Aves - Birds PDF

**Aves -- Birds** Learn Aves-General characters in 3 minutes. **Characteristic features:** 1. They maintain constant body temperature -- they are warmblooded, **endothermic**. 2. Their body is segmented, divided into a head, trunk and tail. 3. Their body is spindle shaped, streamlined wh...

**Aves -- Birds** Learn Aves-General characters in 3 minutes. **Characteristic features:** 1. They maintain constant body temperature -- they are warmblooded, **endothermic**. 2. Their body is segmented, divided into a head, trunk and tail. 3. Their body is spindle shaped, streamlined which help them to fly. 4. The forelimbs are modified into **wings**. 5. Their hindlimbs have **claws** and are adapted to perching, walking, wading and some for swimming. 6. The body is covered with **feathers.** Skin is **dry** with no glands except the uropygial gland ( oil gland) near their tail for preening. 7. The jaw is modified into a **horny beak** with no teeth. They can pick and hold things in their beak. 8. They have **hollow bones** filled with air. They are called pneumatic. 9. They have an amniotic egg with shell. Aves -- general characteristics -- video: [[https://youtu.be/A\_enCZvQrcU]](https://youtu.be/A_enCZvQrcU)  The shape of a beak shows its function Bird feet \| Bird drawings, Bird artwork, Animal drawings Different types of claws according to different function **Evolution of Birds** The discovery that birds **evolved from small carnivorous dinosaurs** of the Late Jurassic was made possible by recently discovered fossils from China, South America, and other countries, as well as by looking at old museum specimens from new perspectives and with new methods. The hunt for the ancestors of living birds began with a specimen of **Archaeopteryx**, the first known bird, discovered in the early **1860s.** Like birds, it had **feathers** along its arms and tail, but unlike living birds, it also **had teeth** and a **long bony tail**. Furthermore, many of the bones in Archaeopteryx\'s hands, shoulder girdles, pelvis, and feet were distinct, not fused and reduced as they are in living birds. Based on these characteristics, **Archaeopteryx was recognized as an intermediate between birds and reptiles**.  Archaeopteryx In the 1970s, paleontologists noticed that *Archaeopteryx* shared unique features with small carnivorous dinosaurs called theropods. Based on their shared features, scientists reasoned that perhaps the theropods were the ancestors of birds. The birds are simply a twig on the dinosaurs\' branch of the tree of life. As birds evolved from these theropod dinosaurs, many of their features were modified. Small theropods probably evolved the first feathers. These short, hair-like feathers grew on their **heads, necks, and bodies** and provided insulation. The feathers seem to have had different color patterns as well, although whether these were for **display**, **camouflage, species recognition**, or another function is difficult to say. **Body structure**  **Skeleton** Birds \| Veterian Key  -- -- A bird\'s skeleton is similar to ours in some ways -- it has a skull and legs and other features humans have -- but it also has some important and very useful differences. For example, the total number of bones in a bird\'s body is lower than for mammals or reptiles. This is the advantage if a bird wants to take to the air. The bird skeleton is extremely lightweight, but strong enough to withstand the stresses that a bird experiences when taking off, flying, and landing. The bird\'s **hollow bones** make the skeleton lighter for flying, and allow more oxygen to be absorbed from the air into the blood. Bird bones usually contain air. Many bird bones are hollow, with cross walls that crisscross for structural strength. Some flightless birds -- like penguins -- have only **solid bones**. Bird **skull bones** have air cavities that are continuous with the nasal cavities. **Trunk bones** -- including the **vertebrae, breastbone and pelvic bones** -- also contain air sacs invading from the lungs. These are all called **pneumatic bones**. The number of hollow bones in a bird\'s body will vary from species to species, though large gliding and soaring birds tend to have the most. Birds have **more neck (cervical) vertebrae** (back bones) than many other animals. Most birds have **13 to 25** of these very flexible bones. Thanks to this bone structure, birds are better able groom their feathers. Birds are the only vertebrate animals to have a **fused collarbone** (the **furcula** or **wishbone**). They\'re also the only vertebrate animals to a have a **keeled breastbone (hrebeň)** -- a breastbone that\'s long and has a structure on it shaped like a ship\'s keel. A ship\'s keel runs from the front of a ship to the back and the ship\'s entire framework attaches to it. The keel part of a bird\'s breastbone extends outward from the top of the bone and down the breast area and acts as **an anchor for a bird\'s** **strong wing muscles**. The keel is a feature of strong flying or swimming birds. Most birds have only **four toes**. Some have **only three**. The **ostrich has just two** toes. Most perching birds have four toes, with three that point forward and one that points back. However a few groups -- including cuckoos, cockatoos and parrots, and owls, clutch the branch with two toes forward and two back.