A large meteor hit the earth
If a volcano erupts, the ash
from this blocks out the
sunlight and increases sulphur
dioxide and carbon dioxide in
the air
Some dinosaurs were eaten by
other species
Global warming caused the ice
caps to melt and there was a
flood
Reptiles lay eggs
Small mammals eat eggs
Pollution and radiation can
cause infertility
Sources of food became short
Some people think dinosaurs
were taken away by aliens to
another planet
Dinosaurs evolved into birds
Over 200 million years ago, the
continents were all joined
together (called Pangea)
Dinosaur fossils are found on
all the continents of the earth
Reptiles are cold-blooded and
need warmth to survive
Dinosaurs died out relatively
suddenly around 65 million
years ago
Mammals were becoming more Parts of dinosaur DNA are still
successful
seen in birds today
Dinosaur DNA is found in
mosquitoes trapped in amber
The elliptical orbit of the earth
changes slightly over long
periods of time, moving further
away from the sun
When volcanoes erupt, the ash Meteors can contain sources of
that is produced blocks out the radiation
light and heat from the sun.
Dust and soil from a meteor
collision has the same effect.
Radiation can cause cancer
Scientists can date some
materials using carbon dating
Mosquitoes can carry the
malaria parasite
When the continents moved
apart, the part with the
dinosaurs went to the North
Pole
Sulphur dioxide has been
linked to male infertility
250 million years ago 95% of
life disappeared
Increased pollution makes egg
shell thinner
Temperature of egg incubation
determines their success, and
the ratio of male to female
young dinosaurs
Large animals with high
metabolic rates need lots of
food
Many flowering plants produce
alkaloids which are toxic to
many herbivores
Flowering plants are very
efficient at producing oxygen
Increased levels of oxygen in
the air cause the rate of
metabolism in animals to
increase
Plants started to evolve to
produce flowers to aid
reproduction
Radiation can cause mental
disorders as a result of
changes to brain size
Solar flares and sunspots can
affect the climate and
atmosphere
Increased ultra-violet radiation
from solar flares can destroy
the ozone layer
High levels of radiation can
result in problems within egg
embryos
Lots of dinosaur bones have
been found trapped in lava
There were vast lava flows
found from 250 million years
ago in Siberia
Rock samples from the Karoo
Basin in South Africa do not
show signs of a meteor impact
A huge crater, 120 miles wide,
has been found in the gulf of
Mexico and dates back 65
million years
Fossil evidence shows that
most dinosaurs were extinct
long before 65 million years
ago