David Attenborough's First Life

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The experts

  • Professor Hazel Barton – Ecology of microbes that survive in harsh and extreme environments, Northen Kentucky University. In First Life she demonstrates the ability of extremeophile bacteria to survive on the surface of glaciers.
  • Dr Simon Braddy – Modern and prehistoric arthropods, University of Bristol.
  • Dr Jean-Bernard Caron – Curator of Invertebrate Paleontology, Royal Ontario Museum, and a world expert on the animals of the Burgess Shale.
  • Professor Bernie Degnan – Director of the Centre for Marine Science, University of Queensland whose research on sponges is featured in First Life.
  • Professor Phil Donoghue – Evolution in relation to embryology, University of Bristol. In First Life he uses an X-ray particle accelerator called a synchrotron to look inside tiny fossilized embryos.
  • Dr Mary Droser – Evolutionary radiations of ancient animals. She discovered the fossil of Funisia dorothea, an Ediacaran animal which portrays the earliest known example of sexual reproduction.
  • Professor Richard Fortey – Paleogeography and the evolution of arthropods, Natural History Museum. He is considered a leading expert in trilobites.
  • Dr Jim Gehling – Ecology of Ediacaran animals, South Australian Museum.
  • Professor Justin Marshall – Colour vision and deep-sea marine biology, University of Queensland. He researches mantis shrimps, top marine hunters with similarities to the first large predator, Anomalocaris.
  • Dr Guy Narbonne – Evolution of the first complex animals, Queen’s University, Canada. He is a leading expert on the animals of Mistaken Point.
  • Professor Patricia Vickers-Rich – World-renowned palaeontologist and expert on the origin and evolution of Ediacaran animals, Monash University, Australia.

The first cells

The first cells evolved on Earth around 3.5 billion years ago, but for 3 billion years the Earth was dominated by two groups of single-celled organisms: the bacteria and the archaea.

  • Lost City – Mineral-rich water seeping from hydrothermal vents in the Atlantic ocean floor deposited these towering carbonate spires. Scientists think single-celled life could have originated in pockets within these towers, 3.5 billion years ago.
  • Archaea – These ancient single-celled organisms may look like bacteria, but genetically they are as different from bacteria as we are. They thrive in extreme habitats such as deep sea vents and volcanic springs, in conditions similar to those of the early Earth.
  • Stromatolites – These rocky pillars are formed by colonial single-celled cyanobacteria, which trap energy from the sun by photosynthesis. Today they exist in only two locations in the world, but billions of years ago these colonial towers would have been common worldwide.
  • Snowball Earth Theory – Scientists believe that around 700 million years the surface of the Earth was nearly or completely frozen over.
  • Extremeophilic bacteria – These tough microorganisms  survived on the surface of ice and glaciers during the harsh conditions of Snowball Earth.

The dawn of multi-cellularity

Single-celled archaea and bacteria had dominated the globe for billions of years, but Snowball Earth changed everything. In an evolutionary blink of the eye, multi-cellular life appeared in the form of the most basic animals: sponges. As Snowball Earth came to an end, glaciers which had picked up tonnes of rock and churned it into sediment melted, carrying the nutrient-rich sediment into the ocean. The nutrients acted as a fertilizer, causing photosynthetic, oxygen producing bacteria similar to algae to multiply and fill the oceans. They pumped oxygen into the atmosphere, changing the course of evolution forever.

  • Eukaryotes – A video mini-lecture explaining how the first single-celled eukaryotic organisms, ancestors of animals, fungi and plants evolved from bacteria.
  • Algal blooms – Fertilizers flooding into water systems cause photosynthesizing algae to bloom out of control, just as photosynthesizing cyanobacteria bloomed after Snowball Earth.
  • Collagen – This protein, found only in animals, can only be made using oxygen. It allowed cells to stick together for the first time.
  • Sponges – These 650 million year old sponge fossils are thought to have been the first multi-cellular animals on Earth.
  • The Heron Island Research Centre – Here research scientists are studying the evolution of the earliest sponges.

