4. DINOSAUR HABITATS
Not all the dinosaurs lived at the same time. Nor did they all live in the same
part of the world. During the 180 million years that dinosaurs walked the Earth, the
break-up of the supercontinent Pangaea and the resulting major changes of
climate produced many different habitats. Continental drift (movement) changed
the world’s climate because it altered the flow of ocean currents and controlled
how much of the world was covered in ice. Different dinosaurs evolved to live in
different environments. Those that had existed on the dry Triassic supercontinent
were quite different from those that lived on the scattered landmasses of the
Cretaceous.
WHAT IS AN ECOSYSTEM?
An ecosystem includes all of the
living things (plants, animals and
organisms) in a given area, interacting
with each other, and also with their non-
living environments (weather, earth,
sun, soil, climate, atmosphere).
Ecosystems are the foundations of the
Biosphere and they determine the health
of the entire earth system.
6. DINOSAUR HABITATS
WHAT IS AN ECOSYSTEM?
WHAT ARE THE THREADS OF ECOSYSTEMS?
This very complex, wonderful interaction
of living things and their environment, has
been the foundations of energy flow and
recycle of carbon and nitrogen.
Anytime a ‘stranger’ (living thing(s) or external factor such as rise in
temperature) is introduced to an ecosystem, it can be disastrous to that
ecosystem. This is because the new organism (or factor) can distort the
natural balance of the interaction and potentially harm or destroy the
ecosystem.
Unfortunately, ecosystems have been disrupted, and even destroyed by
natural disasters such as fires, floods, storms and volcanic eruptions.
Human activities have also contributed to the disturbance of many ecosystems.
7. MESOZOICTRIASSIC
250-200MILLIONYEARSAGO
During the Triassic, all the landmasses of the world were
joined together, forming the single supercontinent, Pangaea.
Because the continent was so huge, most inland areas were a
long way from the ocean and there were extensive deserts.
Only around the edges of the continent was there enough
moisture for any vegetation. This was the time of the first
dinosaurs and they lived everywhere.
8. MESOZOICTRIASSIC
250-200MILLIONYEARSAGO
RIVERSIDES
Plant and animal life was most common
along the banks of rivers near the sea. The
river banks were covered with ferns and the
shallow water supported reed beds of
horsetails. Early carnivorous dinosaurs such
as Herrerasaurus hunted in these thickets.
SCRUBLAND
The semi-desert supported a scrubby
(low-growing vegetation) growth of plants
that could tolerate a lack of water. The
landscape must have looked rather like areas
of southern Africa do today. The drought-
resistant plants were browsed by early
herbivorous dinosaurs, such as the
prosauropod Plateosaurus.
9. MESOZOICJURASSIC
200-145MILLIONYEARSAGO
By the Jurassic, Pangaea had begun to break up. Rift
valleys produced long arms of ocean that reached into the
depths of the continent, very like today’s Red Sea in Egypt.
Shallow seas spread across the lowlands and reached into the
former deserts, giving rise to damper (slightly wet) climates in
most areas. There was much more vegetation than during the
Triassic, although the plants were the same types.
10. MESOZOICJURASSIC
200-145MILLIONYEARSAGO
RIPARIAN (RIVERLANDS) FOREST
As in the Triassic, the areas most covered
by vegetation were by the riversides.
Seasonal rainfall produced forests of tree
ferns and ginkgoes, with an undergrowth of
ferns and horsetails. These provided good
feeding for herbivorous dinosaurs such as
Stegosaurus.
DENSE CONIFEROUS FOREST
The forests were made up of primitive
conifers such as monkey puzzles,
cypresses, and podocarps (rare today),
as well as relatives of the cycads. The
tough needles on these evolved to guard
against the intensive high browsing of
sauropods such as Mamenchisaurus.
11. MESOZOICCRETACEOUS
145-65MILLIONYEARSAGO
By the Cretaceous, the continents had broken apart, many
of them beginning to look like the continents of today. The
presence of so many different land areas meant that the
climates were much more varied. The animal life was different
on each continent as each group of animals evolved
separately. So, for example, the dinosaurs of North America were
different from those of South America.
12. MESOZOICCRETACEOUS
145-65MILLIONYEARSAGO
SWAMPLAND (WETLANDS)
Swamps and river deltas are ideal places
for the preservation of fossils. Steamy swamps
existed along the edges of the Cretaceous
continents. Wet-loving trees such as swamp
cypresses dominated these areas. They provided
the perfect habitat for fish-eating dinosaurs such
as Spinosaurus.
