by the shore First stop on our aquatic adventure is the seashore which is what we call areas of land that are right next to the ocean There are many different kinds of shore from sandy or rocky beaches to ocean cliffs and caves and each one is teeming with life These shorelines have their own ecosystems that are unique to the edge of the watery world they connect with WHAT IS SAND Sand is made of rocks or seashells that have been broken down into tiny pieces by the movement of waves You can see this in action if you find a stone or pebble on the beach it will most likely be round and smooth because it has been worn down by rubbing over other pebbles over and over again as the waves come in and out LUGWORM CRAB RAZOR CLAM LIFE UNDER THE ROCKS When you’re at the beach look under a few rocks or dig into the sand to see what’s living there Creatures like crabs clams and worms might hide under rocks or burrow into sand to escape predators like birds In fact the sand under your toes is home to thousands of organisms some so microscopic you can’t even see them MUSSELS ROCKWEED SEA LETTUCE STARFISH SEA URCHIN ANEMONE BARNACLES LIMPETS FIDDLER CRAB RED CRAB HERMIT CRAB 10 TIDE POOLS Every day at different times the tide comes in and out in and out At high tide this whole area is underwater At low tide the water is low enough for us to see lots of creatures and seaweed Sea lettuce to small fish crabs mussels eels or even octopuses are trapped in pools of seawater by rocks and sand A lot of these creatures are quick and good at hiding but with a little patience you never know what you might see
POUNDING WAVES Ocean waves can carry a huge amount of energy and over time their pounding wears away at solid rock This can erode the shoreline causing it to disappear and fall into the ocean This pounding can make cool tunnels called arches and columns of rock called stacks ARCH CELESTIAL PULL We are kept on the ground because the gravity of Earth pulls us down toward it The Sun and Moon also have strong gravitational pulls which cause the ocean to move toward them This makes the tide high when the Moon or Sun is overhead but low when they are farther away High tide Low tide STACK Full moon New moon Low tide High tide DID YOU KNOW Most of the beautiful white sand in Hawaii is actually parrotfish poop They grind dead coral with their super-strong teeth and then pass it through their bodies Depending on the species one parrotfish can produce between 880 pounds to 4 5 tons of sand a year PARROTFISH This is all very cool but where did all this water come from What a fantastic question Gilbert I’ll explain 11
forming oceans We might be standing on solid ground but did you know that our planet has more water than land In fact over 70 percent of our Earth is covered by ocean Not only is the ocean huge but it’s also very old To see where all this water came from we need to go back in time about 4 6 billion years to when Earth was just starting to form out of clouds of dust swirling around the sun COOLING DOWN As Earth formed it became very hot causing the water within it to erupt as water vapor from volcanoes then condense or fall as rain covering the whole planet Some water also probably came from icy comets colliding with the early Earth A HOT ROCK Earth was created when rocks dust and metal collided Within all these materials were minerals that contained water FROM WATER TO LAND About 375 million years ago as the ocean teemed with a huge variety of life some animals that lived close to land evolved to breathe air and moved to live on the land permanently Some then decided to move back to the ocean In fact whales and dolphins evolved from a land mammal EARTH 4 6 BILLION YEARS AGO LIFE IN THE OCEAN Some scientists believe that around four billion years ago the very first life on Earth began somewhere in the ocean deep down near hydrothermal vents Over the next few billion years this tiny and simple microscopic life got more complicated as it developed 12
BROKEN CRUSTS Other land masses grew and joined together due to the movement of sections of Earth’s crust called tectonic plates Below is what Earth looked like around 200 million years ago EARTH NOW EARTH’S PLATES The molten rock in Earth’s mantle is so hot it moves and flows like molasses causing the tectonic plates on top of it to move around Where these plates collide some land is pushed downward while other land is pushed upward This movement has changed the face of the Earth drastically over millions of years LAND AND SEA Around 4 billion years ago the entire Earth may have been covered in water without any land at all Later volcanoes grew out of the ocean and formed the first land masses The mantle is mostly solid rock but parts of it are hotter and more fluid The outer core is made up of liquid rock and metal The inner core is solid rock made up of iron and nickel Earth’s crust is the thinnest layer and is divided into two types continental and oceanic SET IN STONE The reason we know so much about creatures that lived millions of years ago is because of fossils When an animal in the ocean dies it can become buried in dirt and clay at the bottom of the ocean Over millions of years these bodies and bones get turned into rock making a fossil We can find these fossils in the ground and study them to find out what animals from millions of years ago were like Professor how can we find out more about the ocean Well I’ve got a ship moored nearby Let’s climb aboard 13
