BIOC54H3 Chapter 10: Chapter 10

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amaranthalpaca960

17 Oct 2011

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Chapter 10: bowerbirds: males build bowers that females visit, where she inspects then go, returns to the bowers later to be courted and then they copulate and builds a nest females raise young all by herself. 20 species of bowers, 17 build bowers: single common ancestor with trait that evolved once, possibility of building bower is that the original builder conveyed avenue bower and maypole bower information about his quality as a mate. Different bowers have different designs (neatness, decorations, etc) Sperm designed to race towards eggs: no gamete is good at both tasks. Time and energy to perform displays, but increases predation risk: sexual selection is a subcategory of natural section but the distinction is on the. Good fighters have more mates: some males fight for dominance hierarchy, collared lizard: faster lizards have largest territories and more offspring, savanna baboons: males compete for social status.

Related Questions

a) Why might selection have favored the preference female sage grouse have for the male sage grouse mating display? That is, what might males be signaling with this behavior, and why might it be in a femaleâs interest to choose a male based on his display?

b) What is the name of the mating system exhibited by great crested grebes, and what may have been one selective factor explaining why it evolved?

C) Propose a different hypothesis for why selection might have favored the preference female bowerbirds exhibit for blue coloration. (Isn't the reason why bowerbirds prefer the blue coloration is because it may be similar in color as to one of their resources attracting female bowerbirds to mate with them?)

- can someone also check if my answer to this question is correct (letter d).

d) Propose a hypothesis for why selection might have favored the preference females have for bower-building in male satin bowerbirds? That is, what might males be signaling with this behavior, and why might it be in a femaleâs interest to choose a male based on his display?

Bower building males signal females that their nest is the most suitable to lay their eggs and reproduce. It would be in the females best interest to choose a bowerbird with the best bower build because it is a preference that has been passed on in the species and by doing so its offspring will also choose intricate bower building mates.

lemoncheetah578

Suppose that females of one population of strawberry poison dart frogs (Dendrobates pumilio) prefer to mate with males that have a bright red and black coloration. In a different population, the females prefer males with yellow skin. Propose a hypothesis to explain how such differences could have arisen in allopatric versus sympatric populations.

viridianbear96

1)The use of deceptive signals is common in nature. Certainorchids, for example, lure pollinator wasps with flower petals thatsmell like receptive female wasps. This example can be viewed as aDarwinian puzzle because:

a. The proportion of orchid flowers that set fruit as a resultof successful pollination is actually pretty small.

b. Discriminating male wasps should be favoured by naturalselection so that they do not waste time, energy, and even sperm onorchid flowers.

c. Time and energy spent on orchids reduces the capacity of thewasp population to grow, since the deceptive plants slow theability of male wasps to fertilize all the eggs of theirfemales.

d. It is next to impossible to figure out how orchid flowersevolved to smell like the females of certain wasps.

2) During courtship, the males of some spider species offertheir mates a nuptial gift, a prey item, usually an insect of somekind, such as a cricket. Mating success for the male is highlydependent on the female accepting the gift. Researchers also notedthat males used white silk to wrap the generally dark-colouredgifts just as mated females do with their eggs sacs and wondered ifmales did this intentionally. (4 marks)

i. The last sentence in the paragraph above constitutes:

a. A causal question.

b. A hypothesis.

c. A prediction.

d. Test evidence.

ii. What theory was used to explore the courtship behaviourdescribed above?

iii. Which of the following predictions might likely be correct,given the presumption that males might be making their nuptialgifts look like eggs sacs?

a. The time it takes for a female to accept a nuptial giftshould be less for prey covered in silk that has beenexperimentally coloured brown instead of white.

b. Natural silk-covered prey should be comparable in lightreflectance to silken egg sacs

. c. Females should readily grab and hold silken egg sacs thathad been taken from them but then offered back as if they were anuptial gift.

maroonpig282

BIOC54H3 Chapter 10: Chapter 10

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