Characteristics of Mammals

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 carnivores: • Long canine teeth that are suited for grasping prey • Sharp molars and premolars can cut off pieces of flesh • Teeth of herbivores: • 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

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?