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114 Cards in this Set
- Front
- Back
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Seven characteristics of life |
1. Displays order 2. Harness and uses energy 3. Reproduces 4. Responds to stimuli 5. Exhibits homeostasis 6. Grows and develops 7. Evolves and adapts |
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Big bang occurred how long ago? Solar system began? Earth formed? |
1. 13.7 Billion years ago 2. 4.6 Billion years ago 3. 4.5 Billions years ago |
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How building blocks and cells formed |
1. Form nucleotides and amino acids 2. Nucleotides and amino acids (monomers) become polymerized 3. Polymers became enclosed in membranes 4. Membrane bound polymers acquire cellular properties |
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3 main theories to explain origin of first organic molecules |
1.Reducing Hypothesis 2. Extraterrestrial Hypothesis 3. Deep sea vent hypothesis |
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Reducing Hypothesis |
- Low O2 atmosphere is a reducing environment - allowing inorganic molecules to reduce to form organic |
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Extraterrestrial Hypothesis |
- some scientists believe that organic compounds came from asteroids and comets which produced "primordial soup" |
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Deep sea vent Hypothesis |
- Elements exit deep sea thermal vents at higj temperatures - organic compounds formed under cooling conditions |
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4 steps that ultimately formed cells |
1. Form nucleotides and amino acids 2. Nucleotides and amino acids (monomers) became polymerized. 3. Polymers become enclosed in membranes. 4. Membrane bound polymers acquire cellular properties. |
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Probionts |
- First non-living enclosed structures - Abiotic, contain organic molecules
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RNA |
- DNA first developed from RNA - RNA can perform 3 functions - store information - capacity for self-replication - capable of enzymatic activity |
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Hadean era |
Earth cooled, oceans began forming. |
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First prokaryotes |
- first organisms were anaerobic heterotrophs - 2. evolved into Anaerobic chemoautotrophs - 3. evolved into Anaerobic photoautotrophs
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Changes in earths atmosphere |
1st one - Unknown (light gasses escaped into space, i.e He, H2 2nd one - Made up of Methane, Nitrogen, Carbon dioxide, Water 3rd (current) one - Mostly Nitrogen, Oxygen, and Carbon Dioxide |
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Stromatolites |
- Microbially mediated layered structure - Generally found in hot or very salty environments - Can reach 1.5m high |
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How Heterotroph's obtain Energy/Carbon |
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Cyanobacteria |
- Occupied earth for at least 3.5 billion years - Dominant form of life on earth for 1.5 billion - Most ancient oxygenic photosynthesizer - First to produce chlorophyll a |
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Three domains of life |
Bacteria Archea Eukarya |
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Symbiotic/Endosymbiotic relationships |
Symbiotic relationships - 2 species living in direct contact and fuse
Endosymbiotic relationship - one organism lived inside another |
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Protists |
- Lived in moist environments - Classified in three groups - Algae - Protozoa - fungus-like protists |
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First animals |
Soft bodied invertebrates - bilateral symmetry - facilitates locomotion |
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Diversification of eukaryotes |
1. Genetic changes 2. Environmental changes |
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2 possible origins of multicellular animals |
1. Individuals form a colony 2. single cell divides and stays stuck together |
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Advantages of being multicellular |
- Control internal environment - Grow and become better predator - Division of labour, specialization of cells in organisms - Ability to occupy new ecological niches/environments |
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Disadvantages of being multicellular |
- Complexity of cells may render organisms more prone to extinction as environments change over geological time. |
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Major Environmental Changes |
Land mass glaciation Climate/Temperature Atmosphere Flooding Volcanic Eruptions Meteor impacts |
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Cambrian Explosion |
- Warm and wet climate - O2 levels as seen today - Major increase in diversity of animal species - Lasted 20-25 Million years |
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Characteristics of a predator |
- Very fast - Very powerful - Capable of great patience |
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Trilobites |
- During the Cambrian era, for 250 million years they were the most advanced life form. - 50,000 types known - Have exoskeletons, made of chitin - very good eyesight |
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Paleozoic era |
- starting 550 million years ago - "ancient life" - consists of - Cambrian - Ordovician - Silurian - Devonian - Carboniferous - Permian |
