Birds Mammals Chapter 16 Section 1 Birds v

Birds & Mammals Chapter 16

Section 1 Birds v. Birds belong to the class Aves. v. Aves comes from the Latin word for bird. v. First appeared on Earth 150 million years ago

Section 1 Bird Characteristics v. Share some characteristics with reptiles • Thought to be descendent from dinosaurs • Legs & feet covered by thick, dry scales • The skin around their beaks scaly • Have amniotic eggs – with an amniotic sac & a shell ü but bird shells are generally harder than reptiles which are usually leathery v. Beaks instead of teeth & jaws v. Have feathers, wings, & many other adaptations for flight

Section 1 Bird Characteristics: Cont. Birds of a Feather v Two kinds of feathers • Down Feathers = fluffy, insulating feathers that lie next to a bird’s body. • Contour Feathers = cover the body & wings of birds to form a streamlined flying surface v. Preening = a process where birds use their beaks to spread oil on their feathers (The oil helps make the feathers water repellent & keeps them clean)

Section 1 Bird Characteristics: Cont. High-Energy Animals v Birds are endothermic – they maintain a constant body temperature • Have a high metabolism which generates a lot of body heat • Average body heat of bird is 40 o. C higher than a humans • Birds can’t sweat if they get too hot so they pant like dogs do.

Section 1 Bird Characteristics: Cont. Eat Like a Bird? v Most birds eat a high-protein, high-fat diet of insects, nuts, seeds, leaves, or meat. v Don’t v Food have teeth, so they can’t chew their food. goes directly from the mouth to the crop, where it is stored. Birds also have an organ called a gizzard, which often contains small stones. The stones in the gizzard grind up the food so that it can be easily digested by the intestine.

Section 1 Up, & Away Birds have a long list of adaptations for flight even those that are flightless. v. Most birds have large eyes & excellent eyesight. • This allows them to see objects & food from a distance. v. The heart of a bird beats rapidly. • This ensures that the flight muscles get as much oxygen as the blood can carry.

Section 1 Up, & Away: Cont. v. Birds have special organs called air sacs attached to their lungs. • The air sacs increase the amount of oxygen that a bird can take in & allow air to flow constantly in one direction through the lungs. v. The shape of a bird’s wings is related to the kind of flying it does. • Short, rounded wings allow rapid maneuvers. Long narrow wings are best for soaring.

Section 1 Up, & Away: Cont. v. Bird skeletons are compact & strong. • Some of the vertebrae, ribs, & hip bones are fused together. This makes the skeleton of birds more rigid than that of other vertebrates. v. Bone is a heavy material, but birds have much lighter skeletons than those of other vertebrates because their bones are hollow. • But bird bones are still very strong because they have thin cross-supports that provide strength, much like the trusses of a bridge do.

Section 1 Up, & Away: Cont. v. Birds that fly have powerful flight muscles attached to a large breastbone called a keel. These muscles move the wings. v. All of the previous adaptations make a bird well suited for flight, but how do birds actually overcome gravity & get into the air?

Section 1 Getting Off the Ground v Lift = the upward pressure on the wing that keeps a bird in the air. • The air on top has to move farther than the air underneath. As a result, the air on top moves faster than the air underneath. The faster moving air on top creates low pressure in the air. This is called Bernoulli effect. The air pressure under the wing is higher & pushes the wing up. v Birds generate extra lift by flapping their wings. v Another factor that affects lift is wing size.

Section 1 Fly Away v Birds have good reasons to migrate & are able to migrate great distances. • They can find better territories with more food. • Great places for birds to raise their young.

Section 1 Bring Up Baby v Birds reproduce by internal fertilization & by laying amniotic eggs with the developing embryo inside just like reptiles. • But they must keep their eggs warm for the embryo to develop. ü Brooding = birds sit on their eggs until the eggs hatch, using their body heat to keep the eggs warm

Section 1 Bring Up Baby: Cont. Ready to Go v Precocial = birds that hatch fully active • Covered with downy feathers when born • Follow their parents as soon as they can stand up • Depend on their mother for warmth & protection • Can walk, swim, & feed themselves

Section 1 Bring Up Baby: Cont. Help Wanted v Altrical = birds hatch weak, naked, & helpless • Eyes are closed when they are born • Cannot walk or fly • Parents must keep them warm & feed them for several weeks. • When the chicks grow their first flight feathers they begin to learn to fly • Often end up walking around on the ground. The parents must work feverishly to distract predators & protect their young

Section 1 Kinds of Birds v There almost 9, 000 species of birds on the Earth, because of the diversity they are divided into 29 different orders. • This can be confusing so they are usually divided into four nonscientific categories: flightless birds, water birds, birds of prey, & perching birds. ü Not all birds are included in these categories but they dhow different birds can be

Section 1 Kinds of Birds: Cont. v. Flightless Birds – ostriches, kiwis, emus, ostriches, & other flightless birds do not have a large keel for flight. Though they cannot fly, many flightless birds are fast runners. v. Water Birds – sometimes called waterfowl. These include cranes, ducks, geese, swans, pelicans, loons, & other species. These birds usually have webbed feet for swimming, but they are also strong flyers.