\ \ **Body systems:**  **Digestive system:** **beak**, mouth, tongue, pharynx, aesophagus, **crop** (to collect food and pre-digest it), two types of stomach -- **proventriculus** and **gizzard**, small, large intestines, **cloaca,** liver, pancreas, gall bladder, Internal Anatomy Digestive system of birds In many birds, the oesophagus ends in a specialised storage organ called the **crop**. This is basically just an enlarged part of the oesophagus... where food eaten in a hurry to avoid predators is stored until it can be digested later. The bird's stomach can be divided into two sections, the proventriculus and the gizzard. The **proventriculus**, sometimes called the **glandular stomach**, is a tube-like area which produces a large amount of **digestive juices** -- particularly enzymes such as **pepsin and hydrochloric acid.** It also serves as an additional storage area in some birds, such as gulls, and produces a defensive smelly oil in the Fulmar (*Fulmarus glacialis*) -- which can be ejected through the mouth and open bill at an approaching predator. **Once the food has been well soaked in digestive fluids it passes into the bird's gizzard.** The gizzard is a **highly muscular organ**, which performs the same role in birds that jaws and teeth perform for us. In other words it grinds the food up into small pieces, increasing its surface area and enabling it to be more easily digested. Some species of birds -- particularly those which feed on hard dry seeds -- will also eat **small pebbles**. These become lodged in the bird's gizzard and help grind up the food. Evolution of digestive system and birds video: [[https://youtu.be/jaR2d0FM28Y]](https://youtu.be/jaR2d0FM28Y) **Breathing system:** Birds need more oxygen than other Vertebrata because of flying. Volume of their lungs is small, therefore they have additional **air sacs** which raises the volume of the Respiratory system. **Trachea** divides into **primary bronchi** each of which passes through a lung and then to the paired abdominal air sacs; they also give rise to **secondary bronchi** supplying the other air sacs. **Tertiary bronchi** penetrate the lung mass and, from the walls of the tertiary bronchi, air capillaries arise. These air capillaries have a large surface area; their walls contain blood capillaries connected with the heart. Gas exchange takes place between the air capillaries and blood capillaries, making this surface analogous to the alveolar surface in mammals. The respiratory system of birds is also used for communication through [song](https://www.britannica.com/science/birdsong-animal-communication). The "voice box" is the **syrinx**, a membranous structure at the lower end of the trachea. Sound is produced only when air flows outward across the syrinx. In canaries, notes or pulses are synchronous with chest movements; the trills, however, are made with a series of shallow breaths. The song of many small birds is of long duration relative to their breathing frequencies.  Výsledok vyhľadávania obrázkov pre dopyt Breathing system of birds **Respiration in birds video: [[https://youtu.be/7mlr\_fpQvkg]](https://youtu.be/7mlr_fpQvkg)** **Circulatory system:** they have four chambered heart with two atria and two ventricles, double circulation -pulmonary and body. Their blood is not mixed as in amphibians and reptiles. They have higher average body temperature than mammals (41´C).  Výsledok vyhľadávania obrázkov pre dopyt Circulatory system of birds **Excretory system**: They have **two kidneys** for excretion of liquid waste**.** The kidneys in birds are considerable larger than those of humans. They have three lobes, the cranial (top), middle, and caudal (bottom), however they lack a defined cortex, medulla, and renal pelvis. Within the kidney it is divided into different lobules. Each lobules have an outer area and medullary cone. The ureter leads from each kidney to cloaca. The kidneys are metanephric which drain the nitrogenous waste matter (chiefly **uric acid)** into cloaca through the **ureters.** **Urinary bladder is absent** except **Rhea Americana** (American Rhea--- also called "South American Ostrich". **This is the only bird that has urinary bladder**). (Nandu pampový) Birds have a chamber called a **cloaca** where digestive wastes, uric acid, and eggs or sperm go before leaving the body. While the uric acid is in the cloaca, birds can reabsorb some of the water back. \... Some sea birds can drink sea water and excrete the extra salt out of **glands near their eyes**.  **Nervous system:** Brain is better developed than that of reptiles, of which **cerebrum, cerebellum** and **optic lobes** are quite large. Birds have **12 pairs of cranial nerves**. They have a good navigation system because of the devepoped front brain (cerebrum).  **Senses:** Birds have good developed a **sense of sight** but poor sense of smell but kiwi has good sense of smell. Pecten is present in the eyes of birds. **Ear openings** are present. Each ear consists of three parts: **external, middle and internal**. In general, they have 5 senses. **Reproductory system:** Birds do actually pair up each mating season, if not for life. And the male should be prepared to treat his female properly. There is actually an elaborate process in which the female chooses her mate. [Reproduction](https://www.ck12.org/c/life-science/reproduction?referrer=crossref) in birds may be quite complicated and lengthy. Birds reproduce **sexually** and have **separate sexes, sexual dimorphism is present** and **internal fertilization**, so males and females must mate for fertilization to occur. Mating is generally preceded by courtship. In most species, parents also take care of their eggs and hatchlings. Female has usually **well developed single left ovary and oviduct**. If right ovary and oviduct are present, they are vestigial (nonfunctional). They are oviparous with an amniotic egg with four embryonic structures (e.g., chorion, amnion, allantois and yolk sac). **[Courtship](https://www.ck12.org/c/biology/courtship?referrer=crossref) and Mating** **Courtship** is behavior that is intended to attract a mate. It may involve singing specific courtship songs or putting on some type of visual display. For example, a bird may spread out and display its tail feathers or do a ritualized mating "dance." Typically, males perform the courtship behavior, and females choose a mate from among competing males. Výsledok vyhľadávania obrázkov pre dopyt Reproduction of birds  Different methods of bird courtship During mating, a male bird presses his **cloaca** against his mate's cloaca and passes sperm from his cloaca to hers. After fertilization, eggs pass out of the female's body, exiting through the opening in the cloaca. **Nesting and Incubation** Eggs are usually laid in a nest. The nest may be little more than a small depression in the ground, or it may be very elaborate, like the weaver bird nest in [below](https://flexbooks.ck12.org/cbook/ck-12-biology-flexbook-2.0/section/12.20/primary/lesson/bird-reproduction-bio#x-ck12-QmlvLTE5LTI5LWJpcmQtbmVzdHM.). Eggs that are laid on the ground may be camouflaged to look like their surroundings (also shown [below](https://flexbooks.ck12.org/cbook/ck-12-biology-flexbook-2.0/section/12.20/primary/lesson/bird-reproduction-bio#x-ck12-QmlvLTE5LTI5LWJpcmQtbmVzdHM.)). Otherwise, eggs are usually white or pastel colors such as pale blue or pink. Variation in bird nests Variation in Bird Nests. A weaver bird uses grasses to weave an elaborate nest (left). The eggs of a ground-nesting gull are camouflaged to blend in with the nesting materials (right). After birds lay their eggs, they generally keep the eggs warm with their body heat while the embryos inside continue to develop. This is called **incubation,** or **brooding**. In most species, parents stay together for at least the length of the breeding season. In some species, they stay together for life. By staying together, the males as well as females can incubate the eggs and later care for the **hatchlings**. Birds are the **only nonhuman** **vertebrates with this level of male parental involvement.** According to parental involvment after hatching we can distinguish two types of offspring: N**idicolous** **birds** - from Latin *nidus* \"nest\" and *-colus* \"inhabiting\") is an animal that **stays at its birthplace for a long time** because they depend on the parents for food, protection, and the learning of survival skills. They are born blind, without feathers, helpless (example sparrow). They are the opposite of **[nidifugous] species,** which leave their parents more quickly and survive independently (example duck).  Differences between nidiculous and nidifugous birds The birds are the most beautiful among the animals. They show courtship, nest building, parental care, migration and territorial behaviour. **Hatchlings** Nest of a marsh warbler with baby birds Aves -- reproduction video: [[https://youtu.be/jkk4rbfTAd0]](https://youtu.be/jkk4rbfTAd0) **Feathers:**  Different types of feathers in birds Výsledok vyhľadávania obrázkov pre dopyt Feathers - structure Different types and parts of feathers A structure of a feather **The structure of feathers:** At a microscopic level, **feathers** are **made of** a protein called **beta-keratin**. The same protein also forms the **beaks** and **claws** of birds, and the **scales** and **shells** of reptiles. It\'s close (but less rigid) relative, **alpha-keratin**, makes up the **nails**, **claws** and **hairs** of mammals. The typical **feather** consists of a central **shaft** (rachis), with serial paired branches (**barbs**) forming a flattened, usually curved surface---the **vane**. The barbs possess further branches ---the **barbules**---and the barbules of adjacent barbs are attached to one another by **hooks**, stiffening the vane. **Parts of a feather:** - Vane. - Rachis. - Barb. - Afterfeather. (aftershaft) - Hollow shaft, calamus.  Výsledok vyhľadávania obrázkov pre dopyt Feathers - structure Composition of a feather **Types of feathers:** The **feathers** we are used to see are flight and contour. **Down** **feathers** are what we use in pillows, quilts, and jackets. The other three feathers, **semiplume**, **filoplume**, and **bristle**, are not as common, but still useful to **birds**. **Contour feathers** give shape and color to the bird.  