Mammalia Class Characteristics Quiz

Questions and Answers

What are characteristics of class Mammalia?

mammary glands, hair, four-chambered hearts, regulated internal body temperature, sweat sebaceous and scent glands, large cerebral cortex, heterodont dentition

What are the subclasses of Mammalia?

prototheria, theria

What are the 3 infraclasses in class Mammalia?

ornithodelphia, metatheria, eutheria

What are the members of each infraclass (Ornith, Metat., Eutheria)?

monotremes, marsupials, placentals Signup and view all the answers

What subclass used to contain the monotremes but now only contains extinct species?

subclass prototheria Signup and view all the answers

Technical characteristics of the _________ distinguish members of subclass theria and infraclass ornithodelphia.

skull Signup and view all the answers

What is the outgroup of mammals?

dog tooth Signup and view all the answers

How many middle ear ossicles do mammals have?

three Signup and view all the answers

What does heterodont dentition mean?

An animal which possesses more than a single tooth morphology. Signup and view all the answers

What are cynodonts?

A carnivorous, mammal-like fossil reptile of the late Permian and Triassic periods, with well-developed, specialized teeth. Signup and view all the answers

What infraclass are the monotremes?

ornithodelphia Signup and view all the answers

What are the monotremes?

Mammals that lay eggs; spiny anteater and the duck-billed platypus. Signup and view all the answers

What is the cloaca? What infraclass has this feature?

Common opening for excretory, digestive, and reproductive products; ornithodelphia. Signup and view all the answers

What infraclass are the marsupials?

Metatheria Signup and view all the answers

What are examples of marsupials?

Kangaroos, koalas, opossums. Signup and view all the answers

What is a marsupium?

Pouch or fold that carries young. Signup and view all the answers

What is adaptive radiation?

The diversification of a group of organisms into forms filling different ecological niches. Signup and view all the answers

What is the ecological placental equivalent to the wombat?

A groundhog. Signup and view all the answers

What is the ecological placental equivalent to the Tasmanian devil?

Wolverine. Signup and view all the answers

What infraclass are the placental mammals?

Eutheria. Signup and view all the answers

What are placental mammals?

Animals that develop for a long time inside the mother's uterus; dominant large terrestrial animals. Signup and view all the answers

Diffusion of nutrients from the mother to an embryo occurs through what?

The placenta. Signup and view all the answers

What is the placenta?

It is the tissue attached to the uterine wall that nourishes the fetus through the umbilical cord. Signup and view all the answers

What helps form the umbilical cord and the placenta?

Chorion, allantois, yolk sac. Signup and view all the answers

True or False? Marsupial young are born larger and more developed than placental young?

False Signup and view all the answers

What are the four types of teeth mammals have (not always all of them together)?

Canine, incisor, premolar, molar. Signup and view all the answers

What is the open space in the jaw/teeth of mammals called?

Diastema. Signup and view all the answers

Carnivorous mammals have _____________ apparatus that are paired upper and lower teeth modified in such a way as to allow enlarged and often self-sharpening edges to pass by each other in a shearing manner.

carnassial Signup and view all the answers

What is a characteristic of mammals that allows breathing while chewing?

Secondary palate. Signup and view all the answers

What is the advantage of chewing food?

Chewing breaks food into tiny pieces which creates more surface area for bacteria to break it down. Signup and view all the answers

What is the most efficient circulatory system?

A four chambered heart. Signup and view all the answers

What does a two chambered heart consist of?

One atria and one ventricle. Signup and view all the answers

What does a four chambered heart consist of?

Two atria and two ventricles. Signup and view all the answers

In a four-chambered heart, the __ atrium receives oxygen-poor blood from the body and pumps it to the _ ventricle. The ____ ventricle pumps the oxygen-poor blood to the lungs.

right, right, right Signup and view all the answers

Study Notes

Characteristics of Class Mammalia

Possess mammary glands for nursing young.
Have hair or fur covering their bodies.
Feature a four-chambered heart for efficient circulation.
Maintain a regulated internal body temperature (homeothermy).
Contain sweat, sebaceous, and scent glands.
Exhibit a large cerebral cortex responsible for complex behavior and learning.
Possess heterodont dentition (different types of teeth).

