Mammals: Characteristics and Subclasses

Study Notes

Mammals

Characteristics:

Warm-blooded (endothermic)
Hair or fur
Mammary glands for milk production
Three middle ear bones (ossicles)
Live birth (viviparity)
Brain development: neocortex, cerebrum, and cerebellum

Subclasses:

Prototheria: monotremes (egg-laying mammals)
- Examples: platypus, echidna
Theria: placental mammals and marsupials
- Metatheria: marsupials (pouched mammals)
  - Examples: kangaroo, koala, opossum
- Eutheria: placental mammals
  - Examples: humans, primates, rodents, carnivores

Body Structure:

Skeletal System: diaphragm, sternum, and pelvis
Muscular System: voluntary and involuntary muscles
Nervous System: central nervous system (CNS) and peripheral nervous system (PNS)

Diversification:

Evolutionary Adaptations: development of limbs, adaptation to environments (e.g., aquatic, terrestrial, aerial)
Dietary Specializations: herbivory, carnivory, omnivory, and insectivory

Examples of Mammals:

Primates: humans, chimpanzees, gorillas
Carnivores: lions, tigers, bears
Ungulates: horses, cows, pigs
Rodents: mice, rats, squirrels
Marine mammals: whales, dolphins, seals

Mammals

Characteristics

Mammals are warm-blooded, meaning they regulate their own body temperature
They have hair or fur, which helps to regulate body temperature and protect their skin
Mammary glands are present in females, producing milk for their young
Three middle ear bones (ossicles) are present, enabling them to hear more effectively
Mammals give birth to live young, as opposed to laying eggs
They have a highly developed brain, consisting of the neocortex, cerebrum, and cerebellum

Classification

Prototheria

This subclass consists of monotremes, which are mammals that lay eggs
Examples include platypus and echidna

Theria

This subclass includes placental mammals and marsupials
Metatheria: marsupials, which are pouched mammals
- Examples include kangaroo, koala, and opossum
Eutheria: placental mammals
- Examples include humans, primates, rodents, and carnivores

Body Structure

The skeletal system consists of a diaphragm, sternum, and pelvis
The muscular system includes both voluntary and involuntary muscles
The nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS)

Diversification

Mammals have evolved various adaptations to their environments, such as the development of limbs and specializations for aquatic, terrestrial, and aerial habitats
They have also developed diverse diets, including herbivory, carnivory, omnivory, and insectivory

Examples of Mammals

Primates include humans, chimpanzees, and gorillas
Carnivores include lions, tigers, and bears
Ungulates include horses, cows, and pigs
Rodents include mice, rats, and squirrels
Marine mammals include whales, dolphins, and seals

Description

Learn about the key characteristics of mammals, including being warm-blooded and having hair or fur, as well as their subclasses such as monotremes, marsupials, and placental mammals. This quiz covers the basics of mammalian biology.