How birds fly and why some cant
their bones are hollow
they a curved shaped wing
they use the air flow like an river to fly
they have large lungs
they have strong wing mussles
they use the trust and lift
birds that cant fly use their wings for other things
even if the ansester of flightless birds could fly they cant
there are 60 living flightless birds
all pengin are flightless
lots of birds have evolved to live on land
birds that cant fly can survive on less nutrient land masses like grass plain whereas flying birds have to eat stuff like fruit
pengins uses their flight mussels to swim
if a bird stops felling that it needs to fly it stop and then adapts its wings shrink or can be lost compleatly and their bones get denser and non hollow. Also their feathers turn to fluff.
flight benifits
to easily get away from being eaten
flight losses
uses lots of energy
to hunt
to go long distances
limits body size and weight
ostrich, emu and cassowary are giants compared to other flightless birds like kiwi .e.c.t.