Exam 2 PPTs Flashcards
Tungara frogs
- Female tungaras placed between loudspeakers playing different calls tend to approach the speaker emitting the more …. song
- precisely the same preference is shown by …
complex;
frog-eating bats
The theory of evolution by natural selection can readily explain some cases of …
sexual dimorphism
The theory of evolution by natural selection can readily explain some cases of sexual dimorphism:
purple-throated carib:
- males - which are larger and … - tend to ….
- females are, instead, more strongly associated with the flowers of H. bihai
socially dominant;
monopolize the favored food (H. caribaea)
The theory of evolution by natural selection can readily explain some cases of sexual dimorphism:
weevil:
- divergent traits may also be adaptive for … reasons, as when males and females play different roles in …
- the females of this beetle use their elongated snouts to bore holes deep into the buds of their …, into which they …
intrinsic;
reproduction;
host plant;
deposit their eggs
A great many other cases of sexual dimorphism present considerably more challenging puzzles:
- if a fan of iridescent eyespots improves the survival or fecundity of a peafowl, why do the hens not have them? How could a fan of iridescent eyespots improve survival or fecundity in the first place?
- As with complex songs of tungara frogs, male peacocks are easier for …
- elaborate plumage requires considerable …. to grow, maintain, and drag around.
predators to find and catch;
energy
A great many other cases of sexual dimorphism present considerably more challenging puzzles:
- elaborate plumage requires considerable energy to grow, maintain, and drag around. energy spent on feathers is energy that …
cannot be spent on making offspring
Sexual reproduction has two big challenges:
- …
- then …
surviving to adulthood;
reproducing
Sexual reproduction has two big challenges:
- surviving to adulthood
- then reproducing: finding a member of the opposite sex and …
Darwin realized that individuals vary not only in their success at …. and … but also in their success at …
persuading him/her to mate;
surviving; reproducing;
persuading members of the opposite sex to mat
…, just like dying young, can severely curtail an individual’s genetic contribution to future generation
failure to obtain a mate
Sexual selection:
- differential reproductive success due to variation among individuals in …
- we can develop a theory of evolution by sexual selection that is logically equivalent to the theory of evolution by natural selection: if there is heritable variation in a trait that affects the ability to …, then variants more conducive to … will become more common over time
their success at getting mates;
obtain mates;
success
Asymmetries in Sexual Reproduction:
Orangutan:
- Adults of opposite sex tolerate each other’s company for one purpose only, …
- if a pregnancy results, then the mother, who weighs about 40 kg, will carry the fetus for 8 months, give birth to a 1 kg baby, nurse it for about …, and continue to protect it until it reaches the age of …/…
- for the father, who weighs about 70 kg, the beginning and end of parental investment is … - which he can replace in a matter of hours/days
- how can this affect males/females differently?
reproduction;
3 years;
7;8;
a few grams of semen
Asymmetries in Sexual Reproduction:
Orangutan:
- orangutan mothers invest considerably more … and … in each offspring than orangutan fathers do
- in more than 90% of mammal species, … provide substantial parental care and the opposite sex provides little to none
time;
energy;
females
Asymmetries in Sexual Reproduction:
- in most animal species, …
- eggs are typically large and yolky, with a big supply of … and …
neither parent cares for the young;
stored energy;
nutrients
Asymmetries in Sexual Reproduction:
- in many animals, … (or …) are more expensive than …
- mothers typically make a … constructing and caring for the offspring than fathers do
animals;
pregnancies;
ejaculates;
larger parental investment
Asymmetries in Sexual Reproduction:
- parental investment increases the … of the offspring receiving it. At the same time, it decreases the remaining … that the parent may achieve in the future by way of …
reproductive success;
reproductive success;
additional offspring
Asymmetries in Sexual Reproduction:
- female: reproductive success of females is usually limited more by the … or … than by the number of …she can …
number of eggs she can make;
pregnancies she can carry;
males; convince to mate with her
Asymmetries in Sexual Reproduction:
- male: reproductive success usually limited more by the number of …. than by the number of …
females he can convince to mate with him;
ejaculates he can make
Asymmetries in Sexual Reproduction:
- female reproductive success limited more by eggs/pregnancies
- male reproductive success limited more by number of mates
- under such circumstances differential reproductive success due to variation in mating success will be a more potent mechanism in the evolution of … than in the evolution of …
Mating Success and Reproductive Succes in a Newt:
- in rough-skinned newts, for males, more mates meant …
males;
females;
more offspring
Mating Success and Reproductive Success in a Pipefish:
- for females, more mates meant …
more offspring
Behavioral Consequences of Asymmetrical Limits on Fitness:
When sexual selection is strong for one sex and weak for the other, we can predict that:
- members of the sex subject to strong sexual selection will be …
- members of the sex subject to weak sexual selection will be …
competitive;
choosy
Sexual Selection on Males:
- sexual selection by male-male competition often occurs when individual males can monopolize …
- male-male combat over access to mates can favor … traits including …, …, …
access to females; morphological traits; large body size; weaponry; armor
male-male competition on marine iguanas: combat:
- … natural selection on size: medium-sized iguanas survive at higher rates than either small or large iguanas
- larger iguanas can harvest more … and thus gather more …, but they also expend more energy on …
stabilizing;
algae;
energy;
metabolism
male-male competition on marine iguanas: combat:
- stabilizing natural selection on size
- larger iguanas can harvest more algae and thus gather more energy, but they also expend more energy on metabolism
- small iguanas ran a …
- large iguanas ran a …
net energy surplus;
net energy deficit
male-male competition on marine iguanas:
sexual selection on male size: larger males have …
- male iguanas … on the rocks where females bask between feeding bouts
- … males tend to win
more mates;
fight for territories;
bigger
male-male competition on marine iguanas:
- sexual selection on male size: larger males have more mates
- because only some males manage to claim territories, because some owners maintain their claims longer than others, and because females prefer some territories and owners over others, there is … among males in …
extreme variation;
copulatory mating success
male-male competition on marine iguanas:
- sexual selection on male size: larger males have more mates. explains why male marine iguanas get so much bigger than the …
optimal size for survival
male-male combat can also lead to the evolution of alternative mating strategies:
- small adult males are … from the mating territories on the basking grounds. however, they do get about …% of the matings in the colony
- copulations by small males are more likely to be … (by large males) before the male has time to ejaculate - which typically happens after about 3 mins
ousted;
5;
disrupted
male-male combat can also lead to the evolution of alternative mating strategies:
- copulations by small males are more likely to be disrupted by large males before the male has time to ejaculate
- the small males solve this problem by … They use the stimulation of an attempted copulation, or even of seeing a female pass by, to …
- the males then store the ejaculate in their … if he gets a chance to mate, a small male … to the female at the beginning of copulation
ejaculating ahead of time;
induce ejaculation;
cloacal pouches;
transfers his stored ejaculate
sexual selection on males: sperm competition:
- sperm competition: the real determinant of a male’s mating success is not whether he copulates, but whether ….
- if an animal has internal fertilization, and if a female mates with two or more different males within a short period, then the sperm from the males will be in a …
his sperm fertilize eggs;
race to the eggs
sexual selection on males: sperm competition:
- batches of offspring with … have been documented in a variety of animals, including squirrels, bears, birds, lizards, and spiders
- it happens in humans too: several reports of twins with …
multiple fathers;
different fathers
sexual selection on males: sperm competition:
- the real determinant of a male’s mating success is not whether he copulates, but whether his sperm fertilize eggs
- males may produce large …
- males may … their mates
- …
- deposit a …
- apply … that reduce the female’s …
ejaculates; guard; prolong copulation; copulatory plug; pheromones; attractiveness
sexual selection on males: infanticide:
- infanticide: in lions, newcomer males kill unweaned cubs so that the females return to … earlier
- infanticide by males is the cause of about …% of all cub deaths in the first year of life and over …% of all lion mortality
breeding condition;
25;
10
sexual selection on males: female choice:
- in general, males … if they are unable to monopolize females or any …
- female typically …. advertisements of … before they choose a mate
- sexual selection by mate choice leads to the evolution of ….
advertise for mates; resource vital to females; inspect advertisements; several males; elaborate courtship displays
sexual selection on males: female choice:
- evolutionary biologists have devised numerous hypotheses about how and why female preferences evolve:
1. choosy females may benefit directly through the …
2. choosy females may get better …
acquisition of resources;
genes for their offspring
sexual selection on males: female choice:
choosy females may get better genes for their offspring
- selection acts on female indirectly via the production of …
- if males with attractive displays are … to males giving less attractive displays, then choosy females will secure … for their offspring
high-fitness offspring;
genetically superior;
better genes
sexual selection on females:
- …: multiple mating by females
gunnison’s prairie dogs
- the probability of getting pregnant and giving birth was 92% for females that had only …, but 100% for females that had …
polyandry;
one or two mates;
three or more
