Bio Chapter 19 – Flashcards
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Extinct Species
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species who have no living members in existence anymore but due to fossils, we know that they once lived
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Relative Dating
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allows paleontologists to determine whether a fossil is older or younger than other fossils, does not tell the age of the fossil
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Radiometric Dating
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uses the proportion of radioactive to nonreactive isotopes to calculate the age of a sample
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Trace Fossils
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provide us with indirect evidence of life in the past, such as the footprints, tracks, burrows, borings, and feces left behind by animals.
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Index Fossil
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distinctive fossil that is used to compare the relative ages of fossils
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Era
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major division of geologic time; usually divided into two or more periods
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Half Life
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length of time required for half of the radioactive atoms in a sample to decay, it helps geologists determine the age of rocks and fossils
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Geologic Time Scale
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a system of chronological measurement that relates stratigraphy to time, and is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships between events that have occurred throughout Earth's history
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Period
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division of geologic time into which eras are subdivided
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Plate Tectonics
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geologic processes, such as continental drift, volcanoes, and earthquakes, resulting from plate movement
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Permian Period
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last period of the paleozoic era, occurred from 299 to 251 million years ago
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Cretaceous Period
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the last of the three periods of the Mesozoic Era, occurred 146 to 66 million years
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From the fossil record, paleontologists learn about the structure of ancient organisms, their environment, and the ways in which they lived.
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What do fossils reveal about ancient life?
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Relative dating allows paleontologists to determine whether a fossil is older or younger than other fossils. Radiometric dating uses the proportion of radioactive to stable isotopes to calculate the age of a sample.
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How do we date events in Earth's history?
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The geologic time scale is based on both relative and absolute dating. The major divisions of the geologic time scale are eons, eras, and periods.
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How was the geologic time scale established, and what are its major divisions?
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Building mountains, opening coastlines, changing climates, and geological forces have altered habits of living organisms repeatedly throughout Earth history. The actions of living organisms over time have changed conditions in the land, water, and atmosphere of planet Earth.
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How have our planet's environment and living things affected each other to shape the history of life on Earth?
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Paleontologists learn about the structure of ancient organisms, their environment, and the ways in which they lived.
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What can a paleontologists learn from fossils?
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Some soft bodied organisms decay too quickly.
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Why have so few organisms become fossilized?
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Relative dating and radiometric dating
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What are two ways in which geologists determine the age of fossils?
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Eras are subdivided into periods
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How are eras and periods related?
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Plate tectonics, which are movements of plates over Earth's mantle. Building mountains and changing climates. Collisions of giant asteroid tossed up dust and blocked the sun's energy changing the atmosphere.
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Describe three processes that have affected the history of life on earth.
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Continental drift has caused mountains to build and climates to change. Species were spread out and more distributed when landmass's collided and mountain ranges rose.
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Describe two ways in which continental drift has affected organisms.
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Macroevolutionary patterns
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changes in anatomy, phylogeny, ecology, and behavior that take place in clades larger than a single species
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Cladograms
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diagram depicting patterns of shared characteristics among species
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Background extinction
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extinction caused by slow and steady process of natural selection
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Mass extinction
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event during which many species become extinct during a relatively short period of time
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Gradualism
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the evolution of a species by gradual accumulation of small genetic changes over long periods of time
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Punctuated Equilibrium
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pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
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Adaptive Radiation
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process by which a single species or a small group of species evolves into several different forms that live in different ways
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Convergent Evolution
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process by which unrelated organisms independently evolve similarities when adapting to similar environments
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Coevolution
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process by which two species evolve in response to changes in each other over time
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Flowers and Pollinators, Plants and Herbivorous Insects
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Two examples of coevolution
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If the rate of speciation in a clade is equal to or greater than the rate of extinction, the clade will continue to exist. If the rate of extinction in a clade is greater than the rate of speciation, the clade will eventually become extinct.
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What processes influence whether species and clades survive or become extinct?
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Evidence shows that evolution has often proceeded at different rates for different organisms at different times over the long history of life on Earth.
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How fast does evolution take place?
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Two important patterns of macroevolution are adaptive radiation and convergent evolution.
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What are two patterns of macroevolution?
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The relationship between two coevolving organisms often becomes so specific that neither organism can survive without the other. Thus an evolutionary change in one organism is usually followed by a change in the other organism.
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What evolutionary characteristics are typical of coevolving species?
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If there is variation, the chance of surviving environmental changes increases.
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How does variation within a clade affect the Clade's chance of surviving environmental change?
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Mass extinction represents the disappearance of an entire ecosystem. On the other hand, background extinction is gradual and not as much is wiped out as quickly.
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How is mass extinction different from background extinction?
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Gradualism suggest that evolution occurs slow and steady, whereas punctuated equilibrium is brief periods of more rapid change
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Explain how punctuated equilibrium is different from gradualism?
