32 Questions
What is one of the adaptations in mammals that allows for greater sideways flexion and up and down flexion?
Fewer ribs attached to the spine
What is the function of the Loop of Henle in the kidney?
To concentrate urine and facilitate water and ion retention
What is a characteristic of the urogenital system of marsupials?
Common urogenital opening and two lateral vaginas
What is the function of specialized skin glands in mammals?
To facilitate communication and rearing of offspring
What is a characteristic of the penis shape in many male marsupials?
Bifurcated
What is a characteristic of placental mammals?
Three separate openings for the urogenital system
What is a characteristic of the vertebral column in mammals?
Fewer ribs attached to the spine
What is a characteristic of monotremes?
Laying eggs
What is the primary function of the placenta in mammals?
To provide nourishment to the developing embryo
Which of the following characteristics is shared by all mammals, but not necessarily by other taxonomic groups?
Three inner ear ossicles
What is the term for the maintenance of a relatively constant body temperature in mammals?
Homeothermy
Which type of placenta is characteristic of marsupials?
Choriovitelline placenta
What is the term for the growth of teeth continuously throughout life?
Diphodonty
Which of the following is NOT a characteristic of monotremes?
Have proper nipples
What is the consequence of endothermy and homeothermy in mammals?
Increased energy expenditure
Which of the following is a characteristic of mammalian red blood cells?
Enucleated
What is the primary function of the muscular diaphragm in mammals?
To facilitate breathing
Which characteristic is unique to placental mammals?
Chorioallantoic placenta
What is the significance of fur in mammals?
It helps in thermoregulation
Which of the following is a characteristic of mammalian dental morphology?
Heterodonty
What is the consequence of endothermy and homeothermy in mammals?
Increased energy expenditure
Which of the following is a characteristic shared by all mammals?
Three inner ear ossicles
In which group of mammals do males lactate?
Some species of fruit bats
What is the characteristic feature of mammalian red blood cells?
Enucleated
What is a characteristic of the four-chambered heart found in mammals?
Efficient separation of oxygenated and deoxygenated blood
Which feature of the vertebral column allows for greater flexibility in mammals?
Decrease in the number of ribs attached to the spine
What is the primary function of the secondary palate in mammals?
To separate breathing and eating, and facilitate improved communication
Which feature of the skeletal system is characteristic of digitigrade posture in many mammals?
Upright stance
What is the primary function of the complex lung in mammals?
To increase the efficiency of gaseous exchange
What is a characteristic of the urogenital system of placental mammals?
Three separate openings
What is the primary function of specialized skin glands in mammals?
To aid in communication, and rearing of offspring
Which group of mammals lays eggs?
Monotremes only, such as platypus and echidnas
Study Notes
Mammal Characteristics
- There are 11 mammal-specific characteristics that distinguish mammals from other animals.
- Three major mammal groups are: monotremes, marsupials, and placental mammals.
Body Features
- Mammals have fur, which may be highly specialized or appear to be absent, but always present in some form.
- Single bone in the lower jaw is a characteristic of mammals.
- Heterodonty is present in some mammals, with some species being secondarily homodontic or having lost teeth altogether.
- Dentary-squamosal jaw articulation is a unique feature of mammals.
Reproductive Features
- Placenta is present in mammals, with marsupials having a choriovitelline placenta and placental mammals having a chorioallantoic placenta.
- This difference in placenta development results in marsupial young being born at a very early stage of development.
- Mammae are present in all mammals, with milk secretion being a characteristic of mammals.
Circulatory System
- Single major artery leaves the heart and branches to the left in mammals.
- Enucleated red blood cells are a characteristic of mammals.
Other Characteristics
- Basic body plan of mammals includes a backbone/spinal column, bilaterally symmetrical body, and four limbs.
- Endothermy and homeothermy are present in mammals, allowing them to colonize 'hostile' habitats.
- Maintenance of a relatively constant body temperature requires lots of energy and is associated with changes in features involved with food acquisition, processing, and waste elimination.
Skeletal Features
- Changes to the vertebral column include fewer ribs attached to the spine, reducing body mass and allowing for greater flexibility.
- Cranial changes include a secondary palate, which separates breathing and eating and facilitates improved communication.
Cardio-Vascular System
- Mammals have a four-chambered heart, which is also seen in birds and some reptiles.
Respiratory System
- Complex lung increases the efficiency of gaseous exchange.
Urogenital System
- Waste excretion is facilitated by the Loop of Henle in the kidney, allowing for concentrated urine and water and ion retention.
- Monotremes have a single external opening, while marsupials have separate exits for the alimentary canal and a common urogenital opening, and placental mammals have three separate openings.
Skin and Other Features
- Skin glands are specialized for temperature regulation and are also used in communication and rearing of offspring.
- Viviparity (birth of live young) is seen in some mammals, while others are oviparous (egg-laying).
Mammal Characteristics
- There are 11 mammal-specific characteristics that distinguish mammals from other animals.
- Three major mammal groups are: monotremes, marsupials, and placental mammals.
Body Features
- Mammals have fur, which may be highly specialized or appear to be absent, but always present in some form.
- Single bone in the lower jaw is a characteristic of mammals.
- Heterodonty is present in some mammals, with some species being secondarily homodontic or having lost teeth altogether.
- Dentary-squamosal jaw articulation is a unique feature of mammals.
Reproductive Features
- Placenta is present in mammals, with marsupials having a choriovitelline placenta and placental mammals having a chorioallantoic placenta.
- This difference in placenta development results in marsupial young being born at a very early stage of development.
- Mammae are present in all mammals, with milk secretion being a characteristic of mammals.
Circulatory System
- Single major artery leaves the heart and branches to the left in mammals.
- Enucleated red blood cells are a characteristic of mammals.
Other Characteristics
- Basic body plan of mammals includes a backbone/spinal column, bilaterally symmetrical body, and four limbs.
- Endothermy and homeothermy are present in mammals, allowing them to colonize 'hostile' habitats.
- Maintenance of a relatively constant body temperature requires lots of energy and is associated with changes in features involved with food acquisition, processing, and waste elimination.
Skeletal Features
- Changes to the vertebral column include fewer ribs attached to the spine, reducing body mass and allowing for greater flexibility.
- Cranial changes include a secondary palate, which separates breathing and eating and facilitates improved communication.
Cardio-Vascular System
- Mammals have a four-chambered heart, which is also seen in birds and some reptiles.
Respiratory System
- Complex lung increases the efficiency of gaseous exchange.
Urogenital System
- Waste excretion is facilitated by the Loop of Henle in the kidney, allowing for concentrated urine and water and ion retention.
- Monotremes have a single external opening, while marsupials have separate exits for the alimentary canal and a common urogenital opening, and placental mammals have three separate openings.
Skin and Other Features
- Skin glands are specialized for temperature regulation and are also used in communication and rearing of offspring.
- Viviparity (birth of live young) is seen in some mammals, while others are oviparous (egg-laying).
Learn about the unique characteristics of mammals, including body features such as fur and jaw structure, and the three major mammal groups: monotremes, marsupials, and placental mammals.
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