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Ordovician Period |
490-443 million years ago
- Warm and humid - Marine invertebrates - Invasion of land by ancestral plants and arthropods |
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Land plants |
- Evolved from algea - Members of green algea (Coleochaetes) believed to have given rise to the embryophytes (vascular plants, bryophytes) |
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First land animals |
- First fossil identified animals were myriapods (current day millipedes) |
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Adaptions to live on land |
1. Obtain water 2. Prevent water loss 3. Obtaining sufficient energy 4. Coping with variable temperatures especially in polar regions |
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Silurian Period |
443-417 million years ago
- Relatively stable climate - Glaciers mostly gone - many new fish, vertebrates and plants
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Devonian Period |
417-354 million years ago
- Major increase in number of terrestrial species - First seed plants (gymnosperm) emerge - Insect emerge
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Carboniferous Period |
354-290 million years ago
- rich coal formed cooling - cooler, land covered by forests - first flying insects - first reptiles |
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Permian Period |
- Pangaea formed - Seasonal flucuations - End of Permian period experienced largest mass extinction event
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Extinction |
- No longer in existence - Disappears from fossil record - No more of species being born |
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Functional extinction |
- Very few left - Odds of population regrowth very unlikely |
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Reasons of mass extinctions |
1st - Glaciers formed, lowering water levels and cooler water temperatures. Lost of marine life gone. 2nd - Not entirely known, two meteors did hit the earth at this time 3rd - Enormous meteor collides with earth, releasing toxic CO2 and H2S into the atmosphere, wiping out 90%-95% of species. |
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Number of species on the earth |
- Approx 1.2-1.4 million - Could possibly be that 84% of species on earth are undiscovered - Most are very small organisms |
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Influences species distributions |
- Biotic: interactions among living things - Abiotic: interactions between organisms and their non-living environment |
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Factors of distribution |
1. Temperature 2. Wind 3. Water availability 4. Light 5. Salt concentrations 6. pH levels
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3 types of photosynthesis |
1. C3 2. C4 3. CAM |
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Plants/Animals accustomed to salty environments |
Plants: Halophytes - Plants that tolerate igh salt concentrations, may have salt glands to excrete salt Animals: Euryhaline - Animals that can ingest salt water and excrete salt from gills/kidneys |
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Fish are abundant in what type of environment in terms of pH |
6.5-9.0 pH level. Don't like acidic environments, like more basic ones. |
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Definition of Climate |
Temperature, water, wind and light. It predicts the occurrence of specific biomes. Can be modified by: - Proximity of land mass/water bodies - Ocean currents |
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Biomes |
Geographical area with characteristic plants/animals. Largely defined by climactic conditions |
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Tundras |
- Permafrost, cold, high winds, no trees - Covers 20% of earth - Low moisture, low shrubs, lichens and flowers |
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Tropical rain Forests |
- Warm, wet, shallow soils that are nutrient poor. - Thick canopy blocking light - High biodiversity |
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Tropical deciduous forests |
- Seasonal (Hot wet season, Hot dry season) - Not as tree dense as Tropical rainforests
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Temperate Rain Forests |
- Moderate climate, lots of rain - Floor covered in mosses/ferns - Relatively high animal diversity |
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Taiga (Boreal Forest) |
- One of largest biomes - Moderate moisture - Mostly coniferous trees - Very seasonal, seasonal influx of animals (birds) |
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Temperate grass lands |
- Moisture too low to support forests - Continental climate - Soil is very rich in organic nutrients - Most endangered biome in the world
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Tropical Grassland (Savannah) |
- Low to medium biodiversity - Grasses and trees scattered in clumps - Very dry, limited rainfall - Most habitants can wait long periods to get water |
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Desert |
- Plants and animals adapted for water storage - Very hot or Very cold - Low species biodiversity - Reptiles abundant in this biome |
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Aquatic biomes |
- Cover ~75% of earth, majority of living space (~90%) - Lakes, wetlands, coral reefs, Rivers/streams
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Oligotrophic lake |
- Nutrient poor, clear water, oxygen rich, winter kill unlikely, little to no algae - High diversity of fish |
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Eutrophic lake |
