Mammals

 What You’ll Learn ·  You will identify the characteristics of mammals. ·  You will compare and contrast three groups of living mammals and examine their relationships to their ancient ancestors.    Section Preview  Objectives ·  Distinguish mammalian characteristics. ·  Explain how the characteristics of mammals enable them to adapt to most habitats on Earth.  Vocabulary ·  Metabolism: all of the chemical reactions that occur within an organism ·  Gland: a group of cells that secrete fluids. Different glands can produce saliva, sweat, oil, hormones, or milk. ·  Mammary Gland: modified sweat glands, which produce and secrete milk, a liquid that is rich in fats, sugars, and proteins. ·  Diaphragm: the sheet of muscle located beneath the lungs that separates the chest cavity from the abdominal cavity, where other organs are located.   <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Mini Lab 32 – Anatomy of a Tooth <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> 1. <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Examine a prepared longitudinal section view slide of a human tooth under low-power magnification. <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> 2. <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Locate the different areas – enamel, dentine, and pulp cavity – that form the tooth. Move the slide to see all areas. <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> 3. <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Diagram the tooth as it appears under low power. <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Answer the following Questions: <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> 1. <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Most of the tooth you studied is composed of the root under the gums. How is the part above the gum adapted to the diet of humans? <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Characteristics of Mammals <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Classification of Mammals <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Placental mammals- Placental mammals give birth to young that have developed inside the mother’s uterus until their body systems are fully functional and they can live independently of their mother’s body. Nourishment of the young inside the uterus occurs through an organ called the placenta. The placenta passes nutrients and oxygen to and removes wastes from the developing embryo. Development inside the mother is an adaptation that played a major role in the success of mammals. It ensures that the offspring are protected from predators during the early stages of development. <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Pouched mammals- Marsupials makeup the second subclass of mammals. It’s a mammal in which the young have a short period of development within the mother’s body, followed by a period of development inside a pouch made of skin and hair on the outside of the mother’s body. Ancestors of today’s marsupials were able to populate the landmass that became Australia without having to share the area with the competitive placental mammals that evolved in other places. <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Monotremes- A mammal that reproduces by laying eggs. <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Origins of Mammals <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> The first placental mammals appeared in the fossil record about 125 million years ago. Scientists trace the origins of placental mammals from a group of mouse-sized animals to a group of reptilian ancestors called Therapsids. Therapsids had features of both reptiles and mammals.
 * 1) <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Examine the diagrams of mammal skulls and predict what kinds of food these mammals might eat based on the shape of their teeth.
 * 1) <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Mammals have hair- Mammalian hair is made of protein keratin.
 * 2) <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Mammals nurse their young- Mammals have several types of glands, which are a group of cells that secret fluids. They include glands that produce saliva, sweat, oil, digestive enzymes, hormones, milk, and scent. Mammals also feed their young from **mammary glands** which produce and secret milk. Mammals nurse their young until their digestive systems are able to absorb nutrients from solid foods.
 * 1) <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Respiration and Circulation in mammals- Mammals need a high level of energy to maintain their endothermic metabolism. This energy is sustained when large amounts of nutrients and oxygen enter the body and reach the cells. The mammals’ **diaphragm** is the sheet of muscle located beneath the lungs that separates the chest cavity from the abdominal cavity, where other organs are located.
 * 2) <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Most mammals have specialized teeth- Mammals with teeth have different kinds that are adapted to the type of food they eat.
 * 1) <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Mammals have modified limbs- Mammals have several adaptations that help them meet their energy needs. For example, mammal limbs are adapted for a variety of methods of food gathering. Recall that primates use their opposable thumb to grasp objects- including fruits and other foods.
 * 2) <span style="font-family: 'Helvetica','sans-serif'; font-size: 12pt;"> Mammals can learn- One reason mammals are successful is that they guard their young fiercely and teach them survival skills.