Subclasses of Mammalia

Classified into two main subclasses: Prototheria and Theria.

Infraclasses in Class Mammalia

Three infraclasses: Ornithodelphia (monotremes), Metatheria (marsupials), Eutheria (placentals).

Members of Each Infraclass

Ornithodelphia includes monotremes like the platypus.
Metatheria encompasses marsupials such as kangaroos and koalas.
Eutheria covers placental mammals, which are characterized by a prolonged gestation period.

Extinct Species of Prototheria

The subclass Prototheria comprises only extinct species; the current monotremes are now categorized under Ornithodelphia.

Identification Features between Subclasses

The skull structure distinguishes members of the subclass Theria from those in Ornithodelphia.

Outgroup of Mammals

The dog tooth serves as the outgroup for mammals.

Middle Ear Ossicles in Mammals

Mammals have three middle ear ossicles, enhancing hearing capabilities.

Heterodont Dentition Explained

Refers to the presence of different tooth types (incisors, canines, premolars, and molars) within the same animal.

Definition of Cynodonts

Cynodonts are carnivorous, mammal-like reptiles from the late Permian and Triassic periods, notable for their specialized teeth.

Infraclass of Monotremes

Monotremes belong to the infraclass Ornithodelphia.

Characteristics of Monotremes

Monotremes are unique mammals that lay eggs; examples include the spiny anteater and the duck-billed platypus.

Cloaca in Monotremes

The cloaca is a common opening for excretory, digestive, and reproductive products; found in the infraclass Ornithodelphia.

Infraclass of Marsupials

Marsupials are classified under the infraclass Metatheria.

Examples of Marsupials

Common marsupials include kangaroos, koalas, and opossums.

Function of the Marsupium

A marsupium is a pouch or fold that carries and protects young marsupials.

Concept of Adaptive Radiation

Adaptive radiation describes the diversification of organisms into various forms that occupy different ecological niches, stemming from a single ancestral species.

Ecological Placental Equivalents

The groundhog is ecologically similar to the wombat.
The wolverine is ecologically comparable to the Tasmanian devil.

Infraclass of Placental Mammals

Placental mammals fall under the infraclass Eutheria.

Definition of Placental Mammals

Placental mammals develop young inside the mother’s uterus, leading to the birth of more developed offspring; they are often large terrestrial animals.

Nutrient Transfer via the Placenta

Nutrient diffusion from the mother to the embryo occurs through the placenta.

Structure and Function of the Placenta

The placenta attaches to the uterine wall and nourishes the fetus through the umbilical cord.

Components Forming the Placenta and Umbilical Cord

Key structures include the chorion, allantois, and yolk sac.

Marsupial Young’s Development at Birth

Marsupial young are born less developed and smaller compared to placental young.

Types of Teeth in Mammals

Mammals typically possess four types of teeth: canines, incisors, premolars, and molars.

Diastema in Mammals

Diastema refers to the open spaces in the jaw between teeth, often found in mammals.

Carnivorous Mammal Adaptations

Carnivorous mammals have a specialized dental apparatus called carnassials for efficient shearing of meat.

Secondary Palate's Role in Mammals

The secondary palate allows mammals to breathe while chewing food, facilitating simultaneous respiration and mastication.

Advantages of Chewing Food

Chewing increases the surface area of food particles, aiding in breakdown by bacteria and enhancing digestion.

Circulatory System Efficiency

A four-chambered heart is the most efficient circulatory system, allowing for separation of oxygenated and deoxygenated blood.

Components of a Two-Chambered Heart

Composed of one atrium and one ventricle, less efficient in separating oxygenated and deoxygenated blood.

Structure of a Four-Chambered Heart

Comprising two atria and two ventricles, facilitating effective oxygenation and circulation of blood throughout the body.

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Description

Test your knowledge on the characteristics and subclasses of class Mammalia. This quiz covers essential features like mammary glands, hair, and the various infraclasses within Mammalia. Perfect for biology students and enthusiasts looking to deepen their understanding of mammals.