The Bering Land Bridge Between Russia and North America

The Bering Land Bridge Between Russia and North America The Bering Strait is a waterway that separates Russia from North America. It lies above the Bering Land Bridge (BLB), also called Beringia (sometimes misspelled Beringea), a submerged landmass that once connected the Siberian mainland with North America. While Beringias shape and size while above water is variously described in publications, most scholars would agree the land mass included the Seward Peninsula, as well as existing land areas of northeast Siberia and western Alaska, between the Verkhoyansk Range in Siberia and the Mackenzie River in Alaska. As a waterway, the Bering Strait connects the Pacific Ocean to the Arctic Ocean over the polar ice cap, and eventually the Atlantic Ocean. The climate of the Bering Land Bridge (BLB) when it was above sea level during the Pleistocene was long thought to have been primarily a herbaceous tundra or steppe-tundra. However, recent pollen studies have shown that during the Last Glacial Maximum (say, between 30,000-18,000 calendar years ago, abbreviated as cal BP), the environment was a mosaic of diverse but cold plant and animal habitats. Living on the Bering Land Bridge Whether Beringia was habitable or not at a given time is determined by the sea level and presence of surrounding ice: specifically, whenever the sea level drops about 50 meters (~164 feet) below its present position, the land surfaces. The dates when this happened in the past have been difficult to establish, in part because the BLB is currently mostly underwater and difficult to reach. Ice cores seem to indicate that most of the Bering Land Bridge was exposed during Oxygen Isotope Stage 3 (60,000 to 25,000 years ago), connecting Siberia and North America: and the land mass was above sea level but cut off from east and west land bridges during OIS 2 (25,000 to about 18,500 years BP). Beringian Standstill Hypothesis By and large, archaeologists believe that the Bering land bridge was the primary entryway for the original colonists into the Americas. About 30 years ago, scholars were convinced that people simply left Siberia, crossed the BLB and entered down through the mid-continental Canadian ice shield through a so-called ice-free corridor. However, recent investigations indicate the ice-free corridor was blocked between about 30,000 and 11,500 cal BP. Since the northwest Pacific coast was deglaciated at least as early as 14,500 years BP, many scholars today believe a Pacific coastal route was the primary route for much of the first American colonization. One theory gaining strength is the Beringian standstill hypothesis, or Beringian Incubation Model (BIM), the proponents of which argue that instead of moving directly from Siberia across the strait and down the Pacific coast, the migrants livedin fact were trappedon the BLB for several millennia during the Last Glacial Maximum. Their entry into North America would have been blocked by ice sheets, and their return to Siberia blocked by the glaciers in the Verkhoyansk mountain range. The earliest archaeological evidence of human settlement to the west of the Bering Land Bridge east of the Verkhoyansk Range in Siberia is the Yana RHS site, a very unusual 30,000-year-old site located above the arctic circle. The earliest sites on the east side of the BLB in the Americas are Preclovis in date, with confirmed dates usually no more than 16,000 years cal BP. Climate Change and the Bering Land Bridge Although there is a lingering debate, pollen studies suggest that the climate of the BLB between about 29,500 and 13,300 cal BP was an arid, cool climate, with grass-herb-willow tundra. There is also some evidence that near the end of the LGM (~21,000-18,000 cal BP), conditions in Beringia deteriorated sharply. At about 13,300 cal BP, when rising sea levels began to flood the bridge, the climate appears to have been wetter, with deeper winter snows and cooler summers. Sometime between 18,000 and 15,000 cal BP, the bottleneck to the east was broken, which allowed human entrance into the North American continent along the Pacific coast. The Bering Land Bridge was completely inundated by rising sea levels by 10,000 or 11,000 cal BP, and its current level was reached about 7,000 years ago. The Bering Strait and Climate Control A recent computer modeling of the ocean cycles and their effect on abrupt climate transitions called Dansgaard-Oeschger (D/O) cycles, and reported in Hu and colleagues 2012, describes one potential effect of the Bering Strait on global climate. This study suggests that the closing of the Bering Strait during the Pleistocene restricted cross-circulation between the Atlantic and Pacific Oceans, and perhaps led to the numerous abrupt climatic changes experienced between 80,000 and 11,000 years ago. One of the major fears of coming global climate change is the effect of changes in the salinity and temperature of the North Atlantic current, resulting from glacial ice melt. Changes to the North Atlantic current have been identified as one trigger for significant cooling or warming events in the North Atlantic and surrounding