Section 1 Kinds of Birds: Cont. v. Birds of Prey – eagles, hawks, falcons, & other birds of prey are meat eaters. The sharp claws on their feet & their sharp, curved beaks help these birds catch & eat their prey. They also have very good vision. Most birds of prey hunt during the day. v. Perching Birds – songbirds, like robins, wrens, warblers, & sparrows, are perching birds. These birds have special adaptations for perching on a branch. When a perching bird lands on a branch, its feet automatically close around the branch. So even if the bird falls asleep, it will not fall off.

Section 1 Birds Review 1. List three ways birds are similar to reptiles & three ways they are different 2. Explain the difference between precocial chicks & altricial chicks 3. Name some of the adaptations that make bird bodies lightweight. 4. Would an airplane wing that is not curved on top generate lift? 5. How did perching birds get their name? 6. Birds of prey have extremely good eyesight. Why is good vision important for these birds?

Section 2 Mammals v 4, 500 species of mammals v. Live in the coldest oceans to the hottest desert & every climate in between The origin of Mammals v. Therapsides = the early ancestor of mammals (they lived about 280 million years ago) v 200 million years ago mammals were about the size of mice, because they were endotherms they could hunt at night & avoid their dinosaur predators.

Section 2 Characteristics of Mammals Mamma! v. All mammals have mammary glands. • Mammary Glands = secrete a nutritious fluid called milk. v. Only mature female mammals make milk, male mammals have small inactive mammary glands v. Female mammals usually bear live young & care for their offspring v. All milk is made of water, protein, fat, & sugar.

Section 2 Characteristics of Mammals: Cont. Cozy & Warm v All mammals are endotherms v Body temperature kept constant except when hibernating, estivating, or running a fever. Staying Warm v All mammals have hair somewhere on their body. v Most mammals have a layer of fat under their skin that acts as insulation.

Section 2 Characteristics of Mammals: Cont. Crunch! v. Have specialized teeth • Canines – stabbing teeth, shaped like spears • Incisors – cutting teeth, in front of your mouth • Molars – flat teeth, that help grind up food v. The kinds of teeth a mammal have reflect its diet v. Have two sets of teeth • Milk teeth – a mammal’s first set of teeth • Permanent adult teeth – begins eating solid food & its jaw grows larger

Section 2 Characteristics of Mammals: Cont. Getting Oxygen v. Mammals need oxygen to efficiently break down the food they eat. v. Mammals use lungs to get oxygen from the air v. Diaphragm = a large muscle that lies at the bottom of the rib cage which helps bring air into the lungs. v. Have a four chambered heart – keeps blood with oxygen separate from blood without oxygen.

Section 2 Characteristics of Mammals: Cont. Large Brains v. Allows them to learn, move, & think quickly v. Keep track of what is going on & to respond quickly v. Most coordinated of all animals v. Depend on five major senses to gather information about their environment: vision, hearing, smell, touch, & taste. v. The importance of each sense for any give mammal depends on the mammals environment

Section 2 Characteristics of Mammals: Cont. Mammal Parents v. Reproduce v. Most v. All by internal fertilization mammals give birth to live young mammals nurse their young v. Born helpless & they require a lot of care v. Mammal parents are very protective, with one or both parents caring for their young until they are grown.

Section 2 Kinds of Mammals v. Mammals are divided into three groups based on the way their young develop Monotremes v. Monotremes = mammals that lay eggs v. Only found in Australia & New Guinea v. Only three species today: two are echidnas, the third is the duckbilled platypus v. Lays one or two eggs with thick, leathery shells v. Keep eggs warm like birds do v. Can’t nurse like other mammals, no nipple, instead the kind of sweat out the milk

Section 2 Kinds of Mammals: Cont. Marsupials v. Marsupials = mammals with pouches v. Give birth to live young that are not fully developed, they then travel to the pouch where they continue to develop, there are mammary glands in the pouch. v 280 species which include opossum, koalas, Tasmanian devils, & wallabies v. Found in Australia, New Guinea, & South America

Section 2 Kinds of Mammals: Cont. Placental Mammals v. Most mammals are placental mammals v. Placental Mammals = embryos stay inside the mother’s body & develop in a uterus v. Placenta = a special attachment from the embryo to the uterus of their mother. It supplies food & oxygen from the mother’s blood to the growing embryo & it removes wastes from the embryo v. Gestation period = the time during which an embryo develops within the mother

Section 2 Kinds of Placental Mammals v 90% or all mammals on Earth are placental mammals v. They are classified into 18 orders Toothless Mammals – anteaters, armadillos, aardvarks, pangolins, & sloths v. Although these mammals are called “toothless, ” only the anteaters are completely toothless. The others have small teeth. Most toothless mammals feed on insects they catch with their long sticky tongues.

Section 2 Kinds of Placental Mammals: Cont. Insect Eaters – moles, shrews, & hedgehogs. v. Insect eaters, or insectivores, live on every continent except Australia. Most insectivores are small, & most have long pointed noses to dig into the soil for food. Compared with other mammals, they have a very small brain & few specialized teeth. v. The first mammals on Earth looked much like today’s insectivores.

Section 2 Kinds of Placental Mammals: Cont. Rodents – squirrels, mice, rats, guides pigs, porcupines, & chinchillas v. More than one-third of all mammalian species are rodents, & they can be found on every continent except Antarctica. Most rodents are small animals with long, sensitive whiskers. Rodents are chewers & gnawers. All rodents have sharp front teeth for gnawing. Because rodents chew so much, their teeth wear down. So a rodent’s incisors grow continuously, just like your fingernails do.

Section 2 Kinds of Placental Mammals: Cont. Lagomorphs – Rabbits, hares, & pikas v. Like rodents, they have sharp gnawing teeth. But unlike rodents, they have two sets of incisors in their upper jaw & short tails. Rabbits & hares have long, powerful hind legs for jumping. To detect their many predators, they have sensitive nose & large ears & eyes.

Section 2 Kinds of Placental Mammals: Cont. Flying Mammals – Bats are the only mammals that can fly v. These mammals have wings made of long finger bones connected by webs of skin. Bats are active at night & sleep in sheltered areas during the day. When they rest, they hang upside down. Most bats eat insects. But some bats eat fruit, & three species of vampire bats drink the blood of other animals. The largest bats are the fruit bats, with a mass of up to 1 kg & wingspans up to 2 m. But most bats have a mass of only a few grams.

Section 2 Kinds of Placental Mammals: Cont. Carnivores – “meat eater” – lions, wolves, weasels, otters, bears, raccoons, & hyenas v. Carnivores are a group of mammals that have large canines & special teeth for slicing meat. Carnivores also include a group of fish-eating marine mammals called pinnipeds. The pinnipeds include seals, sea lions, & walruses. Some carnivores also eat plants. For example, black bears eat grass, nuts & berries & only rarely eat meat. But many carnivores eat nothing but other animals.

Section 2 Kinds of Placental Mammals: Cont. Hoofed Mammals – horses, zebras, pigs, cows, deer, hippopotamuses, & giraffes v. Most hoofed mammals are adapted for swift running. Because they are plant eaters, they have large, flat molars to help them grind plant material. Some also have modified digestive system that can handle large amounts of cellulose. Hoofed mammals are divided into groups based on the number of toes they have. Odd-toed hoofed mammals have one or three toes. Even-toed hoofed mammals have two or four toes.

Section 2 Kinds of Placental Mammals: Cont. Trunk-Nosed Mammals – Elephants are the only mammals with a trunk v. The trunk is an elongated & muscular combination of the upper lip & nose. Elephants use their trunk the same way we use our hands, lips, & nose. The trunk is powerful enough to lift a tree yet agile enough to pick small fruits one at a time. Elephants use their trunks to place food in their mouth & to spray their back with water to cool off. v. Elephants are the largest land animals.

Section 2 Kinds of Placental Mammals: Cont. Cetaceans – Whales, dolphins, & porpoises make up a group of water-dwelling mammals. v. At first glance whales & their relatives may look more like fish than mammals. But like all mammals, cetaceans are endotherms, they have lungs, & they nurse their young. Most of the largest wales are toothless whales that strain tiny, shrimplike animals form sea water. But dolphins, porpoises, sperm whales, & killer whales have teeth, which they use to eat fish & other animals.

Section 2 Kinds of Placental Mammals: Cont. Sirenia – three kinds of manatees & the dugong v. The smallest group of water-dwelling mammals. These mammals are completely aquatic; they live along coasts & in large rivers. They are quiet animals that eat seaweed & water plants.

Section 2 Kinds of Placental Mammals: Cont. Primates – prosimians, monkeys, apes, & humans v. There about 160 species of primates. All primates have the eyes facing forward, enabling both eyes to focus on a single point. Most have fingers on each hand & five toes on each foot, with flat fingernails instead of claws. Their fingers & opposable thumbs are able to make complicated movements, like grasping objects. They have a large brain in proportion to their body size & are considered some of the most intelligent mammals.

Section 2 Mammals Review 1. Name three characteristics that are unique to mammals 2. What is the purpose of a diaphragm? 3. Suppose you found a mammal skull on an archaeological dig. How would the teeth give you clues about the mammal’s diet? 4. How are monotremes different form all other mammals? How are the similar?