Mammals Overview Quiz

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Questions and Answers

What substance primarily composes rhinoceros horns?

Keratinised filaments (correct)

Bone tissue

Cartilage

Collagen fibers

Which statement about mammalian endothermy is true?

All mammals are exothermic.

Mammals require less food energy than reptiles.

Mammals need to eat more food than reptiles weight for weight. (correct)

Endothermy is unique to mammals.

What is the primary function of eccrine sweat glands?

To produce heat

To secrete milky fluid

To cool the skin (correct)

To enhance hair quality

In humans, where are apocrine glands mainly located?

In the armpits and pubic mound Signup and view all the answers

What differentiates sebaceous glands from other integumentary glands in mammals?

They are associated with hair follicles. Signup and view all the answers

What is the primary role of scent glands in mammals?

Territorial marking and communication Signup and view all the answers

How do mammary glands develop in female mammals?

By thickening of the epidermis along the milk line Signup and view all the answers

Which of the following best characterizes the naked mole rat?

It exhibits exothermic (cold-blooded) characteristics. Signup and view all the answers

What characterizes the gestation period of viviparous placental mammals compared to marsupials?

Long gestation vs. prolonged lactation Signup and view all the answers

Which type of placenta initially supplies nourishment to the embryo in viviparous placental mammals?

Choriovitelline placenta Signup and view all the answers

Which statement about gestation periods in mammals is true?

Gestation tends to increase with size but has notable exceptions. Signup and view all the answers

What is typically true about the number of young produced by small mammals?

They tend to have numerous young to offset high mortality rates. Signup and view all the answers

How does the dependency of young mammals on their mothers benefit their development?

It facilitates non-genetic transfer of knowledge through training. Signup and view all the answers

What is one advantage of increased brain complexity in mammals?

It allows the individual to respond to short-term changes more efficiently than genetic changes. Signup and view all the answers

Which of the following statements is false regarding the birth condition of young mammals?

All mammals give birth to fully formed young. Signup and view all the answers

Which type of social structure do some mammals exhibit?

They form social groups but are generally solitary otherwise. Signup and view all the answers

What additional role do mammary glands serve in humans beyond feeding the young?

Sexual role Signup and view all the answers

How do most mammals secrete milk from their mammary glands?

Via nipples or teats Signup and view all the answers

Which group of mammals can be categorized as opportunistic feeders?

Insectivores Signup and view all the answers

What is the term used for mammals that exhibit differentiated dentition?

Heterodonts Signup and view all the answers

Which type of teeth is primarily used for biting and snipping?

Incisors Signup and view all the answers

Which trophic category do shrews and moles belong to?

Insectivores Signup and view all the answers

What is a key characteristic of herbivores in terms of their diet?

They feed exclusively on vegetation. Signup and view all the answers

Which of the following mammals belongs to the category of gnawers?

Rabbit Signup and view all the answers

What term was previously used to describe pelycosaurs and therapsids?

Mammal-like reptiles Signup and view all the answers

Which feature is NOT associated with cynodont evolution supporting a high metabolic rate?

Webbed feet Signup and view all the answers

What adaptation allowed the earliest mammals to suckle while breathing?

Secondary bony palate Signup and view all the answers

What characteristic did early mammals possess compared to modern placental mammals?

Lower body temperature Signup and view all the answers

What happened to the main lower jawbone during evolution from therapsid to mammal?

Replaced by the dentary Signup and view all the answers

What was a likely trigger for the synapsids' evolution into early mammals?

Movement to a nocturnal niche Signup and view all the answers

What role did hair play for early mammals?

Promoting heat loss Signup and view all the answers

Following the Permian extinction, which group began to dominate during the Mesozoic Era?

Diapsid archosaurs Signup and view all the answers

What is the approximate number of mammal species compared to fish species?

4600 species to 24,600 species Signup and view all the answers

Which mammal has the smallest known weight?

Kitti's hog-nosed bat Signup and view all the answers

What major factor has influenced mammals more than any other animal group?

Human presence Signup and view all the answers

What is the most numerous domestic animal globally?

Chickens Signup and view all the answers

What is one consequence of introducing alien mammals into new habitats?

Often results in poor outcomes Signup and view all the answers

Which mammal species was officially exterminated in a policy affecting Native Americans?

American bison Signup and view all the answers

What has contributed to the potential collapse of the whaling industry?

Depletion of their resources Signup and view all the answers

What is a current impact of the ever-growing human population on mammals?

Decrease in habitat areas Signup and view all the answers

Study Notes

Overview of Mammals

Mammals are an incredibly diverse group with approximately 4,600 species, significantly smaller than birds (9,000 species), fish (24,600 species), and insects (800,000 species).
They inhabit nearly every environment on Earth and exhibit a wide range of adaptations, size, and form.

Size Variation

Size varies dramatically; examples include the Kitti's hog-nosed bat at 1.5 grams and blue whales exceeding 130 tonnes.

Human Interaction

Mammals have been heavily influenced by humans, who have domesticated many for food, clothing, and companionship.
In 2005, global statistics indicated:
- 1.3 billion domestic cattle
- 960 million pigs
- 54 million horses
- 808 million goats
- 1 billion sheep
- Most numerous is the chicken with 16 billion individuals.

Environmental Impact and Extinction

Human activity has led to the extinction of several mammals, such as the aurochs and the Tasmanian wolf.
Over-exploitation, such as in the whaling industry, poses a threat to mammalian populations and resources.
Habitat destruction due to growing human populations continues to impact mammal survival.

Evolutionary History

Early mammal lineages, such as therapsids, adapted post-Permian extinction, showcasing features for high metabolic rates.
Critical adaptations in mammals include:
- Increased jaw musculature for strong bites.
- Skeletal changes enhancing mobility.
- Turbinate bones aiding heat retention.

Temperature Regulation

Most mammals are endothermic (warm-blooded) and utilize hair for insulation; a few exceptions include the naked mole rat, which is exothermic.

Integumentary Glands

Mammals possess a diverse range of integumentary glands, including sweat, scent, sebaceous, and mammary glands, which serve various purposes like cooling, communication, and reproduction.

Feeding and Diet

Dentition is closely linked to diet, providing insights into feeding habits.
Most mammals have two sets of teeth (deciduous and permanent) and are heterodonts, signifying specialized adaptations for different diets.
Mammals can be classified as:
- Insectivores
- Herbivores
- Carnivores
- Omnivores

Reproductive Strategies

Eutherians (placental mammals) have significant reproductive investment focused on longer gestation periods.
Gestation lengths vary greatly by species, with larger animals generally having longer gestation.
Species such as elephants may produce four calves over their lifetimes, signifying reproductive strategy diversity.

Maternal care allows young mammals to learn from adults, enhancing their adaptability and survival skills.
Some mammals are solitary, while others form social groups for protection and social learning.
Behavioral flexibility and increased brain complexity in mammals are key to their evolutionary success, allowing for efficient responses to environmental changes.

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Description

Test your knowledge about the diverse class Mammalia! This quiz covers their unique characteristics, adaptations, and the ecological niches they occupy. Learn interesting facts about the variety of mammals and their biological differentiation.