Question

3. Female birds who practice polyandry might see benefits if they obtained genes from several partners who are particularly compatible with the genes in their eggs. If the preceding sentence is a hypothesis, what prediction follows? (2 marks)

   1. Typically, females in the population will mate with the same very few males.

   2. The males chosen as reproductive partners will vary substantially from female to female.

   3. Males of this particular species are more likely to exhibit lek polygyny.

   4. Females exhibiting polyandry will obtain more material benefits from their mates than monogamous females.

7. Trochilidae (or Hummingbirds) have evolved as specialist nectar eaters. Up to 90% of aHummingbird’s diet can consist of nectar. Their beaks, which are particularly slender and long, are well adapted for obtaining nectar. For example, the buff-tailed sicklebill (Eutoxeres condamini) has a curved beak, which supports its feeding on tube-like flowers, like Heliconias. Even their tongue is long – twice as long as the bill – so that they can reach even further down the tube! Researchers of this hummingbird have observed that individualbirds practice ‘circuits’, or patterns, from one flower to the next as they feed. Over a 30minute period, an individual bird could make one entire circuit, ending back at the flower it started with. Given what you have learned in this course, consider each of the following:(total 6 marks, 2 marks each)

1. If a researcher observed this behaviour and assumed that the bird was showing optimal behaviour by obtaining more energy than it is using, s/he may be wrong. Why?

2. If you were a researcher who wanted to collect data in order to measure whether or not the hummingbird was behaving optimally while foraging, what are some examples of foraging behaviour you would need to track if your goal was to calculate the net caloric gain for the foraging hummer?

3. Researchers have also observed that hummingbirds may pause before they actually insert their beaks into the flowers. Could this behaviour be consistent with a hypothesis that suggests the bird is foraging optimally? Why or why not?

Answer 1

According to the hypothesis, the following statement holds true

Males chosen as reproductive partners will vary substantially from female to female. This because the female selects a mate which is more variable genetically. Thus individual females select mates according to their genetic make up.

All are other statements are false according to the hypothesis.

Typically, females in the population mate with the same very few males. In polyandrous system one female mates with many males.

Males of this particular species are more likely to exhibit lek polygyny. Lek mating is observrd in polygynous species.

Females exhibiting polyandry will obtain more material benefits from their mates than monogamous females.The hypothesis does not imply any material benefits but associates polyandrous system as way to increase diversity genetic diversity