Titano Evolution (Ny) PDF

# EVOLUTION ## Fossils Tell a Story - How is it possible to find fossils of animals that lived in a tropical climate in Gotland? Take the example of a coral fossil shown in the picture. - What have fossils taught us about life? - A lot of research is dedicated to finding traces of life on other p...

# EVOLUTION ## Fossils Tell a Story - How is it possible to find fossils of animals that lived in a tropical climate in Gotland? Take the example of a coral fossil shown in the picture. - What have fossils taught us about life? - A lot of research is dedicated to finding traces of life on other planets than Earth. Do you think that's important research? ## Fossils Tell About The Past - Sand, clay and other small particles from land are constantly transported to the sea by rivers and wind. In the sea, the particles sink to the bottom and are deposited. Many seaweeds and animals also end up there when they die. - In some places, such as near coral reefs, shells and skeletons of animals dominate the seabed. - Over millions of years, a lot of material accumulates on the seabed. - This can compress the lowermost particles into rocks. Sandstone and shale are formed from sand and mud, respectively. When the seabed is dominated by calcium shells and skeletons, limestone forms. These rock types are called sedimentary rocks because they are formed by depositing loose sediment. - Fossils are found in sedimentary rocks. They are petrified remains of dead plants and animals that were once embedded in sediment. - Only hard parts like shells and skeletons can solidify into fossils. - You can also find land plants and animals as fossils. These may be the remains of plants and animals buried in swamps or lakes, which were later covered by sediment over a long time. ## The Continents Are Drifting - Continents on Earth are constantly changing position and form. - The movement is caused by currents in the molten rock beneath the solid earth's crust. - The collision of continents causes the crust to compress, resulting in the formation of mountains. This process can also bring up seabed rock to form mountains. - This is why marine fossils are found on land. ## Determining The Age Of A Fossil - Sometimes it is possible to determine the age of a fossil by measuring the amount of certain radioactive elements it contains. - Scientists also use fossils of known age to find out how old other fossils are. - Fossils discovered next to each other or in the same layer of rock are the same age. In the same way, fossils found lower down in a cliff are older than fossils found higher up. The sedimentary rocks form layer by layer from top to bottom. ## Evolution - Fossils tell us that life on Earth has evolved and changed over time, had we travelled back 100 million years ago, we would see different plant and animal species. - The evolution of living beings is called evolution. This process never ends. No one knows what characteristics plants and animals will have in the future. ## The History Of Life - Scientists who study the structure and history of Earth are called geologists. Geologists divide the time that Earth has existed into eons, eras, and periods. - The first three eons are often grouped together and are called the Precambrian. This period started with Earth’s formation, 4600 million years ago, and lasted until the Cambrian Period, about 600 million years ago. - The timeline shows some of the most important developments during the Precambrian. During these 4 billion years, life arose on Earth, but it was only tiny bacteria and archaea for a long time. - **Earth forms:** Earth is 4.6 billion years old. Initially, it was a glowing hot ball, but the surface gradually cooled and solidified into a crust. The Earth’s interior is still very hot (about 4000 degrees Celsius). - **The first life:** How or when life arose on Earth is unknown. One possibility is that cells came from outer space, carried by meteorites. Most scientists believe that life arose on Earth. There are fossils of bacteria dating back 3.5 billion years. Therefore, the first organisms may have formed 4 billion years ago, resembling bacteria. - **Water from comets:** About 4 billion years ago, the Solar System was quite chaotic. Comets bombarded Earth, and they contained a lot of water in the form of ice. Some calculations even suggest that all the water on Earth may have come from comets. - **Formation of oxygen:** About 3 billion years ago, cyanobacteria appeared. Like plants, they used sunlight as an energy source for photosynthesis. Their photosynthesis led to the formation of oxygen in the atmosphere . <start_of_image>- **Cells with a nucleus :** About 2 billion years ago, there was enough oxygen for plants and animals to evolve. These were initially unicellular organisms. Unlike bacteria, they had a cell nucleus. - **Stromatolites:** Some of Earth’s oldest fossils are structures called stromatolites, built by bacteria. - **Multicellular plants and animals:** About 1 billion years ago, unicellular organisms began to live in colonies. When the cells in a colony began to specialize in different tasks, the step towards multicellular organisms was not far. The first multicellular organisms probably appeared about 1 billion years ago. There were already worms and jellyfish in the Pre-Cambrian Period. ## The Last 600 Million Years - After the Precambrian, life on Earth evolved rapidly towards a variety of plants and animals. This was also the period when life moved onto land for the first time. - The timeline also shows that the time when humans have lived on Earth is very short compared to its 4.6 billion years of history. - ***Mass extinction:*** Life on Earth has been affected by several large-scale disasters, such as those that caused many groups of plants and animals to go extinct. The most recent extinction event occurred 66 million years ago, resulting in the extinction of dinosaurs. Many other species also went extinct. It is probably not only dinosaurs that vanished, but also 65% of all life on Earth. Scientists believe that a large asteroid measuring at least 1 km, hit Earth 66 million years ago. - ***The crater in Arizona:*** The crater in the Arizona desert, USA, formed by the impact of a 50-meter asteroid that crashed there about 50,000 years ago; despite its small size, it created a 1.2 km wide crater, indicating the immense force of such impacts. - ***66 million years ago:*** The asteroid that likely caused the mass extinction event was at least 10 km wide and struck Earth at a speed of 40,000 km/h. It probably crashed somewhere in the eastern part of Mexico. - ***600 million years ago:*** Molluscs, trilobites, and other animals with shells and hard exoskeletons are developing. This is why the amount of fossils increases from this period. Algae