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rcornelio
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Describe the evolutionary history of birds
- Birds+ dinosaurs shared common ancestors
- the oldest known bird fossil was archaepteryx
- It had the following bird features : feathers and flight features
- But it was also reptile like because it had teeth and a very long tail with vertebrate modern birds don't have that
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Why did flight evolve?
- Air was an unexploited environment
- there were escape from terrestrial predators
- could travel faster in air
- allowed for migration
- abundance of prey due to flying insects
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Give the three theories of the evolution of flight and which one is the most preferred?
- Ground up : birds gradually developed wings from leaping up to grab prey
- Trees down : evolved from gliding structures which they began to flap in order to produce thrust
- Sexual selection: wings were used to as a form of display for courtship
- Ground up is the most preferred
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Why are birds not easily fossilized
They have delicate bones
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A large flightless bird
related to geese
occurred in Australia 15 mya
Dromornis stironi
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What are common characteristics shared by all birds?
- Feathers and wings (although not all can fly)
- Beak (without teeth)
- They lay hard shelled eggs
- They have light but tensile bones
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Largest bird in OZ
Smallest bird in OZ
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Give me the five types of Australian Birds
- Long established non passerines with gondwanan distribution
- Corvid passerines
- Recent paserines colonists from eurasia
- Introduced species
- international birds
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Describe Long established Passerines
- Three groups : ratites , parrots and penguins
- Ratites : large flightless birds emu ostriches and cassowaries are examples
- Parrots : two families cockatoos and parrots
- have short strong claws that can manipulate food , no sexual dimorphism are long lived , rely in tree hollows to nest and intelligent
- they can live in rainforest ,woodlandand arid zones
- some have broad distribution (sulfur crested cockatoo)
- others very restricted
- cockatoos are crested
- are threatened due to habitat loss and fragmentation
- Penguins: generally found in cold habitats
- must reproduce on land and hunt in sea
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Describe corvid passerines
- More than 50% of Australian species
- diverse group descended from crows
- i.e magpies , fairywrens and blue faced honey eaters
- the last very important for pollination
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Describe recently colonized eurasian passerines
- these are still considered native but they recently colonized here and now breed in Aus
- low diversity due to short history in Oz
- i.e wedge tailed eagl,song thrush . welcome swallow
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Introduced species
- Pests
- indroduced by humans
- house sparrow ,indian mynah
- they succeed as they are good invaders , wide tolerance good reproduction , eat anything
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World wide groups
- Come in two - raptors
- -sea birds
- Raptors : kites and falcons
- sea birds migrate here to escape winter in the north
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