Neanderthal extinction could have been driven by ...

 What Caused Neanderthals To Go Extinct?Smithsonian Insider – August 11, 2015 (Homo neanderthalensis) were widespread across Europe and Western Asia for a long time, starting about 400,000 years ago. But things began to change when populations of?Homo sapiens?(earlier members of our own species) migrated from Africa to Europe at about 45,000 years ago. Five thousand years later not a single Neanderthal remained. What happened? To find out, Smithsonian Insider?posed a seemingly simple question to Dr. Briana Pobiner, paleoanthropologist (scientist who studies ancient human remains) at the Smithsonian’s National Museum of Natural History.Q: So, why exactly did Neanderthals go extinct?Pobiner:?It is hard to know exactly why many species are on the verge of extinction now, let alone species in the deep past that are already gone. However, we can assume some of the same basic ecological processes driving animals to extinction today?are part of the puzzle. In the case of Neanderthals, we think competition and changes to their habitat due to climate change were two of the main factors.Neanderthals were fairly specialized to hunt large, Ice Age animals like mammoth and bison. But sometimes being specialized isn’t such a good strategy. When climates changed and some of those animals went extinct, the Neanderthals may have been more vulnerable to starvation. Moreover, their large heavy spears were only good for thrusting at animals at close range. They would not have been useful for hunting swifter animals like deer or elk.We also think?Homo sapiens?had a competitive edge over Neanderthals. There is evidence that early?Homo sapiens?had long-distance trade networks, possibly buffering them against times of climate change when their preferred foods were not available; Neanderthals did not.Neanderthals had physical features that helped them survive cold climates, like large noses to humidify and warm dry, cold air and short, stout bodies to conserve heat, but early?Homo sapiens?had technology that Neanderthals didn’t, including sewing needles to make clothing, important during the colder periods of the Ice Ages.?Homo sapiens?also had innovative tools like bows and arrows that allowed them to hunt from animals from a distance, like deer or elk, and seemed to have had a more diverse diet than Neanderthals.We don’t have evidence of direct combat between the two species, but we know they interacted, because they interbred. Some would say Neanderthals didn’t go extinct, because everyone alive today whose ancestry is from outside of Africa (where Neanderthals never lived) carries a little bit of Neanderthal DNA in their genes. It is quite possible that because Neanderthals tended to live in smaller bands and tribe, that they just eventually blended into the general population of Homo sapiens.What caused Neanderthals to go extinct?DirectionsPart 1:Before Reading: Take a guess on which of the following claims you think is true by placing a check mark (?) next to that claim. 1. _____Neanderthals died off due to competition for resources.2. ______Neanderthals went extinct due to climate change.3. ______Neanderthals were killed off by Homo sapiens. 4. _______Neanderthals lacked advanced technology.5. _______Neanderthals blended into the general Homo sapiens population.Now let’s do some reading. Use the section below to take notes while you are reading.Part 2:After Reading: With your table group, go back and re-read the article. As you read, find evidence to eliminate the claims that don’t work and cross them off. 1. _____Neanderthals died off due to competition for resources.Is there evidence for this claim? Yes or No If yes, what is the evidence?2. ______Neanderthals went extinct due to climate change.Is there evidence for this claim? Yes or No If yes, what is the evidence?3. ______Neanderthals were killed off by Homo sapiens. Is there evidence for this claim? Yes or NoIf yes, what is the evidence?4. _______Neanderthals lacked advanced technology.Is there evidence for this claim? Yes or NoIf yes, what is the evidence?5. _______Neanderthals blended into the general Homo sapiens population.Is there evidence for this claim? Yes or NoIf yes, what is the evidence?Part 3: Rank the evidence in order from most believable to least believable, and explain why.Most Believable: ______________________________________________________________________Why: _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Believable: ___________________________________________________________________________Why: __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Somewhat Believable: __________________________________________________________________Why: __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Kind of Believable: _____________________________________________________________________Why: __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Least Believable: _______________________________________________________________________Why: __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________**Which of the above do you consider to be the Trigger Event, and why?_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Part 4: ?Which theory is the trigger event or the most probable cause for Neanderthals going extinct? Complete the CER below:Claim: ?I believe that Neanderthal went extinct because….Evidence: The evidence that best supports my claim is….Reasoning: The reason my evidence supports my claim is….Now read this additional source on Neanderthal extinction to see if your claim is still credible:Neanderthal extinction could have been driven by inbreeding, demographic issues — not modern humans"Our results indicate that the disappearance of Neanderthals might have resided in the smallness of their population(s) alone," the paper's abstract reads.byAlexandru MicuNovember 29, 2019Small populations and inbreeding may have driven the Neanderthals extinct, new research suggests.Neanderthals disappeared sometime around 40,000 years ago, about the same time as modern humans began moving into Europe and the Near East. Because of the timing, it’s often held that modern humans helped drive our ancient relatives extinct, but this theory hasn’t been confirmed or infirmed up to now.A new study looked at the population dynamics of Neanderthal groups in a bid to gain insight into their extinction. Through the use of demographic modelling, the team tried to establish if internal factors helped drive the Neanderthals out of history — and whether they were headed for collapse on their own, without the ‘help’ of modern humans.Family ties“Our results indicate that the disappearance of Neanderthals might have resided in the smallness of their population(s) alone,” the paper’s abstract reads. “Even if they had been identical to modern humans in their cognitive, social and cultural traits, and even in the absence of inter-specific competition, Neanderthals faced a considerable risk of extinction.”The team used data from hunter-gatherer populations today as a guideline for their modeling efforts. After observing how these groups operate, the team developed population models for Neanderthal groups of various initial sizes: 50, 100, 500, 1,000, and 5,000 individuals.The team then mixed in the effects of inbreeding, Allee effects (where reduced population size negatively impacts individuals’ fitness), and random demographic fluctuations (caused by shifting births, deaths, and sex ratios) into their simulated societies and observed the results. What they wanted to determine was if these factors were enough to drive the communities to extinction over a 10,000-year period.Inbreeding alone was likely not enough to drive most Neanderthals to extinction. The team notes that it only led to the collapse of the smallest population modeled for the study. However, Allee effects could cause the extinction of populations up to 1,000 individuals strong when 25% of fewer Neanderthal females gave birth within a given year (the team reports that this is a common birth rate in hunter-gatherer societies today. When all three factors were together (inbreeding + Allee effects + demographic fluctuations), all the populations modeled in the study died out within 10,000 years.Being based on computer models — which themselves are based on modern human hunter-gatherers — means that the findings should be taken with a grain of salt. While the models can’t account for everything, they do give us a general idea of what was happening to the Neanderthals at the time, the team reports.It’s possible that the encroachment of modern humans impacted the Neanderthals in ways that promoted inbreeding and subsequent Allee effects, which obviously could not be accounted for by the models. However, even in the absence of modern humans, Neanderthals were headed to extinction due to their demographic issues, according to the findings.The paper “Inbreeding, Allee effects and stochasticity might be sufficient to account for Neanderthal extinction” has been published in the journal PLOS ONE.Part 5: ?Retesting your claim: Was your initial claim about Neanderthal extinction correct? Complete the CER below by adding any additional information that either backs-up your initial claim, or explain how your claim is challenged by the additional information:Claim: ?I believe that Neanderthal went extinct because….Evidence: The evidence that best supports my claim is….Reasoning: The reason my evidence supports my claim is…. ................
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