1. Characteristics of Mammals

2. Key Characteristics of Mammals
All mammals have the following in common:
Are endothermic
Hair
Specialized teeth
Females produce milk in mammary glands to nourish live young

3. Mammals and Hair Mammals are the only animals that have hair
Primary function of hair is insulation
Other functions of hair include:
Helping animals blend into their surroundings
Using its hair for advertising
Black and white hair on a skunk warns predators to stay away
Specialized hair serve as a sensory function
Whiskers on cats and dogs are sensitive to touch

4. Endothermy Mammals are endothermic (warm-blooded)
Are animals that can maintain a constant body temperature despite the changes in the environment
Endothermy allows animals to live in cold environments

5. Endothermy Endothermy enables mammals to be very active
Movement for long periods of time requires a lot of energy and a high metabolism
A mammal needs to eat 10x as much food as an ectotherm of similar sizes
Metabolizing food requires a lot of oxygen

6. Endothermy
The respiratory and circulatory systems of mammals are adapted to endothermy
They acquire and distribute oxygen more efficiently than the respiratory and circulatory systems of ectoderms do

7. Respiratory System
Mammal lungs have a larger surface area than reptiles and amphibians
Mammals can exchange more oxygen and carbon dioxide in each breath

8. Respiratory System The Diaphragm aids mammals in breathing
The diaphragm is a sheet of muscle that separates the chest cavity from the abdominal cavity
When the diaphragm contracts , the chest cavity enlarges and air is drawn into the lungs

9. Circulatory System Mammals have a four-chambered heart
A septum completely divides the ventricle
The left ventricle pumps oxygen-rich blood to the body
The right ventricle pumps oxygen-poor blood to the lungs
Only the oxygen-rich blood is delivered to the tissues

11. Specialized Teeth Mammals eat many types of food
Mammals have specialized teeth that reflect the difference in their diets
Mammalian teeth are continually lost and replaced
Mammalians usually only have two sets of teeth
Baby Teeth = the first set
Permanent Teeth = the second set (not replaced)

12. Types of Teeth Most mammalians have four types of teeth
Each type of tooth performs a different function
Incisors - Biting and cutting (Front teeth)
Canines - Used for stabbing and holding (behind incisors)
Premolars – Crushing and grinding (line the jaw)
Molars- Crushing and grinding (line the jaw)

14. Types of Teeth Teeth of herbivores: Teeth of carnivores:
Small incisor- shaped canines
Incisors and canines used to nip off pieces of plant material
Premolars and molars are flat and covered with ridges to create a surface where plants can be ground
Teeth of carnivores:
Long canine teeth that are suited for grasping prey
Sharp molars and premolars can cut off pieces of flesh

15. Parental Care
Young mammals depend on their mother for a relatively long period of time
They receive milk and other food
Milk is produced in the mammary glands, which are located on the female’s chest or abdomen
Protection
shelter

16. Parental Care All mammals reproduce by internal fertilization
Mammals differ in how and where their fertilized eggs develop
Mammals are classified into three groups based on their pattern of development
Monotremes
Marsupials
Placental Mammals

17. Monotremes Monotremes are oviparous = reproduce by laying eggs
Eggs hatch quickly, and the mother stays with and nurses the young for several months
There are only two alive today:
Duckbill platypus & echidnas

18. Marsupials
After fertilization, marsupial embryos remain inside their mother for only a few days or weeks
The young crawl out of the mother, up the fur on her belly, and to her nipples, which are usually located inside a pouch
Completes development inside its mother’s pouch

19. Placental Mammals
Placental Mammals complete their development inside the mother
The placenta attaches the fetus of the mother and allows exchange of oxygen, nutrients, and wastes
the period of time between fertilization and birth is called the gestation period

20. Movement
Mammals use various modes of locomotion, including running, hopping, climbing, flying, burrowing, and swimming
Adaptations in body structure help mammals move around in their particular environments

21. Response
Mammals rely on their senses- vision, hearing, smell, taste, and touch- for survival
The importance of a given sense depends on the animal’s lifestyle
Example:
Bats and Dolphins live in different locations but both use echolocation
Echolocation is the process of using reflected sound waves to find objects

22. Answer the following… What are three functions of hair?
Why does a mammal need to eat more food than a reptile of similar size?
What type of tooth is used for stabbing a holding ?
What group of mammals lay eggs?
What are three types of locomotion that mammals use?