regions, such as that seen during the Pleistocene. What the computer models seem to show is that an open Bering Strait allows ocean circulation between the Atlantic and Pacific, and continued admixing may suppress the effect of the North Atlantic freshwater anomaly. The researchers suggest that as long as the Bering Strait continues to stay open, the current water flow between our two major oceans will continue unhindered. This is likely to repress or limit any changes in the North Atlantic salinity or temperature, and thus lessen the likelihood of sudden collapse of the global climate. Researchers caution, however, that since researchers arent even guaranteeing that fluctuations in the North Atlantic current would create problems, further investigations examining glacial climate boundary conditions and models are needed to support these results. Climate Similarities between Greenland and Alaska In related studies, Praetorius and Mix (2014) looked at the oxygen isotopes of two species of fossil plankton, taken from  sediment cores  off the Alaskan coast, and compared them to similar studies in northern Greenland. Briefly, the balance of isotopes in a fossil being is direct evidence of the kind of plantsarid, temperate, wetland, etc.which were consumed by the animal during its life. What Praetorius and Mix discovered was that sometimes Greenland and the coast of Alaska experienced the same kind of climate: and sometimes they did not. The regions experienced the same general climate conditions from 15,500-11,000 years ago, just before the abrupt climate changes that resulted in our modern climate. That was the onset of the Holocene when temperatures rose sharply, and most of the glaciers melted back to the poles. That may have been a result of the connectivity of the two oceans, regulated by the opening of the Bering Strait; the elevation of ice in North America and/or the routing of freshwater into the North Atlantic or Southern ocean. After things settled down, the two  climates  diverged again and the climate has been relatively stable since then. However, they appear to be growing closer. Praetorius and Mix suggest that the simultaneity of climates may presage rapid climate change and that it would be prudent to monitor the changes. Sources This glossary entry is part of the About.com  Guide to Populating America  and the  Dictionary of Archaeology. Bibliographic sources for this article are on  page two. Ager TA, and Phillips RL. 2008. Pollen evidence for late Pleistocene Bering land bridge environments from Norton Sound, northeastern Bering Sea, Alaska.  Arctic, Antarctic, and Alpine Research  40(3):451–461. Bever MR. 2001. An Overview of Alaskan Late Pleistocene Archaeology: Historical Themes and Current Perspectives.  Journal of World Prehistory  15(2):125-191. Fagundes NJR, Kanitz R, Eckert R, Valls ACS, Bogo MR, Salzano FM, Smith DG, Silva WA, Zago MA, Ribeiro-dos-Santos AK et al. 2008. Mitochondrial Population Genomics Supports a Single Pre-Clovis Origin with a Coastal Route for the Peopling of the Americas.  The American Journal of Human Genetics  82(3):583-592. doi:10.1016/j.ajhg.2007.11.013 Hoffecker JF, and Elias SA. 2003. Environment and archeology in Beringia.  Evolutionary Anthropology  12(1):34-49. doi:10.1002/evan.10103 Hoffecker JF, Elias SA, and ORourke DH. 2014. Out of Beringia?  Science  343:979-980. doi:10.1126/science.1250768 Hu A, Meehl GA, Han W, Timmermann A, Otto-Bliesner B, Liu Z, Washington WM, Large W, Abe-Ouchi A, Kimoto M et al. 2012.  Role of the Bering Strait on the hysteresis of the ocean conveyor belt circulation and glacial climate stability.  Proceedings of the National Academy of Sciences  109(17):6417-6422. doi: 10.1073/pnas.1116014109 Praetorius SK, and Mix AC. 2014.  Synchronization of North Pacific and Greenland climates preceded abrupt deglacial warming.  Science  345(6195):444-448. Tamm E, Kivisild T, Reidla M, Metspalu M, Smith DG, Mulligan CJ, Bravi CM, Rickards O, Martinez-Labarga C, Khusnutdinova EK et al. 2007.  Beringian Standstill and Spread of Native American Founders.  PLoS ONE  2(9):e829. Volodko NV, Starikovskaya EB, Mazunin IO, Eltsov NP, Naidenko PV, Wallace DC, and Sukernik RI. 2008. Mitochondrial Genome Diversity in Arctic Siberians, with Particular Reference to the Evolutionary  History of Beringia and Pleistocenic Peopling of the Americas.  The American Journal of Human Genetics  82(5):1084-1100. doi:10.1016/j.ajhg.2008.03.019

How To Plan Your Product Roadmap Like CoSchedule (+ Free Template) - CoSchedule Blog

