EXAM 3 3/25 Flashcards
what does imprinting mean as an adult
Males and females exhibit behaviors that are influenced by early life experiences, such as imprinting on their mothers.
The initial imprinting often leads them to follow figures or patterns they first encountered in their early days.
what qualities make a male desirable to a female
Male animals often use physical traits like vibrant colors or feathers to attract mates.
The female’s choice of mate is based on perceived health, strength, or genetic traits.
Females assess potential mates by their displays and other attributes like nest-making skills or food provision.
mating displays
Male birds use physical displays and gather objects to impress females, often risking exposure to predators.
The male’s display can include collecting shells, bright objects, or other material to show off.
how do animals with mating displays avoid attracting predators
Some animals adapt by hiding or limiting their displays during breeding seasons to avoid attracting predators.
The balance between attracting mates and avoiding predators is a critical survival tactic.
what traits increase the cases of winning and intrasexual competition
Physical size aggression and dominance
intersexual selection mate choice
The quality of the male’s territory.
The resources available in that territory.
Other characteristics that signal genetic fitness.
do females always have a choice in her mate
Not always sometimes if a male chased another male away, she will just mate with the one thats left females are often passive and let males control this situation
what is the biological theory behind why females invest more than males
Egg size (larger) and sperm size (smaller), reinforcing the idea of unequal investment.
Females have fewer eggs (a few hundred), whereas males produce billions of sperm.
Egg value is higher to females than sperm is to males.
What happens to female investment in species where eggs compete internally?
greater female investment in mammals, fish, and some insects
do females show more investment in all species
No, we see this in male sticklebacks, seahorses, and frogs. In species where women are polyandrous the male has higher investment
Who courts whom in locusts?
Courtship ritual involves males producing chromatophores (nutrient-rich balls with sperm embedded).
The female absorbs the nutrients from the chromatophore to develop eggs.
Smaller chromatophores: The male courts the female.
Larger chromatophores: the female courts the male (it shows he spent more time and investment into mating)
sexual selection vs natural selection
Sexual Selection: Traits that increase mating success, like the peacock’s tail. (larger is favored.)
Natural Selection: Traits that increase survival (e.g., avoiding predators). A large tail in peacocks would not be favored under natural selection because its vulnerable to predators
The balance between sexual and natural selection often determines the evolution of exaggerated traits, like the peacock’s tail.
runaway sexual selection
Evolutionary process where a trait becomes exaggerated due to female preference, even if the trait has no survival advantage.
ex: Male peacocks’ tails became larger because females preferred them, even though large tails may hinder survival. it is costly in terms of energy and predator risk
ex: stalk eyed flies
Male stalk-eyed flies develop long eye stalks, with some extending past the length of the animal’s body. The original benefit was better 3D vision, but the trait became exaggerated as females began selecting for larger stalks, even though the benefits of longer stalks beyond a point were minimal.
what trait is beneficial in both sexual selection AND natural selection
Physical fitness can increase both survival and attractiveness to the opposite sex.
Healthy males are more likely to survive and are thus preferred by females, who tend to select mates based on physical condition.
Are females always more selective?
No, the sex investing more in offspring tends to be choosier.
resource provisioning
Males may provide resources such as territory, food, or gifts to attract females.
Example: In some species, males may provide food as a gift that is important for the female’s reproductive success.
Human Example: In some human cultures, there’s a concept called the “bride price,” where the groom’s family gives gifts or resources to the bride’s family, which can be seen as a form of direct benefit.
good genes hypothesis
Females select males with traits signaling good genes, which will be passed onto offspring, increasing their survival and reproductive success. These traits include good health and symmetry, which signal the absence of genetic anomalies or disease.
what kind of symmetry is associated with better health
bilateral symmetry
secondary sexual characteristics
Traits that are not directly related to survival but attract mates.
Examples include the vibrant plumage of birds or the volume of a bird’s song.
sexy son hypothesis
Females prefer mates whose traits will produce attractive sons, thus increasing the chance of their offspring’s reproductive success.
How can female house finches become colorful?
when they are fed the male diet. This indicates a genetic predisposition for color expression. the males diet makes them more colorful and more attractive to females.
extra pair matings
Females may “cheat” by mating with more attractive males outside their primary partner, typically males with more pronounced secondary sexual characteristics. This can lead to more successful offspring, indicating attractive traits are often linked to better reproductive success
monogamy
Males may stay with a single female, investing more time and resources in raising offspring.
polygamous species
Males seeking multiple mates to increase their reproductive success, leading to more variation in offspring characteristics.
do most species have intrasexual selection or intersexual selection
Most species have both intersexual selection and intrasexual selection
