5a. Define each of the 3 categories of mammals: Eutherians Marsupials Monotremes:

Biology (MindTap Course List)
11th Edition
ISBN:9781337392938
Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg
Publisher:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg
Chapter31: Sponges, Cnidarians, Ctenophores, And Protostomes
Section: Chapter Questions
Problem 7TYU: Which of the following characteristics is associated with mollusks? (a) mandibles (b) mantle (c)...
icon
Related questions
Question

5a. Define each of the 3 categories of mammals:

  • Eutherians
  • Marsupials
  • Monotremes:
Expert Solution
Step 1

Mammals belong to the class Mammalia. They are the warm-blooded animals and rule the terrestrial ecosystem. They are the largest (like a whale) and the most intelligent animals (like humans) on the planet. They have some typical characteristics like the presence of backbone, four-chambered heart, hair, neocortex, and three middle ear bones. They also contain mammary glands to secrete milk and feed the young ones.

Step 2

Based on their mechanism of baby’s development, they are divided into three groups:

  1. Prototheria – They are also termed as monotremes. They are almost extinct now but are the only mammals that lay eggs. Only 5 species of them are alive now, which are, anteater, platypus, Tasmania, and New Guinea. They have a single hole, that is, through the same hole they lay eggs and pass out the waste products. They maintain their body temperature at 32°C.
  2. Marsupials – They are also termed as Metatheria. They are mostly found in Australia, with 200 species there alone. The examples of marsupials are kangaroos, opossums, and koalas. They contain pouches in their belly, termed as marsupium, to protect and sustain the younger ones. They maintain their body temperature at 35°C.
  3. Eutheria – They are also termed as placental mammals. They dominate the planet and are found everywhere. They are Rodentia, Chiroptera, Carnivora, and cetartiodactyls. Their body temperature is maintained at 38°C and has a high metabolic rate. They have a separate opening at the bottom of the pelvis to give the birth to young ones. In them, the fetus is present in the uterus of the mother. The fetus is nourished by placenta until the birth.
steps

Step by step

Solved in 3 steps

Blurred answer
Knowledge Booster
Primate evolution
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
Biology (MindTap Course List)
Biology (MindTap Course List)
Biology
ISBN:
9781337392938
Author:
Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg
Publisher:
Cengage Learning