Dinosaurs, they are still alive!
I think they are still among us.
but how can dinosaurs still be alive
when they were killed by an asteroid 66 million years ago?
Well it turns out it's actually not that simple.
While school books are quite happy with the story of an asteroid that killed all the dinosaurs
scientists are not.
There is still quite a debate going on what actually killed the dinosaurs.
The asteroid impact in Mexico did take place for sure.
Scientists were able to find the impact crater, it's called the chicxulub crater.
And we also find little pieces of molten rock and metals
all across the world that can be linked to this impact event.
Also asteroids carry a lot of iridium which is normally not found on the earth in high abundances.
And a spike of iridium concentration could be linked
with the disappearing of dinosaur fossils in the ground.
This peak marks the end of the dinosaurs
and the beginning of a new geological area, the Tertiary.
The extinction event is also often called the K-T extinction event.
This could be the end of our story.
The asteroid hit the earth and killed of all the dinosaurs.
Subscribe! ; )
But wait not so quick!
Some scientists are actually saying that the chicxulub impact of the meteorite
happened 300.000 years before the dinosaurs went extinct.
This would mean that there is another (additional) cause for the dinosaur extinction.
Other phenomena like a drop in temperature
like global climate change or increased volcanic activity
have been proposed to have affected the dinosaurs.
The debate on which of those factors actually caused the dinosaur extinction is quite heated.
But a publication just a few weeks ago actually showed
that the chicxulub impact and the K-T boundary
are actually very close together on a timescale.
So with improved measurements of the age in drilling cores
scientists could link both events and show that they fall into the same time.
Therefor is was concluded that the chicxulub impact
did indeed kill the dinosaurs.
However the scientist also stress
that the dinosaurs were already badly affected by things like climate change
or volcanic activity when the meteorite hit them.
I think it's quite funny to observe that some scientists are really into their theories.
So they say it really has to be the meteorite, or what not.
And they seem to forget some times that probably all of those effects combined did actually kill the dinosaurs.
I as a biologist worry less about the individual events
but more about the environmental changes that each event triggered.
To understand the extinction of the dinosaurs
we need to find out why the dinosaurs were not able to adapt
to the strong environmental changes.
Because some mammals and also a lot of other groups did intact
survive the impact event and the harsh conditions.
So let's think about what the conditions on the planet could look like
after the asteroid impact.
The asteroid for sure will have disturbed a lot of matter, that is going into the air.
So the whole atmosphere was basically full of airborne dust
so very few light could actually go onto the ground.
This probably led to a lot of plants die of
and very simple plants like ferns took over.
With less sunlight from the sun
there would be less energy, less food for other organisms
so this could have been a big problem for very big dinosaurs because they might not be able to find enough food.
However we also have some small dinosaurs, so why didn't they survive.
Well this could maybe be explained by a drop in global temperature
because most dinosaurs are believed to be coldblooded.
And therefor they would be more susceptible
to pathogens like fungi or viruses.
Mammals on the other hand, which are warmblooded
we all maintain our body temperature
might have been able to cope much better with pathogens
because they could increase their temperature.
We are still doing this sometimes today when we are sick
we develop a fever.
So we increase our body temperature to kill of the pathogens.
However this can not be the only reason why mammals were so successful
because also some reptiles who are cold blooded like most dinosaurs
could survive the harsh conditions.
So there have to be some additional factors
that prevented the dinosaurs from surviving.
Maybe let me know in the comment section if you have some ideas.
I did say that most dinosaurs are coldblooded
however there was one group that potentially was warmblooded.
And this group is intact still around today.
And those are the birds.
While most people are saying that dinosaurs generally went extinct
this is not true, some dinosaurs did survive and evolve into birds.
So dinosaur are still among us.
In fact you can take a look at the dinosaur fossil Archeopterix in Berlin,
which is showing a key step of the evolution of the dinosaur to the birds we see fling around today.
To make this clear again
dinosaurs are not extinct, we are just calling them birds today.
While the evolution of dinosaurs to birds is widely accepted
scientists are still trying to find out the last details of the dinosaur extinction.
Let's hope that scientists reach a consensus on the environmental triggers
and look more toward the question why dinosaurs were not able to adapt to the environmental changes.
So with a big dinosaur *RAWWW*
I say thank you for watching
and until next time, bye bye!