- Nutrient rich, high algae content, oxygen poor, winter kill likely - Low diversity of fish |
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Wetlands |
- High biodiversity and high productivity - Plants are hydrophytic - (submerged in water), floating or emergent - Plants adapted to low oxygen
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Rivers and Streams |
- Heavily affected by human activities - Benthic (bottom dwelling) macrophytes and aquatic insects are a diverse group |
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Estuary |
- Where freshwater streams or rivers merge with an ocean - Highly productive, many euryhaline species
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Each ocean has ____________ & _______ species |
1. Cosmopolitan 2. Endemic |
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Coral reefs |
- Greatest biodiversity - Pacific have more species than Carribean reefs - Australia home to single biggest reef
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Mangrove forests |
- Frost sensitive, found where temp is stable (between 25S and 25N) |
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Sea Grass Beds |
- Found in shallow protected bays - Eelgrasses and wigeongrasses dominate temperate sea grass meadows - |
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Species distribution |
- Manner which biological taxon is arranged |
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Community Ecology |
- Species generally don't live in isolation - Species in given area at same time called "community"
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Biological diversity/Biodiversity |
- Number of different kinds of organisms that make up a community - degree of variation of life forms - Genetic - Ecosystem - Species |
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2 main components of diversity |
1. Species richness - Number of different species 2. Species diversity - relative abundance in a community - Combination of evenness |
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Three hypotheses that describe gradient species richness |
1. Time Hypothesis 2. Area Hypothesis 3. Productivity Hypothesis |
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Time Hypothesis |
- Communities gain species and diversify over time |
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Area Hypothesis |
- Larger areas have more species because they can support larger populations in greater range of habitats |
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Productivity Hypothesis |
- Increase in plant biomass will support more diverse species
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Diversity-Stability Hypothesis |
- States that species rich communities are more stable |
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Disturbance |
- A force that alters a biological community and usually removes organisms - Natural disturbances/Human disturbances |
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Ecological Succession |
- Gradual and continous change in species over time following a disturbance - Primary succession is on a newly exposed site with no soil and vegetation - Secondary succession is on a site that has already supported life but has undergone a disturbance |
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Climax communites |
- Consists of colonizers (oppertunistic species, short lived, small, rapid growth) and equilibrial species (larger, longer lived, more competitive) |
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Mechanisms of succession |
1. Facilitation - Colonizing of species change the environment so it becomes more suitable for their next successional 2. Inhibition - Early colonists dictate how the community proceeds often by exclusion 3. Tolerance - Any species starts the succession, but the eventual climax is reached in orderly fasion
1. Facilitation - species replacement facilitated by previous colonists. 2. Inhibition - species replacemnt is inhibited by previous colonist 3. Tolerance - species replacement is unaffected by previous colonist |
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Restoration ecology |
- Habitats that have been through a disturbance and are restoring - Invasive species management - Restoration efforts typically follow natural course |
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Islands |
- New islands formed every day - Helps scientists study how primary succession proceeds - Examples of islands include: - Piece of land surrounded by water - Oasis in desert - Park in a city - Wetland surrounded by farmland |
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How do organisms reach islands? |
- Fly to it (Air) - Hitchhike (Attach to birds) - Float to it/swim (Water) - Human introduction |
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Factors of species richness on island |
- Size -Distance from mainland - Age of island - Number of species already on it |
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Island Equilibrium Model |
- Number of species on an island tends toward and equilibrium number that is determined by balance between rate of immigration and rate of extinction |
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Island equilibrium graph |
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Immigration curve |
- As colonists arrive on island, rate of arrival drops of new species |
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Extinction curve |
- As colonists fill an island, rate that species dissapears increases |
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Adaptive radiation |