The first complex animals

A boy from Attenborough’s own school discovered a 560 million year old fossil called Charnia, the first ever Precambrian fossil. Since that momentous discovery paleontologists have unearthed thousands of fossils from that ancient period.

  • Charnwood – The forest near Attenborough’s Leicestershire home where Charnia was discovered.
  • Charnia masoni – The fossil discovered by schoolboy Roger Mason.
  • New Walk Museum, Leicester – where the original Charnia fossil is now stored.
  • Charnia masoni and Charnia wardi – A scientific article about the discovery of other Charnia specimens.
  • Mistaken Point – One of the richest sources of  Precambrian (now called Ediacaran) fossils on Earth.
  • Fractal body plans – The animals of Mistaken Point grew their bodies through fractal branching, which allowed them to grow large bodies with very few genetic commands.

A giant leap in evolution

The fossils of animals of Flinders Ranges in Ediacara show evidence that 550 million years ago, animals had taken an evolutionary leap forward by moving for the first time and developing a new body plan, which almost all animals use to this day.

  • Flinders Ranges – A fossil site in South Australia, where many important Ediacaran fossils have been discovered and studied.
  • Trace fossils – The Ediacaran animals had no hard parts to be preserved, so we can only learn about them by studying imprint trace fossils (like footprints) they left behind.
  • Spriggina – The first animal with a bilaterally symmetrical bodyplan, where the left and right sides form a mirror image. Virtually all animals alive today, including us, use this body plan.
  • Kimberella – An early mollusc, the ancestor of snails, which fed on bacterial slime using a proboscis.
  • Funisia – The first fossil evidence of sexual reproduction in animals, discovered by Dr. Mary Droser.

An explosion in diversity

542 million years an event known as the Cambrian Explosion saw a burst of evolution never seen before or since. For the first time, predators appeared in the seas and prey animals evolved dramatic defences.

  • Markuelia – An ancient marine worm with the first signs of teeth and a gut.
  • Swiss Light Source – This stadium-sized particle accelerator allowed scientists to look inside fossilized Markuelia embryos for the first time.
  • The Burgess Shale – A fossil deposit high in the Rocky Mountains from where over 100,000 fossils of Cambrian animals have been discovered.
  • Charles Doolittle Walcott – The secretary  of the Smithsonian Institution who discovered the fossils of the Burgess Shale and went on to excavate Cambrian 65,000 fossils.
  • Opabinia – With five eyes and a long, grabbing proboscis,  it was like nothing that exists on Earth today.
  • Wiwaxia – An ancestral mollusc which protected itself from attack with heavy armour plates and long spines.
  • Anomalocaris – The first apex (top) predator on Earth, which snatched its prey using powerful appendages.
  • Mantis shrimp – A modern day predator with many similarities to Anomalocaris.
  • Hallucigenia – an armoured lobopod with seven pairs of legs and spines, which was first wrongly interpreted as walking on its spines.
  • Aysheaia – A lobopod worm which lived on and fed on sponges.
  • Pikaia – A small worm-like creature with a thin gristly rod running the length of its body, which is thought to be the ancestor of all back-boned animals.

Rise of the arthropods

During the Cambrian period a new group of animals emerged which would conquer the seas and make the first pioneering steps onto land.  They had external skeletons known as exoskeletons and jointed limbs.

  • Trilobites – These marine arthropods lasted almost 300 million years on Earth and were the most successful animals of all time, outlasting even the dinosaurs. Over 50,000 species have been discovered.
  • Pneumodesmus newmani – The first known air-breathing animal, which resembled a millipede and lived 428 million years ago.
  • Jaekelopterus –This 2.5m sea scorpion, the largest arthropod of all time, was a monster of the seas.
  • Crail beach This beach in Scotland is famous for its fossils from the Carboniferous period,  including several sets of fossilized trackways created by a giant millipede-like creature called  Arthropleura.
  • Meganeura – With a wingspan of around 3ft, this giant dragonfly-like insect was the largest flying insect of all time.

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