Different types of feathers How the feathers grow video: [https://youtu.be/P7JMdO1mQZw] **Classification of Aves** [[https://www.slideshare.net/HabiburRahman37/classification-of-aves]](https://www.slideshare.net/HabiburRahman37/classification-of-aves) There are about 10,000 living species of birds. Almost all of them can fly, but there are several exceptions. **Flightless Birds** Some birds have lost the ability to fly during the course of their evolution. Several flightless birds are shown  [below](https://flexbooks.ck12.org/cbook/ck-12-biology-flexbook-2.0/section/12.21/primary/lesson/bird-classification-bio#x-ck12-QmlvLTE5LTMwLWZsaWdodGxlc3MtYmlyZHM.). They include the **ostrich, kiwi, rhea, cassowary**, and **moa**. All of these birds have long legs and are adapted for running. The **penguins** shown in the figure are also flightless birds, but they have a very different body shape. That's because they are adapted for swimming rather than running. Various flightless birds Flightless Birds. Flightless birds that are adapted for running include the ostrich, kiwi, rhea, cassowary, and moa. Penguins are flightless birds adapted for swimming. **Flying Birds** Birds that are able to fly are divided into 29 orders that differ in their physical traits and behaviors. The table [below](https://flexbooks.ck12.org/cbook/ck-12-biology-flexbook-2.0/section/12.21/primary/lesson/bird-classification-bio#x-ck12-dGFibGU6YmlyZHM.) describes seven of the most common orders. As shown in the table, the majority of flying birds are **perching birds**, like the honeyeater described in the last row of the table. The order of perching birds has more species than all the other bird orders combined. In fact, this order of birds is the largest single order of land vertebrates. +-----------------------+-----------------------+-----------------------+ | **Order** | **Description** | **Example** | +=======================+=======================+=======================+ | Landfowl: turkeys, | They are large in | turkey | | chickens, pheasants | size; they spend most | | | | of their time on the |  | | | | | | | they usually have a | | | | **thick neck and | | | | short**, rounded | | | | wings; their flight | | | | | | | | tends to be brief and | | | | close to the ground. | | +-----------------------+-----------------------+-----------------------+ | Waterfowl: ducks, | They are large in | ducks | | geese, swans | size; they spend most | | | | of their time on | | | | the water | | | | | | | | surface; they **have | | | | webbed feet** and are | | | | **good swimmers**; | | | | most are | | | | | | | | strong flyers. | | +-----------------------+-----------------------+-----------------------+ | Shorebirds: puffins, | They range from small | puffin | | gulls, plovers | to large; most live | | | | near the water, and |  | | | | | | | are sea birds; they | | | | **have webbed feet** | | | | and are **good | | | | swimmers**; most | | | | | | | | are strong flyers. | | +-----------------------+-----------------------+-----------------------+ | Diurnal Raptors: | They range from small | hawk | | hawks, falcons, | to large; they are | | | eagles | active during the day | | | | and sleep | | | | | | | | during the night; | | | | they have a **sharp, | | | | hooked beak** and | | | | **strong legs with** | | | | | | | | **clawed feet**; they | | | | hunt by sight and | | | | **have | | | | excellent vision**. | | +-----------------------+-----------------------+-----------------------+ | Nocturnal Raptors: | They range from small | burrowing owl | | burrowing owls, barn | to large; they are | | | owls, horned owls | **active during the |  | | | | | | | sleep during the day; | | | | they have **a sharp, | | | | hooked beak** and | | | | **strong legs** | | | | | | | | **with clawed feet**; | | | | they have **large, | | | | forward-facing eyes** | | | | ; | | | | they have | | | | | | | | **excellent hearing** | | | | and can hunt with | | | | their sense of | | | | hearing alone. | | +-----------------------+-----------------------+-----------------------+ | Parrots: cockatoos, | They range from small | cockatoo | | parrots, parakeets | to large; they are | | | | found | | | | **in tropical regions | | | | **; | | | | they | | | | | | | | have a strong, | | | | **curved bill**; they | | | | stand upright on | | | | strong legs with | | | | clawed | | | | | | | | feet; many are | | | | **brightly colored**; | | | | they are **very | | | | intelligent**. | | +-----------------------+-----------------------+-----------------------+ | Perching Birds: | They are **small in | honeyeater | | honeyeaters, | size**; they **perch | | | sparrows, crows | above the ground in |  | | | | | | | buildings and wires; | | | | they have **four | | | | toes** for grasping a | | | | perch; many | | | | | | | | are **songbirds.** | | +-----------------------+-----------------------+-----------------------+ Výsledok vyhľadávania obrázkov pre dopyt classification of aves