Early Earth 4.6 Billion •The Earth formed about ________________ years ago. Oxygen •There was little ________________. •Scientists have found fossils of ___________________ in Bacteria 3.5 Billion rock that formed __________________ years.
Download ReportTranscript Early Earth 4.6 Billion •The Earth formed about ________________ years ago. Oxygen •There was little ________________. •Scientists have found fossils of ___________________ in Bacteria 3.5 Billion rock that formed __________________ years.
Early Earth 4.6 Billion •The Earth formed about ________________ years ago. Oxygen •There was little ________________. •Scientists have found fossils of ___________________ in Bacteria 3.5 Billion rock that formed __________________ years ago = first life!!!! 2.5 Billion •About ______________________ years ago, organisms began using sunlight energy to _____________________= ___________________ make their own food Photosynthesis •In this way, ______________built up in Earth’s Oxygen atmosphere The Cambrian Period – 544-505 million years ago Animals of the Cambrian Period: Paleozoic At the beginning of the ___________Era (544 million years ago) life took a great leap forward as many different kinds of organisms evolved. For the first time, organisms had hard parts and outer skeletons. At this time, all animals lived in _____________. the sea Invertebrates like jellyfish, worms, and sponges drifted through the water, crawled along the sandy bottom, or attached themselves to the ocean floors. The sudden diversity of life forms from this time is now referred to Cambrian ___________. Explosion as the _________ Many of these organisms left fossils: Trilobites Hemirhodon Even today, we can easily recognize modern species which resemble these ancient life forms: The Ordovician Period – 505-438 million years ago By the time of the Ordovician Period, warm, shallow seas cover much of the Earth, invertebrates (animals with no backbone) dominate the seas, and early vertebrates (jawless fishes) become common. Ordovician Animals The Silurian Period – 438-408 million years ago During the Silurian Period, land plants appear, along with insects and spiders. This period marks the invasion of land by fairly vertebrates complex life forms. There are still no _______________ on land! The Devonian Period – 408-360 million years ago vertebrates During the Devonian, ___________invade the land! The first to do so were lungfish ________with very basic forelimbs. Their motivation probably included the availability of prey and escape from predators ________________________________________. amphibians Eventually, some of these species would evolve into the first ____________ (animals that spend some of their time in water, and some of their time out of water – i.e. frogs and salamanders). vertebrates These are the common ancestors of all land-dwelling ____________ . On land, they would have encountered the first plants that could survive in drier areas – including the first ______. ferns In the oceans, the Devonian was known as the age of the fishes, as every main group of fishes had evolved. Most fishes now had jaws, bony skeletons, and scales on their bodies. Sharks appeared late in the Devonian Period. The Carboniferous Period – 360-286 million years ago During the Carboniferous period (the longest of the Paleozoic era), giant ferns and cone-bearing plants and trees formed vast, Coal Forests swampy forests called “______________”. These are named for the fact that their remains formed thick deposits of sediment that changed into Coal _____over millions of years. This is the primary __________ Fossil Fuel used on Earth today. The lights, heating, and air conditioning in your house today are running on the energy stored in this coal. It took over 200 million years to create the fuel that we burn in an instant today. Where does that carbon go next? Into the air in the form of carbon dioxide and carbon monoxide waste – contributing to the greenhouse effect and global warming! During the carboniferous, __________evolved into many forms, including insects HUGE ____________and cockroaches dragonflies Reptiles evolved from amphibians during the carboniferous period. This involved adaptations such as _____ dry skin and tough, leathery ______. eggs The Permian Period – 286-245 million years ago During the Permian period, the super-continent Pangaea forms as Earth’s continents moved together, and then began to break apart again. Huge climate changes occurred. Land near the south pole was covered in ice, while deserts expanded into the tropics. During the Permian period, reptiles become dominant on land, and the first warm-blooded reptiles (ancestors of the mammals) appear. The end of the Permian period must have been one of the most horrible times in Earth’s history to be alive. 90% of Earth’s species were wiped out as climate change, warming oceans, volcanic eruptions, and spikes in atmospheric carbon dioxide marked one of the worst mass extinctions in Earth’s history!!! The Triassic Period – 245-208 million years ago Some living things survived the Permian mass extinction. These became the main forms of life in the early Triassic, the first period Mesozoic of the _____________era. Among them were fish, insects, conebearing plants, and several lines of reptiles. Much of Pangaea holds together for most of the Triassic period as the middle of the super-continent becomes hot and dry. The age of the reptiles begins in the Triassic period. Among the reptiles are the first turtles, crocodiles, and most famously, the dinosaurs. mammals warm The first ____________evolve from ______-blooded reptiles fur and during the Triassic period. Adaptations such as ___, live young birthing and caring for _________enable warm-blooded habitats animals to inhabit a broader variety of ________. Still, small stay out of sight, and mammals remain ______, reproduce quickly in order to survive in a landscape ___________ dinosaurs dominated by the ____________. The Jurassic Period – 208-144 million years ago dinosaurs During the Jurassic period, _________became the dominant animal Pangaea on land. __________continued to break apart as North America South America Africa separated from ______ _________and ________. Sea levels rose in many parts of the world. Dinosaurs “ruled” Earth for about ______million years. At 20 meters (over 70 150 feet) long, Dicraeosaurus was