Concept explainers
To review:
Comparison of fundamental asymmetry of sex and sexual dimorphism between the two-monkey species.
Introduction:
According to the Bateman–Trivers hypothesis, two processes are involved namely pattern and process. In this, the pattern refers to the trait, which attracts the members of the opposite sex and it is highly expanded in the males. In the process, high energy expense is required for the formation of large egg, whereas the sperms contain few energetic
During study of several species of monkeys in one case, males never helped females to raise offspring. While in another case, males provided just as much parental care as females except for actually carrying the fetus during pregnancy.
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Chapter 23 Solutions
Biological Science (7th Edition)
- My college Bio teacher asked me this question in response to one of my photos I posted on Facebook: "I wonder why some birds exhibit sexual dimorphism while others do not." Can someone explain this phenomenom in detail?arrow_forwardIn many hummingbird species in North America, males but not females have a bright red throat patch and both sexes show a preference for red-colored flowers over those with different colors. How would you determine that the sexual dimorphism in throat patch coloration in male hummingbirds evolved by sensory exploitation?arrow_forwardIn seahorses, males incubate and care for offspring. Thus, the males are more likely to be tied up in reproduction at any point in time relative to females. Which sex do you predict will be the choosey sex in this species and why? Males -- because fewer are available to mate Males – because male-male competition is incredibly strong Females – because sperm are cheap to produce Female – because the operational sex ratio is biased in their favorarrow_forward
- Uniquely explain the relationship between primate mating groups and sexual dimorphism in your own words.arrow_forwardWhy does sexual dimorphism have important implications for studying human evolution? Explain why and prove it with examples.arrow_forwardBecause the reproductive success of female Hanuman langurs (Semnopithecus entellus) is almost certainly lowered when a newly installed male kills their young infants, selection should favor countermeasures against infanticidal males. In this light, why might already pregnant females mate with a new male soon after a takeover even though they are not ovulating? What significance do you attach to the discovery that when mares are impregnated by stallions at stables away from their home locations, they will also copulate repeatedly with the males in their home stables upon their return?arrow_forward
- Mate guarding is an evolved response to sperm competition. Chimpanzee (Pan troglodytes) females regularly mate with several males in the same estrous cycle, whereas gorilla (Gorilla gorilla) females almost never do, since they typically live in bands, each controlled by a single, powerful male. How large (as a proportion of body size) should the testes of chimpanzee males be relative to gorilla testes (Harcourt et al. 1981)? If the testes of men are more similar to those of chimpanzees, what would this tell us about the intensity of sperm competition during our evolutionary past? If, on the other hand, human testes resemble those of gorillas, what conclusion is justified? Please don't write from any online source.arrow_forwardWhat are the relative advantages and disadvantages ofsemelparity and iteroparity? In answering, consider iteroparousspecies that have both short and long expected life spans in theirnatural environments.arrow_forwardWhat is evidence that menopause is an adaptive cooperative trait? In humans, the presence of reproductive (fertile) grandmothers probably increases the survival rate of their grandoffspring. O In killer whales, the presence of reproductive (fertile) grandmothers increases the survival rate of their grandoffspring. In both humans and killer whales, the presence of non-reproductive grandmothers probably increases the survival rate of their grandoffspring. In humans, the presence of reproductive (fertile) mothers increases the survival rate of their reproductive grandparents.arrow_forward
- The change of successful fertilization is approximately 18% in every cycle. Why does this statistic seem so low? All of the following statements provide a reason as to why the chance of fertilization is 18% every ovarian cycle EXEPT Select one: A. Some Sperm cells are not very motile, while others are formed without a tail. B. If more than one sperm fertilizes an egg, multiple embryos can result. C. Vagina is very acidic, killing many sperm. D. There two fallopian tubes and two ovaries, but only one of them releases an ovum every cycle.arrow_forwardIn the early 2000s, scientists have determined that the nation's top-selling weed killer, atrazine, disrupts the sexual development of frogs at concentrations 30 times lower than levels allowed by the Environmental Protection Agency (EPA), raising concerns about heavy use of the herbicide on corn, soybeans and other crops in the Midwest and around the world. The amphibians (the frogs) are exposed to atrazine when in water. [atrazine frog Given that log Kow for atrazine is 2.65 and that log 0.85 log Kow - 0.07. %3D [atrazine]pater If the atrazine concentration in the water is 100 ng/L, what would be the concentration of atrazine in frogs in ppm?arrow_forwardMale parental care occurs in only 7% of fishes and amphibianspecies with internal fertilization but in 69% of species with externalfertilization. Propose an explanation for why this is so.arrow_forward
- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning
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