aves

• What class do birds belong to?

  Aves
• From which group did birds evolve?

  Dinosaurs
• What is a key characteristic of birds in terms of temperature regulation?

  They are endothermic
• What are the main features of bird body structure?


  • Aerodynamic body
  • Front limbs modified into wings
  • Bipedal locomotion
• What is the body covering of birds?


  Body covering: feathers, toothless beaked jaw

  flight, insulation, display, camouflage, signalling

  epidermal growths attached to the skin (pterylae)

  plumage is moulted
• What are the functions of feathers in birds?

  • Flight
  • Insulation
  • Display
  • Camouflage
  • Signalling
• What are pterylae in birds?

  Epidermal growths attached to the skin that are feathered areas - pterylae
• What is the body support structure of birds like?


  • Lightweight but strong
  • Ossified skeleton
  • Thin and hollow bones with pneumatic cavities
• What is the function of the crop in birds?

  It is used for storing food.
• What is the role of the gizzard in birds?

  It grinds food using stones.
• Why do birds have a high metabolic rate?

  It supports their energy needs for flight and other activities.
• What are some roles that bird beaks are adapted for?

  • Pecking
  • Grasping
  • Holding
  • Killing prey
  • Carrying
• Body support in : ossified skeleton (thin and hollow bones- pneumatic cavities), internal struts or trusses make them strong. Bones are fused together (smaller number). The last vertebrae

  form a synsacrum. More neck vertebrae (flexible ones)
• Digestive system: toothless beak, Crop for storing food, gizzard with stones for grinding food. High metabolic rate
• Feeding: Nidicolous (birds hatch helpless, featherless and underdeveloped; sparrow), Nidifugous (hatch well developed, leave nest immediately; chicken)
• Muscular system: adapted skeletal muscles. Developed breast muscles (flying species). Strong tendons in feet. Wings- depending on species (evolved from forelimbs). Not all birds fly
• Migration- Migratory (stork, swallow), Non-migratory (crow), Partially migratory (passerine species)
• What is the purpose of the keeled sternum?
• Respiratory system: 2 types of breathing (when relaxed or in flying mode). Syrinx- voice organ. The avian respiratory system affects thermoregulation. 9 air sacs.
• Circulatory system: highly efficient. Four chambered heart
• Exeretory system: paired metanephros (compare visual difference with opistonephros) Loop of Henle for the first time. Semi-solid urine. Nasal glands secrete salts. Cloaca. uropygial gland
• Nervous system: developed, coordinates flight, movement, behaviour, navigation, mating, mating, nest building.
• Sensory system: poor sense of smell. Highly developed vision and specialized light sensing cells. Mechanoreceptors
• Hormonal system: highly developed
• Reproduction in aves: common sexual dimorphism (colouring, size or vocalization). Males and females have a cloaca through which they pass eggs, sperm and waste. Females have one

  functional oviduct (adaption to reduce weight). With fertilization, the ovum becomes a developing embryo. This passes through the oviduct.