- Proccess where single ancestral species evolves into wide array of descendant that differ in habitat, behavior or form |
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Predators |
- Important population controllers - Removal of predator can cause major changes in community |
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Keytone predators |
- Species with a largwe role in shaping community structure - Can actually increase biodiversity in communities |
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Invasive species |
- Have an advantage as they have no predators to control them |
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Parasitism |
- Predator to prey relationship. Parasite relies on host for food. - Symbiotic relationship as one species lives on or on another species. - Does not normally kill host outright |
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Classification of parasites |
1. Host range - monophagous - Feed on 1 or 2 closely related hosts - polyphagous - feed on many hosts 2. Size - microparasites - multiply within host - macroparasites - live in host but release young outside 3. Site - ectoparasites - live outside body - endoparasites - live inside host |
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Parasitic plants |
- holoparasites - lack chlorophyll and dependants on host plant no food
- hemiparasites - photosynthesize but lack root system |
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Graph of species interactions |
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Stability of ecological Communities depends on three things |
1. Species richness 2. Species composition 3. Pattern of interactions |
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Biotic vs Abiotic communities |
Biotic - species richness, relative abundance, interactions (community)
Abiotic - temp, water, light, soil, mineral |
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Leading causes of biodiversity loss in ecosystems |
1. Introduces species (no predator to control) 2. Overharvesting 3. Habitat destruction 4. Climate chnage 5. Pollution (urban, agricultural, industrial)
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Food chains and Food Webs |
Food chain - Linear Primary producer (autotrauph) -> Primary consumer - > Secondary Consumer -> Tertiary consumer
Food Web - Complex, lots of different interactions |
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Negative human activities on ecosystems |
1. Introduced species (No predator) 2. Overharvesting 3. Habitat destruction 4. Climate change 5. Pollution |
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Energy Flow |
- Energy flows through produces to consumers |
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Nutrient flow |
- Nutrients (Matter, elements) are recycled through ecosystem |
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Biogeochemical |
- Nutrients are continuously cycled and rebuilt into new molecules |
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Carbon cycle |
Carbon in atmosphere, autotrophs take up Carbon and convert into organic compounds, respiration and decomposition of plants recycles carbon, back into atmosphere
Natural and human activities increase Carbon in atmosphere (CO2) |
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Climate change effects |
- Regions expected to become warmer - Major climate changes may result in mass migration and range shifts - May occur to rapidly for many species to adapt - May result in massive biodiversity losses - Plants are particularly susceptible to extinction as seed dispersal to more suitable climates can take decades |
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Nitrogen cycle |
1. Nitrogen fixation - Only certain bacteria can convert N2 and release ammonia or ammonium 2. Nitrification - soil bacteria convert ammonia and ammonium to nitrate for plants 3. Assimilation - Plants take up Nitrate 4. Ammonification - conersion of organic nitrogen to NH3 and NH4 by bacteria 5. Denitrification - reduction of nitrate (NO3) to gaseous nitrogen N2 |
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Sulfur cycle |
- Fossil fuel burning produces acid precipitation - Low grade coals have high sulfur content - Low grade coal used in electrical generating plants
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Acid rain |
- High sulfur content - Acidity of rain damages forests, water sources - Acidity releases aluminium in bound in soil which can be toxic |
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First Half Notes
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First Half Notes
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Rare earth hypothesis
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- Complex life on earth required an improbable combination of events and circumstances
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Principal of mediocrity
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- Earth is not in a central, specially favorable position
- Other planets through out the universe have life |
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Living cells unique characteristics
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- Composed of cells
- Shared biomolecules - Biogenesis via reproduction - Arise from common ancestors |
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LUCA
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Last Universal Common Ancestor
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Characteristics of a cell
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- Always surrounded by plasma membrane
- Membrane separates internal from exterior - Small size as they are subject to surface area to volume ratio |
