BIOLOGY TOPIC 4 ECOLOGY
Ecology 4.1-4.4
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| Species | Organisms that breed together to make fertile, successful offspring |
| Abiotic factors | Non living parts of the ecosystem (water, light, humidity) |
| Biotic factors | Living parts of the ecosystem (animals, fungi) |
| Population | Number of same species in the same place at the same time |
| Community | Many populations interacting together in an area |
| Habitat | The environment |
| Ecosystem | Abiotic and biotic factors interacting with each other |
| Nutrient | Material needed by organisms for growth and nourishment |
| Autotroph | Make their own food from inorganic molecules to organic molecules Use sun as their main source of energy from the abiotic environment light energy converted into chemical energy Synthesises carbon compounds Via Photosynthesis Inorganic carbon source |
| Heterotrophs | Ingest other organisms to get nutrients and energy Can't synthesise their own carbon compounds obtains them by ingesting other organisms Organic carbon source |
| Consumers | Ingest other organisms |
| Detritivores | Non living organic sources like detritus and humus (earthworms, snails) |
| Saprotrophs | Non living organic matter by secreting digestive enzymes (ED) = break down dead organic material |
| