What does mate choice have to do with extinction? Can you see any differences between these millimeter-long male and female ostracodes (tiny ocean animals)? Microscope photos of fossil ostracodes. (Bottom, left) In this species of tiny animal called an ostracod, males are smaller than females and have special light organs that they use to compete for females by emitting flashes of bioluminesence. (Gene Hunt, Smithsonian/Jim G. Morin)
What does mate choice have to do with extinction?
Lexile

In the animal kingdom, sexual reproduction is the rule. This is even true for tiny ocean animals. One example is ostracodes. There are just a few exceptions to the rule. Male sex cells must fertilize female sex cells. That is how they make offspring. Some animals, such as male and female clams, release sex cells into the water for chance encounters. But reproduction in many animals requires that males and females find each other. 
 
Attracting individuals of the same species is achieved in a startling variety of ways. They can make creative use of the senses. This activity takes many forms. It can range from singing by frogs to dancing by jumping spiders. There is even luminescing by deep-sea animals. Once found, a potential mate may need to be convinced to go forward with the mating relationship. Generally, it's the male doing the convincing. This is because females usually make the larger investment in creating and raising offspring. So females are choosier about who to mate with.
 
Let's take birds as an example. In birds, males invite females to their territories by singing. They sport bright feathers and do courtship dances. The more flamboyant males tend to be more successful at attracting females. This activity by males drives a sort of evolutionary arms race. Which one can have the showiest feather plumage? Showier plumage may lead to more mating opportunities. This leads to more offspring. That perpetuates showier plumage in the population of birds.
 
This form of natural selection driven by mate choice has a name. It is called "sexual selection." It has inspired spectacular characteristics in animals, from feathers to antlers to lion manes. It also might have a dark side. Peacocks with larger tails may be easier for wild dogs to catch, for example. Elks with larger antlers might not be as agile against wolf attacks. And a lit-up squid might attract a hungry fish instead of a mate. Species with more extreme differences between males and females might be more susceptible to extinction in the long run.
 
Dr. Gene Hunt is a Smithsonian paleontologist. He uses tiny ocean ostracodes as a model to examine a hypothesis. It is that sexual selection plays a role in extinction. You can learn more about what his studies of ostracodes are revealing. Watch a live "Smithsonian Science How" webcast. It airs on Thursday, Feb. 9.  In "What Tiny Marine Fossils Reveal about Extinction" (at 11 a.m. and 2 p.m. EST on the Q?rius website), Gene will show you how he tests hypotheses. He also will answer your questions. You can also get teaching resources to use with the webcast.

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CRITICAL THINKING QUESTION
How might species with more extreme differences between males and females be more susceptible to extinction?
Write your answers in the comments section below


COMMENTS (23)
  • dylanc10-san
    2/22/2017 - 01:11 p.m.

    Cause male are more smarter and boys like different stuff then girls

  • marianav-san
    2/22/2017 - 01:19 p.m.

    They are really cool. And it is really pretty. And they are really amazing

  • vanessar-san
    2/22/2017 - 01:19 p.m.

    Cause other species have different things between males and females because humans have different things that other animals and things don't

  • robertoh1-san
    2/22/2017 - 01:27 p.m.

    The reason why males and females be more susceptible to extinction because male and female animals are extinct. Another reason is because of sexual selection in animals. A third reason is because luminescing in animals.

  • marcob-san
    2/22/2017 - 01:28 p.m.

    Because they either don't have babies, but they should have more babies so that they wont be extinct.

  • brittanym-san
    2/22/2017 - 01:29 p.m.

    They chosen an animal for this year. Is a peacock they have chosen this animal because it's a Sybil for 2017. Cartier had chosen the peacocks for peace. The peacock is a great siblings. And so are the hawks probably they will chose a hawk as the animal next year.

  • mariav-san
    2/22/2017 - 01:31 p.m.

    The thing . What . Ok .,

  • sarynea-san
    2/22/2017 - 01:39 p.m.

    Females and males are different. All people are different they come from different people. They come from different places.

  • michellem-san
    2/22/2017 - 01:39 p.m.

    Maybe because they might be less of people and that it perpetuates showier plumage in the population of bird. This is because females usually make the longer investment in creating and raising offspring.

  • davidf1-san
    2/22/2017 - 01:41 p.m.

    Between male and females is that the boys and girls can't go to the same bathroom.Also girls and boys can't shower together.Next is that girls and boys can't do nothing bad because it's not good.Another one is that kids can't hit each other.

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