among the largest, while Compsognathus (50 centimeters) was among the smallest. birds Earth saw the first ______during this time, one of which was Archaeopteryx. It’s name means “ancient winged thing”. Its fossils show well-defined feathers, which are most likely adapted from the _______of scales its reptilian ancestors. skulls Fossils of species with the ________and teeth of dinosaurs, but the beaks _______and bodies of birds, suggest that birds descended from small dinosaurs which evolved lighter (hollow) bones, finer scales (feathers), and arms and fingers adapted to leaping and short flight. The Cretaceous Period – 144-65 million years ago Reptiles __________continued to dominate throughout the Cretaceous period. flight ________continued to develop in both dinosaurs and newly evolved bird competed species - these species __________for space in the skies. The contest birds hollow was won by the _______, whose feathers and _________ bones were better adapted to flight than were the bodies of dinosaurs. Mammals continued to evolve throughout the Cretaceous period, small and mostly ___________. nocturnal though they remained _______ New flowering plants forms of plants were evolving, including the first __________ insects and produced _______ seeds inside which were pollinated by ________ fruit, which could be transported by plant-eating organisms. Still, the dinosaurs ruled the Cretaceous period. Many were now enormous, carnivorous predators like Tyrannosaurus Rex. 65 million years ago, another At the close of the Cretaceous period, about ____ mass extinction wiped out half of all plant and animal groups. It was likely caused when a massive asteroid collided with the Earth, throwing huge sunlight amounts of dust and water vapor into the atmosphere, blocking _________ around the world for years. plants (Earth’s primary producers) died out, and the food Without sunlight, ________ herbivores chain collapsed, bringing down _____________ and their predators in the aftermath. No dinosaurs _________survived. This is now referred to as The KT ___Event . The Tertiary Period – 65-1.6 million years ago Mammals Paleontologists call the Cenozoic “The Age of ___________”. During the Mesozoic, mammals had a hard time competing with the dinosaurs for food and places to live. The extinction of the dinosaurs ___________created an opportunity for mammals, which evolved adaptations that allowed them to live in many different environments – on land, in water, and even in the air! During the Tertiary period, Earth’s climates were generally warm mild ________and _______. The continents were moving nearer to their present-day locations. In the oceans, many types of mollusks appeared. Marine mammals such as _______and whales _________ dolphins evolved from land mammals that had begun to venture back into the oceans to pursue food sources and escape from increasing land predators. flowering insects On land, _________plants and __________flourished, as each adapted to play a part in the evolution of the other. Flowering plants developed the production of glucose-based nectar, which was a favorite food source of insects. In turn, insects provided flowering plants with a way to transport their sex cells to one another over long distances. As grasses evolved, they provided a food source for grazing mammals (these are the ancestors of today’s deer, sheep, cattle, and other grazing mammals). These, in turn, provided a food source for larger and larger predatory mammals. The Quaternary Period – 1.6 million years ago - Present The mammals that had evolved during the Tertiary period faced a changing climate in the Quaternary period which ice ages involved several ____ ______. Among these mammals humans were the ancestors of ________. The oldest fossils of human ancestors (Australopithecus afarensis) date back to 3.5 million years ago. about ____ Fossils from 3.0 to 2.3 million years ago include those of Australopithecus africanus and Australopithecus aethiopicus. A. africanus fossils have been uncovered largely in South Africa. The bone structure of the face and jaw indicates a diet of mostly seeds, nuts, fruits, and tubers. A. aethiopicus fossils are found in East Africa. The larger bones in the face and jaw indicate that these hominids ate hard, gritty foods that required extremely heavy chewing. Both species were smaller in stature than modern humans, with smaller brains, relatively longer arms, and more curved finger bones. A. africanus A. aethiopicus Going back about 2 million years, we find fossils of several hominid species which existed simultaneously, likely representing several branches of early human evolution – each one selected for by the specific environment in which it lived. Homo habilis The diet of ____________ may have included meat. Australopithecus boisei also had extremely strong facial bones and __________________ muscles, despite being a little over four feet tall. Australopithecus robustus was also probably a meat eater. ___________________ By one million years ago, all these species were extinct!!!!!!!!!!! Homo habilis Australopithecus Boisei A. robustus One million years ago, the fossil record reveals the existence of Homo erectus. There is so much variation among this group that some consider it to consist of several species: Homo ergaster in Africa, Homo erectus in Asia, and Homo antecessor in Europe. Brain size in increasing at this time and these groups are adapting to life in various environments, from warm savannas to cold, temperate forests. Their diet was generalized, including meat. Their anatomy included modern arms and hands, an elongated spine, and long legs. These were fully bipedal (uprightwalking) hominids! The exact lines of descent between early hominid species is debated, but the relationships among more modern species are easier to piece together. Homo heidelbergensis existed from 600,000 to 100,000 years ago and gave rise to both Homo neanderthalensis and Homo sapiens. Homo heidelbergensis Within the last 100,000 years, Homo neanderthalensis and Homo sapiens coexisted and even interacted with each other. Today, neanderthalensis is extinct, while Homo sapiens are sitting in the desks all around you!!! Skulls of Homo neanderthalensis (left) and Homo sapiens (right). Notice the relative sizes of the faces and cranial cavities. Can you tell which was more muscle and which was more mind?