are the only multicellular plants. - ***500 million years ago:*** Corals, echinoderms, and cephalopods are common. Fish also appear, the first vertebrate animals with backbones. Land plants evolve. - ***400 million years ago:*** Insects appear. Amphibians evolved from fish, and they were the first vertebrates on land. Reptiles evolved from amphibians. Ferns become widespread. - ***Paleozoic Era:*** Insects evolve, and they become increasingly diverse. Amphibians evolve from fish, and they are the first vertebrates on land. Reptiles evolve from amphibians. Ferns dominate. The diversity of life on Earth increases incredibly. - ***66 million years ago (Kenozoic Era):*** Birds and mammals are prominent. The first primates evolve. Humans appear around 2 million years ago. ## How Evolution Works - The cheetah, a native of the African savannah, is the fastest land mammal. It can reach a speed of 100 km/h when hunting gazelles. This sprinter gets tired easily, so gazelles often escape if they can manage a small lead. - Not all gazelles are equally fast. The fastest gazelles have the best chance of survival, passing on this trait to the next generation. This selection leads to the evolution of ever-faster gazelles. - Cheetahs also benefit from speed; the most efficient hunters get the most food and are able to raise more young. - This ‘arms race’ between gazelles and cheetahs shows that they evolve to become faster over long periods. ## Variations Are Important - Sometimes, mutations occur. This means that a gene suddenly changes. This usually leads to a disease or other negative changes. For example, a gazelle might be unable to spot predators, or it might be poorly camouflaged. Slow gazelles are less likely to survive and reproduce, so these changes are not passed on. - But if a mutation gives a gazelle good camouflage or makes the gazelle faster, it will improve that gazelle’s chances of survival and reproduction. In this way, mutations affect gazelle development over time. ## Adaptation to the Environment - Imagine a moth that rests on tree trunks during the day. Tree trunks are often different shades because lichen grows on them. The moths are also mottled, and they successfully blend in with the tree trunks—an effective camouflage that helps them survive! - However, some moths might be born with darker wings. They will stand out more on light lichen-covered trunks and are easier prey for birds. - Now imagine that the environment changes: lichen disappears, and the trunks become dark. Then, the lighter moths stand out against the dark trunks, and the dark moths blend in perfectly. They are less likely to be eaten and pass on their dark color to their offspring. Eventually, most moths will be dark. - This type of selection, where organisms best adapted to their environment survive and reproduce, is called natural selection. ## The Formation of New Species - Imagine two groups of the same species, isolated from each other in different environments. Over long periods, they evolve to be so different that they can no longer interbreed even if they come together. In this way, one species can become two species. - Isolation can occur in many ways. For example, some individuals may end up on an island, where they form a new species. Mountain ranges can isolate different groups of animals, leading to speciation. ## Darwin Explained Evolution - In 1859, the English naturalist Charles Darwin published the book “On the Origin of Species,” which explained how species evolve and change, leading to new species. - The concept of evolution was controversial at the time because it challenged the religious view that all species were created separately by God. Darwin’s explanation, based on natural selection, was a revolutionary idea, but it is now the foundation of modern biological science. ## Galapagos Inspired Darwin - In his twenties, Charles Darwin sailed around the world on the HMS Beagle, studying natural history. He spent several weeks on the Galapagos Islands, 1000 km west of South America. - These islands are volcanic and formed relatively recently, which means any plants and animals currently on the islands must have migrated from other locations. - Darwin was surprised to see so many unique species on the Galapagos Islands. He observed that the 13 species of finches on the islands were very similar to each other but had a different beak structure. Each species had a diet best suited to its particular environment. - Darwin concluded that the original finch population had migrated to different islands, then adapted over time to different environments. This led him to the idea of natural selection driving the evolution of the finch species. ## Evolution in a Nutshell - Darwin's theory of evolution states that some members of a population are better suited to survival than others. The best-adapted individuals have a better chance of passing on their traits to the next generation. - This process explains the development of new species, which in turn contribute to the incredible diversity of life on Earth. - We can see how variation plays a crucial role in the evolution of species. The fittest individuals survive and reproduce, while those who are not well adapted to their environment struggle to live and reproduce. Over time, this process can lead to significant changes in the gene pool of a population. ## Life Beyond Earth - The Earth is located at a distance from the sun that allows for the existence of life as we know it. It is within the habitable zone or “Goldilocks zone.” - Even though Venus is closer to the sun, its surface temperature reaches 400 degrees Celsius, making it too hot for life as we know it. - Mars is closer to the habitable zone, although its average temperature is below -60 degrees Celsius. Despite evidence of past liquid water on Mars, the atmosphere is extremely thin, causing it to lack surface water. However, some researchers believe that bacteria might still survive on Mars. - The search for life elsewhere in the universe faces hurdles. - First, there are distances involved in traveling to other planets, and second, the time frame itself is a stumbling block. Our species has only existed for 300,000 years, a blink of an eye in the grand scheme of the universe. In order for extraterrestrial life to find us, they must exist and visit Earth during our relatively short period on Earth, which is a very improbable scenario in the vastness of the universe. <start_of_image> It’s important to remember that our understanding of life, and especially extraterrestrial life, is still developing. Every new discovery, every technological advancement offers us the potential to learn more, push back the boundaries of knowledge, and perhaps open our eyes to a universe teeming with new life forms beyond what we could ever imagine.