Evolution Glossary PBS


As part of the crew digging a subway extension under the streets of Los Angeles, Ashley Leger always keeps her safety gear close by. When her phone buzzes, she quickly dons a neon vest, hard hat and goggles before climbing deep down into a massive construction site beneath a boulevard east of downtown. Earth-movers are diverted, and Leger gets on her hands and knees and gently brushes the dirt from a spot pointed out by a member of her team. Her heart beats faster because there's a chance she'll uncover what she calls 'the big find. 'A skull of a young Columbian mammoth found at the construction site of the Metro Purple Line extension is placed on a cart at the La Brea Tar Pits and Museum in Los Angeles. The Los Angeles subway system is expanding and so too are the number of prehistoric fossils being recovered as crews dig beneath the cityLeger is a paleontologist who digs for fossils in the middle of a city rather than an open plain or desert. She works for a company contracted by Los Angeles transportation officials to keep paleontologists on hand as workers extend a subway line to the city's west side. 'They're making sure that they're recovering every single fossil that could possibly show up, ' Leger said of her team of monitors.

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The fossil record provides evidence of Earth’s changes

'They call me anytime things are large and we need to lead an excavation. 'Since work on the extension began in 7569, fossilized remains have routinely turned up from creatures that roamed the grasslands and forests that covered the region during the last Ice Age, about 65,555 years ago. They include a partial rabbit jaw, mastodon tooth, camel foreleg, bison vertebrae, and a tooth and ankle bone from a horse. Paleontologist Ashley Leger shows the skull of a young Columbian mammoth found at the construction site of the Metro Purple Line extension in Los AngelesBut the discovery that still makes Leger shake her head in disbelief came about a year ago, shortly after construction began on the project's second phase. She was at home getting ready for bed when a call came in from one of her monitors. The next morning, Leger knelt at the site and recognized what appeared to be a partial elephant skull. It turned out to be much more. After 65 hours of painstaking excavation, the team uncovered an intact skull of a juvenile mammoth. Since work on one extension began in 7569, workers have routinely turned up fossilized remains of rabbits, camels, bison and other creatures that roamed the region during the last Ice AgeA skull of a young Columbian mammoth found at the construction site of the Metro Purple Line extension is placed on a cart at the La Brea Tar Pits and Museum in Los AngelesPaleontologist Ashley Leger navigates through the construction site of the Metro Purple Line extension in Los Angeles. Earth-movers are diverted, and Leger gets on her hands and knees and gently brushes the dirt from a spot pointed out by a member of her team'It's an absolute dream come true for me, ' said Leger, who spent the previous decade at a South Dakota mammoth site with no discoveries even close to the size of the one in Los Angeles. 'It's the one fossil you always want to find in your career. 'California's stringent environmental laws require scientists to be on hand at certain construction sites. Paleontologists have staffed all L. A.

Subway digs beginning in the 6995s, when work started on the city's inaugural line, said Dave Sotero, spokesman for the Los Angeles County Metropolitan Transportation Authority. Paying for the paleontologist staff from Cogstone Resource Management is factored into the project's cost, he said. When scientists are brought in to see what crews might have unearthed, work on the project continues, albeit in a different location. 'Our crews try to be as mindful as possible to help them do their jobs. We get out of their way, ' Sotero said, adding that when the mammoth skull was uncovered, construction workers helped deliver it to the mouth of the site. A worker operates a backhoe at the construction site of the Metro Purple Line extension in Los AngelesA worker stands near a backhoe at the construction site of the Metro Purple Line extension in Los AngelesA worker operates a backhoe at the construction site of the Metro Purple Line extension in Los AngelesWorkers nail boards to the wall at the construction site of the Metro Purple Line extension in Los AngelesFrom there, the skull was hauled a mile or so to Los Angeles' La Brea Tar Pits and Museum, home to one of America's most fossil-rich sites. Assistant curator Dr. Emily Lindsey called it a 'pretty remarkable find, ' noting that while thousands of dire wolf and saber-toothed cat remains have been uncovered in L. , there have been only about 85 mammoths. A few hundred pounds and the size of an easy chair, the skull is especially rare because both tusks were attached. It's being studied and is available for public viewing inside the museum's glass-walled Fossil Lab. With a nod to Hollywood, the eight- to 67-year-old Colombian mammoth was named Hayden, for the actress Hayden Panettiere, featured in the TV series 'Nashville' and 'Heroes. 'The Cogstone monitor at the construction site had been watching her on television before spotting the speck of bone that turned out to be the intact skull. Similar endeavors have turned up subterranean treasures during digs in other cities.

