Zuk hypothesis?
It suggests that males with extravagant traits are more resistant to parasites, benefiting offspring
Give an example of a species that demonstrates the Hamilton-Zuk hypothesis
Barn Swallow, where males with longer tail streamers carry fewer parasites.
What are compatible genes in mate choice?
Genes that ensure successful reproduction, such as avoiding inbreeding or selecting for compatible immunity genes.
Why do females often choose mates that are unrelated?
To avoid inbreeding and increase genetic diversity.
What is the role of parental investment in sexual selection?
It influences the potential reproductive rate and shapes mating behaviors.
How do high potential reproductive rate (PRR) sexes typically behave?
They compete to maximize the number of mates.
What behavior is typical of low PRR sexes?
They are more selective in mate choice.
What behaviour is typical of low PRR sexes?
They are more selective in mate choice.
What is the significance of male displays in lekking species?
They attract females and can indicate male fitness.
What is meant by “good genes” in mate choice?
Males signal their genetic quality through costly traits, ensuring offspring inherit favorable genes.
What is the benefit of choosing mates with compatible immunity genes?
It enhances the offspring’s chances of survival and health.
How does sexual selection interact with natural selection?
Traits favored by sexual selection may also confer survival advantages.
What is the primary focus of sexual selection?
Traits that affect competition for mates and mate choice.
How does the size of gametes relate to parental investment?
Larger gametes typically correlate with higher parental investment and lower potential reproductive rates.
What is the impact of male:male competition on sexual selection?
It drives the evolution of traits that enhance male attractiveness and competitiveness.
Why might females benefit from choosing mates with extravagant displays?
Such displays may indicate genetic fitness and lead to healthier offspring.
What is a common misconception about mate choice benefits?
That all benefits are direct; many are indirect and enhance genetic quality.
How does mate choice influence evolutionary dynamics?
It can lead to coevolution of traits and preferences, shaping species over time.
What is the role of sexual selection in biodiversity?
It contributes to the diversity of traits and behaviours within species.
Summarise the main points of sexual selection.
It involves competition and choice, varies by sex, and offers both direct and indirect benefits influencing reproductive success.
