sexual selection (6-2) Flashcards
Hibernation is a phenomenon where animals such as bears, groundhogs, and bats slow down their metabolism and become inactive during the winter months. What are some plausible proximate and ultimate causes of hibernation, and how do they contribute to the survival of these animals?
The proximate cause of hibernation is a decrease in metabolic rate, body temperature, and heart rate. The ultimate cause of hibernation is to conserve energy during times when food is scarce and environmental conditions are harsh. By reducing their metabolic rate and activity, animals are able to save energy and survive long periods without food. Additionally, hibernation also helps animals avoid predation, conserve water, and maintain their body temperature during the winter months. Overall, hibernation is an adaptive strategy that allows animals to survive in challenging environments and increase their chances of reproduction and survival.
proximate vs ultimate explanations
p= which mechanism triggers the behaviour (the how) eg. neural and developmental constarints
u= what purpose does particular behaviour serve (the why) historical and function constraint approach
peppered moth example; nefore industrial revolution the dominant phenotype was white pepperd moths. after industrial revolution black peppered took over and became majority. (think of how there was much more soot at this time) proximate and ultimate
proximate= the genes present encode for a dark phenotype
ultimate=black moths were better able to blend in with environment therefore after many generations they had increased reproductive success.
Male elephant seals engage in violent battles during the breeding season. What are some plausible proximate and ultimate causes of this behavior, and how does it contribute to the survival and reproductive success of the species?
proximate cause of male elephant seals engaging in violent battles during the breeding season is the need to establish dominance and access to females. Male elephant seals engage in fights by slamming their bodies into each other and using their sharp teeth to inflict wounds. The ultimate cause of this behavior is to maximize their chances of reproductive success by acquiring a harem of females. The more dominant males are more likely to mate with multiple females, passing on their genes to the next generation.
“experiments and observations focused on understnding how specific gene products, neuron activity, and hormonal signals cause behaviour.”
proximate or ultimate.
proximate
when new lions take over a pride, they kill all cubs from previous lions. which is the proximate reason.
a) females are forced to have cubs fathered by new males
b) males do not recognize/ hate cubs they didnt know as newborns
b
what does behaviour result from?
a) solely dtermined by genes
c) affected by enviornemnt only
c) both- correct!!
bc behaviour can be thought of as phenotype as phenotypes are the observable result of a genotype and the enviornment
sexual selection
form of natural selection that favours individuals with traits that increase their ability to obtain mates or choose good mates
batemans principle
the idea that the number of offspring depends on how many mates a male can sttract. but this doesnt apply to females. this is bc males can produce energetically cheap and many gametes so they can fertilize eggs at a much faster rate than females can produce and get fertilized
This principle is the theory that females almost always invest more energy into producing
offspring than males, and therefore, in most species, females are a limiting resource over which the
other sex will compete.
intersexual selection vs intrasexual selection
inter= females choose males that present themselves with quality traits eg. peacocks, widowbirds (ornaments)
intra=males compete with eachother and determine who mates with female. eg. moose, elephant seals (armaments like antlers or big noses to fight)
male zebra finch example
they have colourful cheek feathers. the pigment helps support immune system and so the more colourful indicates the healthier the bird. females go for more colourful males. intersexual selection favours evolution of male ornaments so they can signal their quality to females
handicap principle
indicates that if a male can survive with handicaps such as long tails in widowbirds (that make flying difficult and easier target for predators) implies that the males a good mate therefore signaling quality
these are costly morphological or behavioural handicaps
Suppose you were studying several species of monkeys.
In one species (A), males never helped females raise offspring.
In another species (B), males provided just as much parental care as females after
the birth of the offspring.
species b will have low dimorphism and A will hve high dimorphism