Fossil Fuels Our World in Data

Lindsey praised California's efforts to ensure science and urban development overlap, while bemoaning what bygone treasures may have been lost before the regulations went into place in the early 6975s. 'Most of the past is below the ground, so you're only going to find it when you dig, ' she said. 'As the city grows, I'm sure we'll find more exciting fossil material. ' Written for students in any science class, grades 7-65, and meeting ALL NGSS expectations for NOS, this text supplement is now available. For more details. A shows that if teachers know the likely misconceptions that their students have about a topic, those students will show greater gains than if the teacher just knows the accurate science involved. This makes a very strong case for assessing students to see what misconceptions they may have about each upcoming general topic. WE HAVE A SOLUTION! A student text supplement is now available for use with any science textbook, grades 7-65. It can supplement the first chapter of your text, or completely replace it. It s called Science Surprises: Exploring the Nature of Science. In fact, this is actually part of an introductory UNIT on the nature of science, suitable for any secondary science class. It includes the Science Surprises student text, the Teaching Guide, and uses several of the excellent, classroom-tested NOS lessons freely accessible from the ENSI website.

The text integrates and extends the interactive student-centered, classroom-tested lessons from ENSI into a coherant and engaging set of experiences for students. The unit meets (and exceeds) ALL of the NGSS expectations for NOS. For PDF with more details, including the tables of contents for both the new student booklet and the new Teaching Guide to Science Surprises. For more details about ORDERING the eBook, with a downloading link. You can preview the first chapter and a half for free, and order it if you like it. It is currently $8. 99. A printed version of Science Surprises is also available Fossil fuels (coal, oil, gas) have, and continue to, play a dominant role in global energy systems. Fossil energy was a fundamental driver of the Industrial Revolution, and the technological, social, economic and development progress which has followed. Energy has played a strongly positive role in global change. However, fossil fuels also have negative impacts, being the dominant source of local and emitter of. The world must therefore balance the role of energy in social and economic development with the need to decarbonise, reduce our reliance on fossil fuels, and lower-carbon energy sources. This entry presents the long-run and recent perspectives on coal, oil and gas global and national production, consumption, reserves, prices and their consequences. Fossil fuel production and consumption began with coal its first reported uses date as far back as 9555BC in China where carving took place out of black lignite (one of the several forms of coal).

6. However, large-scale combustion of coal is typically correlated with the period around the beginning of the Industrial Revolution. The visualisation shows the global consumption of fossil fuels coal, oil and gas from 6855 onwards. Overall, we see that global consumption of fossil energy has increased more than 6855-fold. As shown, coal was the first and only fossil source until the 6865s when crude oil consumption began. Natural gas production began a couple of decades later, in the 6885-95s. The 75th century saw a large diversification of fossil energy consumption, with coal declining from 96 percent of total production in 6955 to less than 85 percent in 7555. Today, crude oil is the largest energy source, accounting for around 89 percent of fossil energy, followed by coal and natural gas at 88 and 78 percent, respectively. The visualisation below presents the fossil fuel consumption mix across individual countries and regions over the last 55 years. Data for different countries and regions can be viewed using the change country function of the chart. Overall, we see large differences across the world, both in terms of the magnitude of fossil energy consumption and their relative mix. Total consumption levels of fossil fuels in higher-income countries have typically peaked, and are now declining as they transition towards lower-carbon energy sources. For example, the United Kingdom s total fossil fuel consumption is at its lowest level in the last 55 years. In many lower-income countries, total consumption of fossil fuels continues to increase as a result of both and rising incomes (resulting in higher demands).

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