Bio quiz on sexual selection

 

  1. Male bower birds (birds that look like crows and live in Australia and Papua New Guinea) make elaborate structures (called bowers) out of grass and twigs. Males decorate their bowers with objects they find, like feathers of other birds, pieces of glass, shells, and bits of plastic: items that have no direct benefit to females. Females find some bower decorations VERY sexy and will mate with a male based on his bower decorations.

A. Propose a hypotheses for why this behavior in males and females evolved.

In pipefish (fish related to seahorses) instead of the female carrying the growing offspring, the male holds them in a brood pouch in his body until they hatch out. Basically, male pipefish are pregnant and their bodies supply the growing embryos with some nutrients required for development.

  • Large females that mate with males create more costly broods for males. In other words, it takes more energy for males to sustain their pregnancy with these offspring, mostly because many embryos inherited large size from their mother. Generally, the offspring of large mothers survive better than the offspring of small mothers.
  • Males can’t sustain multiple pregnancies in a short period of time from large females without substantial risks to their own health and survival.
  • After mating with a small female, male pipefish can “increase the rates of offspring abortion in pregnancies…to retain resources for future reproductive opportunities” (Paczolt & Jones, Nature, 2010).

A. Is the phenomenon of male-induced abortions Intersexual Selection or Intrasexual selection?

B. How would you describe it using the Sexual Selection categories that we discussed in class? (Hint: it is possible that we didn’t discuss this phenomenon from the male’s point of view.)

C. Briefly describe why you think such a phenomenon would evolve: specifically, why would males abort a brood of offspring mothered by a small female?

  1. In black goby fish, males build nesting sites (a “cave” made out of rocks and shells) in which the females lay their eggs. Males fertilize these eggs then care for them until hatching. Males attract females to their nesting sites by releasing pheromones (chemicals that influence the behavior of other goby fish) into the water. These pheromones also provoke aggression in other males.
  • In addition to “parental males”- those that create nesting sites and care for young, there are smaller males that do not make nesting sites but swim into the nests of other males (usually undetected) while a female is there laying eggs. These smaller males then release sperm in order to fertilize that female’s eggs.
  • Parental males have a large gland that produces lots of their “sexy” pheromone, while the smaller non-parental males have only a tiny pheromone gland.
  • In experiments, parental males exposed to the glandular extracts of other males (which would contain the pheromone) reacted with aggressive behaviors like tail-beating and biting toward the source of the pheromone. When parental males were exposed to the glandular extracts of small, non-parental males, they had no reaction (Locatello et al., Journal of Experimental Biology, 2010).

A. Is the phenomenon of non-parental males in this mating system an example of Intersexual Selection (between two different sexes) or Intrasexual selection (within the same sex)?

B. How would you describe it using the Sexual Selection categories that we discussed in class?

C. Briefly describe why you think such non-parental males would evolve to have no sexual pheromones.







Place your order
(550 words)

Approximate price: $22

Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
$26
The price is based on these factors:
Academic level
Number of pages
Urgency
Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our guarantees

Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.

Money-back guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read more

Zero-plagiarism guarantee

Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

Read more

Free-revision policy

Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

Read more

Privacy policy

Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

Read more

Fair-cooperation guarantee

By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Read more

Get 15% OFF on your FIRST order. Use the coupon code: new15