A Cretaceous origin for placental mammals, the group that includes humans, dogs and bats, has been revealed by in-depth analysis of the fossil record, showing they co-existed with dinosaurs for a short time before the dinosaurs went extinct.
The catastrophic destruction triggered by the asteroid hitting the Earth resulted in the death of all non-avian dinosaurs in an event termed the Cretaceous-Paleogene (K-Pg) mass extinction. Debate has long raged among researchers over whether placental mammals were present alongside the dinosaurs before the mass extinction, or whether they only evolved after the dinosaurs were done away with. Fossils of placental mammals are only found in rocks younger than 66 million years old, which is when the asteroid hit Earth, suggesting that the group evolved after the mass extinction. However, molecular data has long suggested an older age for placental mammals.
In a new paper published in the journal Current Biology, a team of palaeobiologists from the University of Bristol and the University of Fribourg used statistical analysis of the fossil record to determine that placental mammals originated before the mass extinction, meaning they co-existed with dinosaurs for a short time. However, it was only after the asteroid impact that modern lineages of placental mammals began to evolve, suggesting that they were better able to diversify once the dinosaurs were gone.
The researchers collected extensive fossil data from placental mammal groups extending all the way back to the mass extinction 66 million years ago.
Lead author Emily Carlisle of Bristol’s School of Earth Sciences said: “We pulled together thousands of fossils of placental mammals and were able to see the patterns of origination and extinction of the different groups. Based on this, we could estimate when placental mammals evolved.”
Co-author Daniele Silvestro (University of Fribourg) explained: “The model we used estimates origination ages based on when lineages first appear in the fossil record and the pattern of species diversity through time for the lineage. It can also estimate extinction ages based on last appearances when the group is extinct.”
Co-author Professor Phil Donoghue, also from Bristol, added: “By examining both origins and extinctions, we can more clearly see the impact of events such as the K-Pg mass extinction or the Paleocene-Eocene Thermal Maximum (PETM).”
Primates, the group that includes the human lineage, as well as Lagomorpha (rabbits and hares) and Carnivora (dogs and cats) were shown to have evolved just before the K-Pg mass extinction, which means their ancestors were mingling with dinosaurs. After they survived the asteroid impact, placental mammals rapidly diversified, perhaps spurred on by the loss of competition from the dinosaurs.
No shit.
Of course human ancestors were around when the dinosaurs disappeared and there is no explanation why they didn’t all become extinct is there so science knows absolutely nothing but very good at guessing. I make a decoration that it was not an asteroid that killed the dinosaurs because that would have wiped out everything and it did not so something else is the answer not the asteroid b*******.
I want to now if I have ancestors when the dinosaurs were alive
have you been on Israel? I am asking because all answers are there of beginning of humanity!
I love how every reply besides “no shit” has terrible grammar and spelling. The great minds of the time.
Is this the only lineage of humanity tracing back through the period?
It is believed that humans and dinosaurs did track together in this period.
Do we know this to be true?
Thats because we are the one that teraformed this planet. There was no astoroid. We destroyed this planet to male it livable for us. Why would all dinasours be extint around the whole planet? There was plenty of places that they could hide.
I always knew cats were smarter then dinosaurs. They also have nine lives so it makes sense how they survived. Eventually my ancestors must have evolved from some of those cats. It explains why I’m so moody. It also explains why so many people believe all this theoretical science bull? Their educated guesses seem often predominantly baseless. Some mammals died when dinosaurs died. That’s the fact. Mammals and likely humans existed when dinosaurs existed. When is more or less a world view question. Who and what are you putting your faith in?
Is there a citation for where this information came from?
This article is a bunch of lies and misinformation. There never was a cretaceous period or Jurassic period, nothing has ever evolved, there is no such thing as a fossil record and an asteroid didn’t wipe out the dinosaurs and other creatures. The reason we have fossils in the dirt is cause of the Great Flood that covered the earth a long time ago just as the Bible says. God sent the flood and judged the earth.
Almost correct. Humans did live with dinosaurs but it was not death by asteroids. It was a world flood and all land creatures died along with all humans. But one human and family was saved on an ark. We have our dating wrong as we look in the fossil record. The flood receding made massive changes in a short period of time. It takes more faith to believe that detail and order is created out of chaos than to believe in a God that had mercy on His creation that turned to their own way. Thank God for saving the human race again with the death and resurrection of Jesus Christ! This is the biggest event in human history!
Gawd! So many ‘expert’ 😆 armchair paleontologists on this thread! Here’s an idea: instead of hypothesizing something that goes against what this article says even though you have no basis in fact to make such an hypothesis, why don’t you get off your collective butts and do the work and put some facts behind your bogus declarations! If not, STFU and leave it to the experts who literally devote their entire professional lives researching this stuff.
Oh thank God I thought I was extinct.
The fact we’re here I’d say is a pretty strong indication that our ancestors survived everything up to now.