Presentation on theme: "The Big Bang Theory Many scientists believe that the Earth was formed at the same time as many other planets About 4.6 billion years ago After a massive."— Presentation transcript:
The Big Bang Theory Many scientists believe that the Earth was formed at the same time as many other planets About 4.6 billion years ago After a massive explosion, rock, dust, and ice began being pulled together by gravity forming the Earth
EARLY EARTH This artist’s illustration shows Earth shortly after the moon formed. Notice the rocky objects striking Earth from space, and the molten rock overflowing the surface.
Earth Origins FeatureEarly EarthLater Pre-Cambrian AtmosphereHelium and HydrogenN, CO 2, water vapor ContinentsNone (Earth was molten) Less dense material began to cool and form land masses known as continents OceansNone (too hot)As the surface cooled, water vapor began to condense to form rain. Gradually, rain water began to accumulate and form oceans
The Beginning of Life Scientists have found fossils of single- celled organisms Believed to have formed about 3.5 billion years ago Probably similar to present-day bacteria Scientists hypothesize that all other forms of life on Earth arose from these simple organisms Early organisms lived only in water
Life Moves on Land About 2.5 billion years ago, many organisms began using energy from the sun to make their own food Processes in the atmosphere changed some of this O 2 into a form called ozone (O 3 ) The atmosphere developed a layer rich in ozone that blocked out the deadly UV rays This allowed organisms to survive on land
Key Ideas and Vocabulary How do fossils form? How do fossils form? What are the different kinds of fossils? What are the different kinds of fossils? What does the fossil record tell about organisms and environments of the past? What does the fossil record tell about organisms and environments of the past? Terms fossil fossil sedimentary rock sedimentary rock mold mold cast cast petrified fossil petrified fossil carbon film carbon film trace fossil trace fossil paleontologist paleontologist scientific theory scientific theory evolution evolution extinct extinct
Fossil-the preserved remains or traces of living things
Fossils Fossils found in rock include: molds and casts petrified fossils carbon films and trace fossils Other fossils form when the remains of organisms are preserved in substances such as tar, amber, or ice.
Fossils Fossils are usually found in sedimentary rock They provide clues to the past sedimentary rock- type of rock that is made of hardened sediment Examples: sandstone, coal, limestone
Scientific Theory- well-tested concept that explains a wide range of observations Evolution- the process by which all the different kinds of living things have changed over time http://www.brainpop.com/science/ecolog yandbehavior/humanevolution/preview.w eml http://www.brainpop.com/science/ecolog yandbehavior/humanevolution/preview.w eml
Who was Charles Darwin? http://www.brainpop.com/science/famousscientists/charlesdarwin/preview.weml
Darwin’s Journey December 1831 at 22 years old, Darwin set sail on the British ship HMS Beagle Became the ship’s naturalist Studied plants, animals, and everything about the natural world Darwin’s most important observations: Diversity of living things Remains of ancient organisms Charcteristsics of organisms on the Galapagoes Islands
READ ONLY SLIDE Evolution Darwin reasoned that plants or animals that arrived on the Galápagos Islands faced conditions that were different from those on the mainland. Perhaps, Darwin hypothesized, the species gradually changed over many generations and became better adapted to the new conditions. The gradual change in a species over time is called evolution.evolution.
Evolution Evolution- The gradual change in a species over time Now that Darwin had a theory, he needed to find out how evolution worked A main component to his theory was natural selection
Natural Selection The process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species http://www.brainpop.com/science/ecolog yandbehavior/naturalselection/preview.w eml http://www.brainpop.com/science/ecolog yandbehavior/naturalselection/preview.w eml
Look at the drawing below of the bones in a crocodile’s leg. Compare this drawing to the previous slide. Do you think that crocodiles sahare a common ancestor with birds, dolphins, and dogs? Support your answer with evidence.