MIXED FORESTS
By the Cretaceous, flowering plants
had begun to evolve. Dinosaurs with
efficient chewing mechanisms, such as
Corythosaurus, could both browse from
trees and graze close to the ground. This
led to the evolution of plants with seeds
that could survive this treatment.
13. MESOZOICCRETACEOUS
145-65MILLIONYEARSAGO
MOUNTAINS
Little is known about the vegetation of
mountain habitats because most fossils
come from lowland regions. But bones of
armoured dinosaurs, such as Edmontonia,
that look as though they have been washed
down from mountain areas, have been
found.
DESERT PLAINS
The deserts supported some
specialized animals. Although there was
little to eat, a large number of different
species of dinosaur lived in Cretaceous
desert sandstones. The open vistas
would have been ideal for long-legged
running dinosaurs such as Gallimimus.
15. MESOZOIC
TRIASSIC JURASSIC CRETACEOUS
• IT WAS HOT.
• IT HARDLY
RAINED.
• THERE WERE
EXTENSIVE
DESERTS.
• THERE WERE FEW
PLANTS (BUSHES).
• SMALL
DINOSAURS.
• IT WAS WARM.
• THERE WERE MORE
RIVERS AND SEAS
(CONTINENTS
BREAK-UP).
• THERE WERE MORE
FORESTS AND ALSO
DESERTS..
• THERE WERE MORE
PLANTS (BUSHES
AND TREES).
• GIANT
HERBIVOROUS
DINOSAURS (LONG-
NECKED).
• IT WAS HOT AND
RAINY.
• THERE WERE EVEN
MORE RIVERS AND
SEAS (CONTINENTS
BREAK-UP).
• THERE WERE MORE
MIXED FORESTS,
DESERTS,
WETLANDS,…
• THERE WERE EVEN
MORE PLANTS
(FLOWERS SHOWED
UP).
• BIG CARNIVOROUS
DINOSAURS.
16. DINOSAUR EXTINCTION
WHEN DID DINOSAURS BECOME EXTINCT?
WHY DID DINOSAURS DIE OUT?
Dinosaurs became extinct about 65
million years ago at the end of the
Cretaceous period. Then, Cenozoic era
begins. About 70% of all animal life on
earth died out. Scientists call it a mass
extinction – it wasn’t the first mass
extinction in earth’s history and it probably
won’t be the last!
There are many different theories about why
this happened. We will probably never know exactly
what happened, which means that scientists will
continue to disagree and come up with different
dinosaur extinction theories.
17. DINOSAUR EXTINCTION
WHY DID DINOSAURS DIE OUT?
ASTEROID IMPACT
A massive asteroid hit the earth at Chicxulub on the
Yucatan Peninsula in Mexico about 65 million years.
The meteor crater is 180 km from rim to rim and scientists
have worked out that the asteroid must have been 10 km
across. It is thought that the impact would have caused
massive damage, including a giant dust cloud which lead
to massive changes in the climate. This would have
destroyed lots of the cretaceous plants, so herbivorous
dinosaurs starved and the meat eating ones were left with
nothing to eat either.
ICE AGE THEORY
Now and again, the earth cools into periods we call ice ages.
As dinosaurs were thought to be cold blooded, it would have
been hard for them to cope with such cold conditions. For
example, if large parts of the planet were covered in ice, then
there would have been little or no plants for herbivorous
dinos to eat. However, there is no real evidence of an ice age
18. DINOSAUR EXTINCTION
WHY DID DINOSAURS DIE OUT?
VOLCANO THEORY
There was massive volcanic activity between
63 and 67 million years ago, particularly on the
Deccan Plateau in western India. This, again,
would have caused a massive change in climate,
which dinosaurs would have found hard to
adapt to.
DISEASE
It is possible that a disease spread
through the dinosaur population causing
their extinction.
19. DINOSAUR EXTINCTION
WHY DID DINOSAURS DIE OUT?
GRADUAL EXTINCTION
The number of dinos declined
throughout the cretaceous period.
Maybe a number of factors contributed
to their eventual extinction and they just
died out.
Dinosaur extinction is a big mystery,
as although dinosaurs died out at this time,
many species survived, including
similar animal types like crocodiles.
COMPETITION FROM OTHER ANIMALS
Fossils of small mammals have been
found from 65 million years ago. It is
possible that these small cretaceous
animals started to compete with
dinosaurs, for example stealing and eating
dinosaur eggs. However, no-one is sure
whether mammals caused dinosaur
extinction, or they thrived because dinosaurs
were no longer around. They would be
nocturnal rat-like mammals.
