AB week8
Mating Systems
key concepts: monogamy, polygamy, polygyny, polyandry, lek
Part 1: Write your respond and 1st subject and use the own words. (200-250 words)
We're going to discuss mating systems this week. You're familiar with monogamy, and I'm sure you've heard of bigamy, which is the legal term for polygamy (multiple spouses). Usually when you think of polygamy, you think of one man and multiple wives (polygyny). But in some cultures, it is more common to have one woman and multiple husbands (polyandry). Let's start this week by discussing polyandry in human cultures: where, when, and why is it practiced? Here are several resources, which should have enough material so that everyone can contribute to the discussion. (Please focus on one idea in your post, and please avoid repeating what others have said.)
Watch those videos.
https://www.youtube.com/watch?v=d4yjrDSvze0
https://www.theatlantic.com/health/archive/2013/02/when-taking-multiple-husbands-makes-sense/272726/
https://www.youtube.com/watch?v=U6bYCi-1wF4
can look into polyandry in non-human animals, like the jacana https://www.youtube.com/watch?v=2l72DHdaK94
(or lily trotter). Besides being polyandrous, what else is unusual about these birds? Why do researchers think the jacana is polyandrous? (You can find a brief answer here https://www.pbs.org/wgbh/evolution/library/01/6/l_016_04.html
, but see if you can expand on the idea.)
Write your respond and 1st subject and use the own words. (200-250 words)
Part 2:
1. https://www.youtube.com/watch?v=RqBWKBgvdYo Watch the video, Among our closest primate relatives (chimps, gorillas, bonobos), how many are monogamous?
Top of Form
A : all
B : one
C : none
2. https://www.youtube.com/watch?v=19jvDaUWqBw Watch the video, In the video, the male cuttlefish guards his mate by
Top of Form
A : swimming very close to her
B : grasping her
C : attacking a rival male
D : all of the above
Bottom of Form
3. https://video.nationalgeographic.com/video/00000144-0a34-d3cb-a96c-7b3d3ad40000 Watch the video, How does the male angler fish ensure that he won't lose his mate
Top of Form
A : his swims behind her
B : he merges his body into hers
C : he creates a burrow for her to live in
Bottom of Form
Monogamy is the norm in most human societies, but it is rare among animals. The more common mating system is polygyny: one male mating with multiple females. Males use a wide range of strategies to gain access to multiple females. Let's look at a few of these strategies: (1) Resource defense polygyny Males may defend a valuable resource like high-quality food or nesting locations and use this resource to attract mates. For example, male marmots dig large burrows, and they use these homes to attract multiple mates. (2) Female defense polygyny If females gather either because they are herd animals or because they access the same resource (e.g. a beach to breed), males may try to defend groups of females, called harems. Examples include elephant seals and mountain goats. (3) Lekking Males may also try to attract multiple mates by their sheer fabulousness. In some species, males display themselves or their handiwork in an attempt to attract females. Often the males gather at the same display ground, called a lek, but in some species the males are dispersed. Lekking males provide no resources to the females or their offspring, so the females are simply looking for "high quality" males that have good genes and good health (healthy animals are less likely to pass on a parasite or illness). Lekking males often put on quite a show; let's look at one of the more extreme cases. In western states with sagebrush areas, male sage grouse gather in groups of 20-30 individuals. Alpha males stake out a territory in the center of the lek, while lower ranking males make due with small areas on the periphery of the lek.
4. How many displays might a female sage grouse listen to when sizing up a male?
Top of Form
A : 3
B : 12
C : 20
D : hundreds
Bottom of Form
5. https://www.youtube.com/watch?v=rafdHxBwIbQ Watch the video, Why doesn't one type of male dominate?
Top of Form
A : because each allele occurs with equal fequency
B : because females prefer whichever type is uncommon.
C : because predators learn to hunt for the common type
Bottom of Form
Part 3: Answer Q1-3 and explain.
For each of the following species, use the concepts from the background material to pick the most likely mating system. Pick one:
· Female defense polygyny
· Resource defense polygyny
· Lek polygyny
· Monogamy
1. The kakapo is a flightless parrot. The females of this species raise their young without any help from the males. Just before the breeding season, males go to a central area and dig large holes in the ground. (The holes are not nests - remember, the males provide nothing.) Throughout the breeding season, the males sit in the holes and make loud, low-frequency booming sounds to attract females.
2. Narwhals are marine mammals in which the females live in groups and males have a large tusk.
3. In some vole species (voles are small rodents), newborns are blind, hairless, and unable to regulate their body temperature. For newborns to thrive, an adult must warm them continuously for several days. These voles also live in areas where food is relatively scarce.
Part 4: Write a respond for the questions (Use 1st subject and use the own words) (200 words)
Researchers have compared the size and shape of human male genitals to those of other primates. https://www.youtube.com/watch?v=2WdnkzcBddA
They've used the results to infer the mating system of early hominids. What have researchers observed? What conclusions have the drawn? What should we make of these conclusions? If we've thoroughly answered these questions, you can also discuss what is known about the size and shape of the genitals of other animals: the evolution of genitalia https://www.youtube.com/watch?v=vcPJkz-D5II
Your post should be focused, relevant, and specific.