How Mammal Jaw Bones Evolved into Ears | Summary and Q&A

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December 6, 2019
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How Mammal Jaw Bones Evolved into Ears

TL;DR

Researchers have discovered a new fossil, Jeholbaatar kielanae, which provides insights into the evolution of mammalian ears and jaw bones.

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Key Insights

  • πŸ˜‚ Jeholbaatar kielanae is a fossil species from the Cretaceous period in China that offers insights into the evolution of mammalian ears and jaw bones.
  • 🦻 Mammalian ears have three middle ear bones, enabling better hearing and the detection of higher frequencies.
  • πŸ‘‚ The movement of jaw bones towards the ears in Jeholbaatar improved its grinding power and made it easier to hear over the sound of chewing.
  • πŸ˜‚ The findings suggest a possible connection between diet and the evolution of mammalian middle ears.
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Transcript

[β™ͺ INTRO] Last week in the journal Nature, researchers announced that they’ve found a new fossil that might help us understand one of the most unique features of mammals: our ears. Also, the little guy is, like, really cute... so there' that. Called Jeholbaatar kielanae, this animal was found by paleontologists in Northeast China. It lived in the C... Read More

Questions & Answers

Q: What is the significance of the fossil species Jeholbaatar kielanae?

The discovery of Jeholbaatar kielanae provides valuable information about the evolution of mammalian ears and jaw bones during the Cretaceous period.

Q: What are the unique features of mammalian ears that set them apart from reptiles?

Mammalian ears have three middle ear bones (malleus, incus, and stapes) compared to reptiles, which typically have only one bone (stapes). This allows mammals to have better hearing and detect higher frequencies.

Q: How did the movement of jaw bones towards the ears in Jeholbaatar contribute to its diet?

By shifting the bone towards the ears, Jeholbaatar could chew in a unique, forwards-and-backwards motion. This improved grinding power and made it easier for the animal to hear over the sound of its chewing, enhancing its feeding abilities.

Q: Does the evolution of Jeholbaatar's ears explain the development of mammalian middle ears?

No, Jeholbaatar's group is a cousin to our mammal group, not an ancestor. However, it presents a new hypothesis for the evolution of jaw bones into ears and provides insights into the success of multituberculates.

Summary & Key Takeaways

  • Paleontologists have discovered a new fossil species, Jeholbaatar kielanae, from the Cretaceous period in China.

  • The fossil's preserved ear bones offer insights into the evolution of mammalian ears, which have unique, complex middle ear bones.

  • Research suggests that the movement of jaw bones towards the ears in Jeholbaatar may have been a result of its diet and improved grinding power.

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