Birds

• what did birds evolve from?

  land living dinosaurs
• how do we know that birds did not evolve from pterodactyls?

  they became extinct
• what are birds most closely related to?

  crocodiles and other reptiles rather than mammals
• what is the link between birds and the dinosaurs?

  the archaeopteryx fossil
• why were flightless birds able to evolve?

  reduce predation risk at the time
• what does plumage allow birds to do?

  display it to attract a male or use it as camouflage to avoid predation
• what does precocial mean?

  advanced young which come out of the egg with feathers, able to thermoregulate themselves and feed themselves
• why is being in a social flock better for safety?

  dilution effect (if a predator comes in, it is less likely to be you taken) and more eyes and ears to look out for predators
• what is the defining feature of a bird?

  feathers
• what did feathers evolve from?

  scales on the skin
• why are feathers so important?

  provide insulation, colour allows adaptations through sexual and natural selection and they enable flight
• did feathers evolve from flight?

  no - flight is a secondary adaptation from the presence of feathers
• what are the main body feathers on birds called?

  contour feathers
• what are the feathers beneath the counter feathers in ducks called?

  down feathers
• what are the structural feathers between contour feathers called?

  semiplumes
• how many times has active, flapping fight evolved?

  four times
• what are the three main physical traits required for flight?

  large wing surface, high energy to provide energy to the large muscles needed for the powerful lift off and very efficient oxygen transport to the muscles
• what is the wing aspect ratio?

  the wingspan squared divided by the wing area
• what does a low wing aspect ratio see?

  short and round wings
• what does a high wing aspect ratio see?

  long and thin wings
• what do wing tip slots allow for?

  greater control at lower speeds
• who are wing tip slots seen in?

  large birds who soar a lot such as cranes, eagles, vultures and buzzards
• what is the air flow like in birds lungs?

  one way
• are the air pump and gas exchange systems together or separate in birds?

  separate
• what does the air pump and gas exchange system being separate in birds mean for the gas exchange membrane?

  it can be thinner so birds can remove an extra 25 % more oxygen per breathe
• what are two other adaptations that birds have for flight?

  hallow bones and no teeth
• how are hallow bones an adaptation for flight?

  lighter in weight
• how is having no teeth an adaptation for flight?

  teeth are heavy and will offset the centre of gravity
• where do birds chew and grind up their food?

  in their digestive systems in a sac called a gizzard