讲一讲How dinosaurs became birds,参考以下文本，生成一个英文讲解视频：over 66 million years ago, unfamiliar
animals dominated the Earth, some
growing to impressive heights of
over 30 metres. The dinosaurs
were captivating creatures, in part due to their
size, power and strength. When you observe a
robin gracefully flittering about your garden,
it seems unlikely that they could be related.
Palaeontologists are gathering information
about the dinosaurs with every new fossil
retrieved from the ground, and as more
species are discovered, it becomes
more apparent how diverse the
dinosaurs were. All modern birds
descended from a group of theropod
dinosaurs called the maniraptoran
theropods. These animals were
relatively small, ranging from
pigeon-sized to ten metres tall.
Crucially, dinosaurs evolved into modern
birds before the Cretaceous-Paleogene mass
extinction event that wiped out the dinosaurs
66 million years ago. The earliest modern birds
lived alongside the dinosaurs, and it was this
less significant group of animals that outlived
their mighty relatives.
One of the key evolutionary stages to the
survival of some dinosaurs was when theylearned to fly. This happened around 150
million years ago in the Jurassic period. The
two main theories of how dinosaurs took to
the air are the ‘ground-up’ theory and the
‘trees-down’ theory. The ground-up theory
states that fast, ground-dwelling theropod
dinosaurs with feathered arms flapped their
wings while running at high speeds in order
to lift themselves up into the air. Alternatively,
the trees-down theory is that tree-dwelling
dinosaurs used their wings for gliding.
While they couldn’t remain airborne
for long periods, they could return
to the ground and soar through
the trees.
From grounded predators
to gliding creatures, the evolution
of these beasts meant that when
most dinosaurs were wiped from
the Earth, others were able to live on,
becoming masters of the skies and bringing
dinosaur traits into the modern world. The age
of the dinosaurs didn’t entirely come to an end.
If you look closely enough, today you can hear
their ancestral cry in the caw of a crow, see the
same three-toed footprints as birds retrace
the paths of ancient giants and observe a
prehistoric hunting pose in the heron.
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Over 66 million years ago, unfamiliar animals dominated the Earth, some growing to impressive heights of over 30 metres. The dinosaurs were captivating creatures, in part due to their size, power and strength. When you observe a robin gracefully flittering about your garden, it seems unlikely that they could be related. Palaeontologists are gathering information about the dinosaurs with every new fossil retrieved from the ground, and as more species are discovered, it becomes more apparent how diverse the dinosaurs were.
All modern birds descended from a group of theropod dinosaurs called the maniraptoran theropods. These animals were relatively small, ranging from pigeon-sized to ten metres tall. Crucially, dinosaurs evolved into modern birds before the Cretaceous-Paleogene mass extinction event that wiped out the dinosaurs 66 million years ago. The earliest modern birds lived alongside the dinosaurs, and it was this less significant group of animals that outlived their mighty relatives.
This happened around 150 million years ago in the Jurassic period. Crucially, dinosaurs evolved into modern birds before the Cretaceous-Paleogene mass extinction event that wiped out the dinosaurs 66 million years ago. The earliest modern birds lived alongside the dinosaurs, and it was this less significant group of animals that outlived their mighty relatives.
One of the key evolutionary stages to the survival of some dinosaurs was when they learned to fly. This happened around 150 million years ago in the Jurassic period. The two main theories of how dinosaurs took to the air are the ground-up theory and the trees-down theory. The ground-up theory states that fast, ground-dwelling theropod dinosaurs with feathered arms flapped their wings while running at high speeds in order to lift themselves up into the air. Alternatively, the trees-down theory is that tree-dwelling dinosaurs used their wings for gliding.
From grounded predators to gliding creatures, the evolution of these beasts meant that when most dinosaurs were wiped from the Earth, others were able to live on, becoming masters of the skies and bringing dinosaur traits into the modern world. The age of the dinosaurs didn't entirely come to an end. If you look closely enough, today you can hear their ancestral cry in the caw of a crow, see the same three-toed footprints as birds retrace the paths of ancient giants and observe a prehistoric hunting pose in the heron.