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It would speed up because genetic changes spread more quickly among fewer individuals
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Why would evolution speed up when a small group of organisms migrates to a new environment?
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If two species occupy the same niche and evolve similar structures
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When might adaptive radiation result in convergent evolution?
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Similar environments exert similar pressures on different species and may result in adaptations of structures to perform similar functions.
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What role does the environment play in coevolution?
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In convergent evolution, two different organisms evolve independently and adapt similar structures to fit their needs. In coevolution, the organisms evolve in response to the needs of one another.
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Compare and contrast convergent evolution and coevolution.
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It results in the formation of a new species
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What does "speciation" result in?
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the dying out of a species and a reduction of biodiversity
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What does extinction result in?
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They died out if they could not adapt
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Evidence indicates that before the Permian extinction the oceans lost most of their oxygen. What effect do you think the loss of oxygen had on most organisms?
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Geological change is slow and steady.
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Why did Darwin think evolution was a gradual process?
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Their structure does not change much over time since the beginning of the fossil record
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Why are horseshoe crabs an example of a species in a state of equilibrium?
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When a small group of organisms migrate somewhere overtime, could take place after a massive extinction, after the population is isolated.
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When might rapid evolution take place?
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Earth's early atmosphere contained little or no oxygen. It was principally composed of carbon dioxide, water vapor, and nitrogen, with lesser amounts of carbon monoxide, hydrogen sulfide, and hydrogen cyanide
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What do scientists hypothesize about early Earth and the origin of life?
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Endosymbiotic
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What theory explains the origin of eukaryotic cells?
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The development of sexual reproduction increases genetic variation.
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What is the evolutionary significance of sexual reproduction?
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Violent volcanic activity shook Earth's crust. The Earth then cooled enough to allow solid rocks to form and rain to fall.
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What happened during earth's early history?
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They filled a sterile flask with water, to simulate the oceans, and boiled it. To the water vapor, they added methane, ammonia, and hydrogen, to simulate what they thought had been the composition of Earth's early atmosphere. They passed gases through electrodes, to simulate lightning. Next, they passed the gases through a condensation chamber, where cold water cooled them, causing drops to form.
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How did Miller & Urey model conditions that existed on early earth in their experiment?
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They seeked to answer the question: Could organic molecules assemble under conditions on early Earth?
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What question did Miller & Urey's experiment seek to answer?
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21 Amino Acids
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What were the results of their experiment?
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RNA stores information in its nucleotide sequence
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How would RNA have stored genetic information?
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The bacteria formulated into organelles, making the cells more complex
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How did ancient anaerobic prokaryotes benefit from a symbiotic relationship with bacteria?
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The bacteria had greater protection from the surrounding cell.
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How did bacteria benefit from the relationship?
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Early multicellular organisms underwent a series of adaptive radiations, resulting in great diversity. When eukaryotes reproduce sexually, offspring receive genetic material from two parents. Meiosis and fertilization shuffle and reshuffle genes, generating lots of genetic diversity.
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How did the development of sexual reproduction impact the amount of genetic variations in populations?
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The development of sexual reproduction sped up evolutionary change because sexual reproduction increases genetic variation.
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How is the pace of evolution affected by an increase in genetic variation?
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No, because the same conditions no longer exist on Earth
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Could life arise from non life today? Why or why not?
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From endosymbiotic prokaryotes (that were able to use oxygen to generate energy-rich ATP)
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According to the endosymbiotic theory, how did mitochondria evolve?
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Mitochondria contain DNA similar to bacterial DNA. Mitochondria have ribosomes similar to bacteria. Mitochondria, like bacteria, reproduce by binary fission
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What evidence supports the endosymbiotic theory?
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Because it increases genetic variation
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Why is the development of sexual reproduction so important in the history of life?
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1. Development of photosynthesis 2. Free oxygen in the air 3. Development of eukaryotic cells 4. Sexual reproduction
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Put the following events in the order in which they occurred: sexual reproduction, development of eukaryotic cells, free oxygen in the atmosphere, and development of photosynthesis.
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Cretaceous, Jurassic, Triassic
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What 3 periods are part of the Mesozoic era?
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Jurassic
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During which period did Archaeopteryx evolve?
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Archaeopteryx
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the oldest known fossil bird, of the late Jurassic period. It had feathers, wings, and hollow bones like a bird, but teeth, a bony tail, and legs like a small coelurosaur dinosaur.
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Triassic
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During which period did the first dinosaurs evolve?
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late Triassic
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During which period did the first mammals evolve?
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Cretaceous
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During which period did flowering plants evolve?
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Sixty-five million years ago, more than three-fourths of all plant and animal species living on Earth became extinct. This event is known as the K-T mass extinction because it occurred at the boundary between the Cretaceous (K) and Tertiary (T) time periods. The most famous group of animals to perish was the dinosaurs
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K-T Extinction
