Marine biologyLesson 2 of 4 in the course Marine animals

Marine Mammals: Evolution, Ecology, Adaptations, and Conservation

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

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Summary

Marine mammals are a varied group of mammals whose lives depend on marine ecosystems. This lesson introduces the major groups, explains how their dependence on water differs, and outlines key points in their evolutionary history.

Marine mammals are an informal ecological group, not one single taxonomic branch. They are grouped together because they rely on marine environments for feeding and survival. The group includes cetaceans (whales, dolphins, and porpoises), sirenians (manatees and dugongs), pinnipeds (seals, sea lions, and walruses), sea otters, marine otters, and polar bears.

All flashcards

Informal ecological group
A grouping based on shared reliance on marine environments, rather than membership in one taxonomic lineage.
Quasi-marine mammal
A mammal that depends on marine resources or habitats without the specialized aquatic adaptations of principal marine mammal groups.
Cetartiodactyla
A combined term reflecting the evolutionary relationship between cetaceans and even-toed ungulates.
Counter-current heat exchange
A circulatory arrangement that conserves heat by transferring it between blood flowing in opposite directions.
Whale fall
A whale carcass on the seafloor that provides food and habitat for deep-sea communities.

Quiz questions

  1. What primarily defines marine mammals as an informal ecological group?Answer: Their reliance on marine environments for feeding and survival.
  2. Which two groups are fully aquatic and must live in water?Answer: Cetaceans and sirenians.
  3. Which living land mammals are considered the closest relatives of cetaceans?Answer: Hippopotamuses.
  4. How does the whale pump move nutrients toward surface waters?Answer: Whales feed at depth and release nutrient-rich feces near the surface.
  5. What does the U.S. Marine Mammal Protection Act generally require for taking marine mammals?Answer: An authorized permit for activities such as hunting, capture, or harassment.

Based on the Wikipedia article Marine mammal, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.

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