ZoologyLesson 3 of 4 in the course Vertebrates

Mammalian Traits, Evolution, and Reproductive Groups

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

Mammals are vertebrates recognized by hair and milk-producing mammary glands. Their other features—from specialized jaws to distinctive organs—help explain how they feed, regulate body temperature, and function as a group.

Hair is made of keratin, the same structural protein found in nails and claws. Even when hair is sparse or inconspicuous, as in whales, it is a defining mammalian feature. Hair traps a layer of air close to the body, helping retain metabolic heat. It can also provide camouflage, contribute to social signals, or stand erect to make an animal appear larger.

All flashcards

What are vibrissae?
Vibrissae are specialized hairs, commonly called whiskers, connected to nerves that detect touch and vibration. They are especially useful to nocturnal and burrowing mammals.
What do sebaceous glands produce, and what does it do?
They produce sebum, a lipid-rich substance that lubricates hair and skin and helps make them water-resistant.
What is the difference between heterodont and diphyodont?
Heterodont mammals have different types of teeth, such as incisors and molars. Diphyodont mammals develop two sets of teeth: deciduous teeth followed by permanent teeth.
How did two jaw bones contribute to mammalian hearing?
The ancestral articular and quadrate bones became the malleus and incus in the middle ear, where they help transmit vibrations toward the inner ear.
What does the corpus callosum do, and which mammals have it?
It connects the cerebral hemispheres and helps integrate their functions. It is present in eutherian mammals.

Quiz questions

  1. What protein makes up mammalian hair?Answer: Keratin
  2. What is the primary function of eccrine sweat evaporation in humans?Answer: Cooling the body
  3. Which mammalian jaw bone became the malleus?Answer: The articular bone
  4. A mammal has incisors, canines, premolars, and molars. What tooth condition does this illustrate?Answer: Heterodonty
  5. Why can a loop of Henle be useful to a mammal living where water is scarce?Answer: It helps the kidneys produce concentrated urine.

Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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