How To Plan Your Product Roadmap Like (+ Free Template) Blog We just completed our second ever product roadmap summit  here at .  This is where a group of us spends a full day locked in a conference room fighting relentlessly for the features that you need and deserve in your favorite editorial calendar. During this process, we review recent (and some older)  feature requests, balance maintenance needs, and read through our ever-growing wish-list of features for . The goal? Decide what were going to build over the next six months. It’s sort of like decide who we want to be when we grow up twice a  year. For us, it follows a simple 6-6-6 framework. This covers planning in three timeframes after  the day of the summit: 6 weeks, 6 months, and 6 years. We hold product roadmap summits twice per year and use them to think about our future (6 years), our next two quarters (6 months), and some of our immediate goals (6 weeks). How To Plan Your #ProductRoadmap Like (+ Free Template)So, why do we do this? If there is only one truth in business, it’s that there is never a shortage of ideas. Plus, our customers are awesome and send us a ton of ideas that we usually love and want to build immediately. But, alas, there are only 25 of us. We just can’t do it all. With so many inputs, its important that we balance the things that we  could do, to actually realize the things that we can do. And so, we have a product roadmap summit and  pick a handful of things that will bring the most results. We all need a system for prioritizing our work. This is how we do it at . Its important to balance what you could do, to realize what you can do.Get Your Free Product Roadmap Template To Plan Now This blog post walks you through the exercises that work for choosing the ultimate best features for you to plan into your project development roadmap. Get your free kit now to plan your roadmap as you read this post. Your kit includes: Product roadmap summit Word doc template to help you run an efficient planning session with your team. Product roadmap template Excel spreadsheet to help you prioritize the projects you choose to tackle in the next six weeks to  six months. Step #1: Establish Your BHAG (6-Year Goal) BHAG stands for big, hairy, audacious goal. It’s  an idea from the book, Built to Last  by James Collins and Jerry Porras. According to Collins and Porras, a BHAG is a long-term goal that changes the very nature of a business' existence. At the beginning of every product roadmap summit, we start with this goal. We review the BHAG from the previous summit and do a few brainstorming exercises. We allow for general team discussion about the goal. Does this still reflect where we want to go? We brainstorm some of the big things that we will need to accomplish in order to reach our BHAG. We list the threats that will prevent us from ever reaching our BHAG. The entire goal here is to set the stage for our roadmap planning by considering where we want to go and working backward. It’s a favorite strategy of mine. Deciding WHAT NOT to do is way easier than deciding WHAT to do. Say no, then work backwards from there. #startup pic.twitter.com/2RTWsO1fgI Garrett Moon (@garrett_moon) June 24, 2016 The hope is that by bringing this goal to mind, we will continuously refer back to our BHAG as we do our planning. You should always  be using your BHAG to evaluate the things you're doing in the present. Are you doing what you need to do to get there? Step #2: Put It All On The Table The next, and most exciting, portion of our product roadmap summit includes the airing of many grievances, err†¦ feature requests! The goal here is to get everything on a Post-It note on the wall so you can see it together. We like to have one person from each of our core teams (product, marketing, and success) share a list of feature requests, customer comments, growth opportunities, and smart things that we could build. Let every idea be a good idea as you brainstorm.Here’s how it works: Lance from our customer success team shares the list of feature requests from our customers. This list is pre-sorted by the entire customer success team and should show us the key areas where our customer would like to see us improve. Next, we have Justin, our CTO, share a list of platform and maintenance projects that need to be completed in order to maintain the quality of service that our customers demand and deserve. This list usually includes foreign sounding things like database maintenance, spindle logs, and very excited engineers. We don’t always understand it, but we do love it. The third thing we cover is sales and marketing needs. These are usually covered by myself and usually include improvements that we want to make to our billing system, onboarding/first-run experience, or other areas that are related directly to our core business metrics like trial to paid conversions, user churn, and product growth. The fourth thing we like to cover is our feature backlog. This backlog is lengthy and includes a mixture of features that we want to see and ideas from one of our previous summits that had to go on the back burner. During this phase, it's important that you don’t get carried away categorizing and prioritizing things. There will be time for that later. Just get it out there, let every idea be a good one, and move forward. Step #3: Team Lunch Next, lunch. There are usually only two rules for team lunch. Leave the meeting room behind. We think it's important to get out of the building to  clear our heads for a bit. You don’t have to talk about business. It doesn’t mean you can’t, but we like to allow the conversation to take us wherever it goes. It’s a good way to break up a busy day. Step #4: Prioritize This is the hardest part of the process. This is when we take all of the ideas on the table, evaluate them against the BHAG, and prioritize them based on what we would like to accomplish in the next six  months. We use several methods for breaking things down. We break things down into roadmaps. Rather than trying to prioritize apples against oranges, we like to break things into a few different groups. For us, this means that we build three distinct roadmaps for our team: Features, Success, and Platform. Each of these roadmaps has their own goals. We are only trying to figure out what to build next in each of these categories. We prioritize ideas based on potential customer value.  