Mammals Chapter 25 Flashcards

Questions and Answers

Describe the hierarchy of the classification of mammals.

Domain: Eukarya, Kingdom: Animalia, Phylum: Chordata, Subclass: Vertebrata, Class: Mammalia.

What are the key features of all mammals?

Mammals have mammary glands, are endothermic, have hair/fur, an efficient 4-chambered heart, large brains, provide parental care (milk), and have specialized teeth.

What is the advantage of being endothermic?

Can internally regulate temperature, allowing survival in colder regions and providing a nourishing environment for live births.

What is the disadvantage of being endothermic?

Endothermic regulation takes energy and requires constant food intake. Signup and view all the answers

Briefly describe the evolution of mammals.

Ancient reptiles split into two groups; one led to modern reptiles & birds (diapsids) and the other to mammals (synapsids). Signup and view all the answers

From what ancestors did mammals evolve?

Synapsids. Signup and view all the answers

What are a carnivore's teeth like?

Carnivores have sharp canines and molars. Signup and view all the answers

What are an omnivore's teeth like?

Omnivores have 'multi-purpose' teeth. Signup and view all the answers

What are a herbivore's teeth like?

Herbivores have flat grinding teeth and/or chisel-like teeth for gnawing. Signup and view all the answers

Name the different types of human teeth.

Incisor, Premolar, Canine, Molars. Signup and view all the answers

Describe the cardiovascular system of mammals.

Mammals have a four-chambered heart and gas exchange occurs in well-developed lungs. Signup and view all the answers

How many bones are there in a mammal's middle ear?

Three. Signup and view all the answers

Mammals are the only animals that can sweat.

False Signup and view all the answers

All mammals sweat.

False Signup and view all the answers

Ancient mammals split into how many groups?

Two. Signup and view all the answers

What does Diapsid mean and what did it lead to?

2 holes on sides of skull; led to modern reptiles & birds. Signup and view all the answers

Give examples of modern diapsid animals.

Alligator and Tuatara. Signup and view all the answers

Give an example of an extinct diapsid animal.

Prestosuchus. Signup and view all the answers

What does Synapsid mean and what did it lead to?

1 hole on sides of skull; led to mammals. Signup and view all the answers

Give examples of modern synapsid animals.

Horse (placental mammal) and Kangaroo (marsupial mammal). Signup and view all the answers

Give an example of an extinct synapsid animal.

Dimetrodon. Signup and view all the answers

What were the earliest synapsid animals?

Pelycosaurs like Dimetrodon (ectothermic reptiles). Signup and view all the answers

What was the second group of synapsids to evolve?

A group called therapsids evolved next. Signup and view all the answers

What are the Monotremes?

The earliest true mammals likely included ancient species of monotremes, which were warm-blooded but egg layers. Signup and view all the answers

What mammal feature did monotremes have?

Warm-blooded. Signup and view all the answers

What feature did monotremes have that were not mammal-like?

They were egg layers. Signup and view all the answers

Evolution of mammals: What happened to the bones in the jaw and face of mammals during evolution?

Mammals' lower jaw became just one bone on each side; other small bones became the inner ear bones. Signup and view all the answers

How does the jaw bone of mammals differ from other vertebrates?

The lower jaw consists of one bone compared to other jawed vertebrates that have multiple bones in the lower jaw. Signup and view all the answers

Mammal diversity: How diverse and how many orders of mammals are there?

Very diverse! There are 29 orders of living mammals. Signup and view all the answers

Mammal diversity: How many Monotremes (Prototherians) mammal orders are there?

One. Signup and view all the answers

Study Notes

Classification of Mammals

Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
- Subclass: Vertebrata
Class: Mammalia

Key Features of Mammals

Possess mammary glands for nursing offspring
Endothermic, allowing temperature regulation
Covered with hair or fur
Four-chambered heart for efficient circulation
Relatively large brains compared to other animals
Provide parental care, including feeding with milk
Specialized teeth adapted to dietary needs

Advantages of Being Endothermic

Can maintain stable body temperature internally
Ability to thrive in colder environments
Supports a nurturing environment for developing young

Disadvantages of Being Endothermic

Requires constant energy to maintain body temperature
High metabolic rate leading to need for continuous food intake

Evolution of Mammals

Ancient reptiles divided into two main groups:
- Diapsids, leading to modern reptiles and birds (characterized by two skull holes)
- Synapsids, leading to mammals (characterized by one skull hole)

Types of Mammal Teeth

Carnivores: Sharp canines and molars for tearing meat
Omnivores: Versatile 'multi-purpose' teeth
Herbivores: Flat grinding teeth or chisel-like teeth for plant material

Cardiovascular System

Four-chambered heart structure
Well-developed lungs facilitating gas exchange
Complete separation of oxygenated and deoxygenated blood

Middle Ear Structure

Mammals are unique among vertebrates with three bones in the middle ear.

Sweat and Thermoregulation

Only mammals can sweat, serving as a thermoregulatory feature.
Not all mammals have the ability to sweat, indicating variability in this trait.

Groups of Synapsids

Earliest synapsids: Pelycosaurs, e.g., Dimetrodon, are ectothermic reptiles.
Second group: Therapsids, displaying more mammalian characteristics.

Monotremes

Ancient true mammals believed to be monotremes: warm-blooded but lay eggs.
Unique feature of monotremes includes egg-laying, unlike typical mammals.

Jaw Bone Evolution

Evolution led to a singular bone structure in the lower jaw of mammals.
Small bones from the jaw adapted into the inner ear bones.

Diversity of Mammals

Mammalian diversity is extensive, encompassing 29 recognized orders.
Only one order exists for monotremes (Prototherians).

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Description

Test your knowledge about the classification and key features of mammals with these flashcards covering Chapter 25. Learn about the hierarchy, including domains and classes, and the unique characteristics that define mammals.