Chapter 25 Notes
Chapter 25 Notes Life103
Popular in Biology of Organisms-Animals and Plants
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This 6 page Class Notes was uploaded by Courtney Potter on Sunday August 30, 2015. The Class Notes belongs to Life103 at Colorado State University taught by Shane Kanatous; Graham Peers in Summer 2015. Since its upload, it has received 56 views. For similar materials see Biology of Organisms-Animals and Plants in Entomology at Colorado State University.
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Date Created: 08/30/15
What Is Life Introduction Inanimate objects can control energy but not respond Example a table can grow counteract energy but cannot pass on genes Organisms change and convert energy to use and to fuel growth reproduction etc 0 Some can photosynthesize plants Organisms can vary on what they use as a primary food source carbs protein fat Most animals suck at converting plant material into energy unless they have good relationships with bacteria Animals take in oxygen and produce carbon dioxide re ection of metabolism Key Factors of Life 1 Homeostasis Ability to regulate internal systems separate from external environment 2 Organization Cells tissues organ organ systems organisms Oxygen is the nal electron acceptor in the Electron Transport Chain to create ATP 0 Anaerobicsprinting short term things that happen too fast to need oxygen form lactic acid 0 Aerobic needs oxygen Growth 0 from cells to organism Adaptation o a trait that has a functional role that is maintained and evolved by natural selection Response To Stimuli 0 ght or ight Reproduction Classi cation of Species Domain 1 Bacteria 2 Archaea a Prokaryotic organisms adapted to extreme environments 3 Eukarya all need symbiotic relationships with bacteria Plantae Fungi Animalia Protists goom Kingdom Phylum Class Order Family Genus Species o Reproductiver isolated parents can reproduce with same species or different but young will NOT be fertile if parents reproduce with another species FossHs Found in sedimentary rock strata amber and ice 0 Radiometric dating parent isotopes decay to daughter isotopes at a speci c rate varying from different isomers called their half life 0 Fossils contain different isotopes when they die one stops producing while the other decays these are compared to date fossils works better on younger ones 0 Old fossils age can be determined by comparing age of volcanic rock around them CHAPTER 25 HISTORY OF LIFE ON EARTH Geologic Time Scaletime scale dividing Earth s history into four eons The Hadean Eon Big Bang Theory 0 Earth formed 4600000000 years ago from rock and dust around sun then hit with chunks of ice and rock 0 OparinHaldane Hypothesis 0 Earth was a reducing atmosphere contains hydrogen carbon dioxide hydrogen sul de 0 Stanley Miller tested hypothesis and found that amino acids could be produced in that atmosphere 0 MillerValley Experiments produced organic compounds in a neutral atmosphere also 0 Most likely life started by Alkaline vents where the pH is 911 and warm NOT in hydrothermal vents Conditions Facilitating Origins of Life 1 Nonliving abiotic production of building blocks amino acids and nitrogenous bases 2 Formation of building blocks into macromolecules proteins and nucleic acids 3 Packaged into protocells a Membranes packaging lipids that also have and maintain their own internal chemistry 4 Begin to Self Replicate a Self assemble but grow faster when attached to clay Vesicles or uid lled areas enclosed by membrane form 0 Can reproduce Metabolize and keep homeostasis 0 Form by lipids introduced in water hydrophobic tails form a lipid bHayer 0 Form external metabolism RNA is in rst life form instead of DNA 0 Ribozymes can make RNA if supplied with nucleotides 0 Pass on genetics by replicating and producing protocells The Archaean Eon o Prokaryote unicellular organisms containing a capsule cell wall plasma membrane cytoplasm and agella but no membrane bound organelles Stromatoliteslayered rocks forming by prokaryotes binding thin lms of sediment 0 Found in shallow marine bays Cyanobacteria s ancestor begins to photosynthesize 0 Oxygen reacts with water forming iron oxide sediment oxygen dissolves into water and saturates it then an atmosphere begins to form 0 Oxygen revolution leads to rst major extinction 90 of all anaerobic organisms die oxygen is toxic to them Proterozoic Eon Edicarian Era Single celled eukaryotes 0 Had cytoplasmic membrane endoplasmic reticulum ribosomes nucleus nucleolus nuclear membrane golgi apparatus mitochondria andor chloroplast o Endosymbiont Theorymitochondria and chloroplasts were once small prokaryotes living in larger cells not all eukaryotes have chloroplasts Support for Theory 1 Inner membranes have enzymes and transport systems similar to prokaryotes 2 Replicate by splitting process similar to prokaryotes circular DNA without histones or proteins 3 Have cellular machinery to translate and transcribe DNA 4 Size RNA sequence and sensitivity similar to prokaryotic ribosomes Multicellular Eukaryotes 0 Evolution of eukaryotic cells allowed for greater range of unicellular forms 0 Second wave of diversity occurred when multicellularity evolved giving rise to algae plants fungi and animals 0 Multicellular Organisms o Algae form 1200000000 years ago 0 Edicarian biota assemble larger more diverse soft bodied organisms that lived 535000000600000000 years ago life started in water because it s a more stable environment hard to heat organisms need water to live and none had developed mucus coating of skin to survive terrestrial life yet Phanerozoic Eon Paleozoic Era Cambrian Explosion 535000000525000000 years ago over 10 million years sponges cnidarians and molluscs o Predators begin to make rst appearance Ordovician 450000000 colonization of land by fungi plants and arthropods Devonian 365000000 tetrapods begin to appear 0 Includes amphibians reptiles and mammals o Mammals evolved and have lowerjaw with one bone malleus incus and stapes and different teeth types 0 Permian Extinction 251000000 0 96 of marine species extinct and 827 orders of insects destroyed o 16 million kilometers covered by lava raised temperature 6 degrees Celsius led to ocean acidi cation anaerobic bacteria thrives aerobic organisms decline Pangaeasupercontinent 250000000 years ago destroyed much ocean habitat by making basins deeper o Promotes allopatric speciationgeographic speciation as populations became isolated from each other preventing genetic swapping Mesozoic Era Cretaceous Extinction 65000000 years ago wiped out half of marine species most land animals and plants all dinosaurs except birds 0 Happened by asteroid or comet o Takes 510 million years to recover diversity after mass ex nc ons Cenozoic Era Humans diverge from monkeys 6000000 years ago Evolutional Change Microevoution evolving above the species level 0 Example mass extinction affecting biodiversity and key adaptations through speciation Adaptive Radiation Evolutionary change over time which new species are formed with adaptations to ll different niches 0 Regional new organisms nd a new habitat and face little competition 0 65500000 years ago mammals began to diversify and grow to ll roles left behind by dinosaurs Rise of photosynthetic prokaryotes evolution of large predators Cambrian colonization of land all led to adaptive radiation Changes In Genes And Body 0 Heterochronyevolutional change in timing of developmental events 0 Examples loss of hind limbs in whales due to slow growth creation of wings in bats by accelerated nger growth Paedomorphosisreproductive organs grow faster than other organs causing juvenile body types with reproductive capabilities Homeotic genes regulatory genes that determine where things grow 0 Changes in nucleotide sequences in developmental genes affect function of the gene 0 Regulation of gene expression can cause evolutionary changes also Evolution Is NOT Goal Oriented 0 Darwin Descent and Modi cationcompex structures develop over time from ancestral structures
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