We like to place each feature idea on a simple X/Y table that looks like this: In this example, the Y axis represents the amount of value we believe that a feature or idea can bring our users. The X axis represents the total number of users, or percentage of users, who will be able to take advantage of the mentioned improvement. Plotting this out is usually the most taxing part of our entire day. For every single Post-It note, we debate and decide where the idea falls in the spectrum. We try not to overthink it, but it can still take awhile. Plot ideas on an X/Y table to choose features with the best value for the  most users.The efforts always result in a ton of useful dialogue and debate across our team. This process  also weeds out any â€Å"pet features† that someone on our team may have. The more we concentrate on user value, the less likely we are to make a call based on personal bias. When we are done, it will look something like this. In this case, one thing is for sure, the customer is always right! Step #5: Assemble The Product Roadmap Once everything is plotted out, we draw a (figurative) line across the X/Y axis. Anything that falls below or to the left of the line probably won’t get done. One thing that I want to emphasize is that this doesn’t mean those items aren’t important, or that they will never get built. It simply means that they aren’t important in relation to the other items on the list. We always re-review the cut ideas at the next product roadmap summit. At this point, we begin dividing things in to 6-week and 6-month groups. What things do we want to get done right now (six weeks), and what things needs to get done soon, but not right away (six  months)? There is plenty of additional discussion at this point, but by and large, most of the team will be on the same page because of the previous exercise that ranked features by user value. While I am not going to go too far into it here, we also use a point system to define how large a feature is, or more importantly, how much time and resources it will require to develop. For us, this is a simple 1, 2, 3 point system. You could adapt them for your team as needed. And that’s how we plan features at ! When it’s all said and done, we have a product roadmap, a happy team, and customers who are getting the features that will help them the most! Before I wrap things up, I want a cover a few additional things just in case you decide to try and hold your own roadmap summit. Lessons Learned From Successful Product Roadmap Summits Quick Tip #1: Our Roadmap Summit Has Some Rules We use a few basic rules to ensure that we stay focused and on topic. You can add/remove as necessary, but here are the rules we use: We are brainstorming projects of the purpose of the product team, no other team projects can/should be added. All ideas are necessary for good brainstorming. Avoid shooting things down. Keep laptops closed and phones down. No email, HipChat/Slack, or Snapchat allowed! Someone should be designated to write things down. Don’t get too deep into features. We’re not building them here. Quick Tip #2: Everyone Has Veto Power During roadmap planning, we give everyone veto power. If they are absolutely convinced that a feature should not be completed, or want to call shenanigans on the group, they can. While Justin and I tend to use this rule more than others (oops!), it applies to everyone on the team equally. Quick Tip #3: Bring Snacks We like to leave a few piles of red starbursts on the tables for added sugar, but we also provide fruit, snacks, and refreshing drinks to keep everyone going. Quick Tip #4: Leave Time To Retro The last two things that we do after any roadmap summit are related to review and reflection. First, we spend at least 10 minutes reviewing our newly formed product roadmap against our BHAG and our earlier discussions. This is designed to ensure that we will actually be executing against the goals that we outlined. Is everything on our roadmap necessary in order to reach our BHAG? Is it in alignment with where we want to go? If it isn’t, now is the right time to reflect and adjust our plan. The second thing we do is an immediate retrospective on the meeting itself. The goal here is to identify potential improvements that we can implement to make to the process better during the next summit. We like to cover three questions: What went well? What didn’t go so well? What can we do to ensure things go (even) better next time? Best of luck to you and your team at your own product roadmap summit! If you give it a try, please let us know how it goes in the comments.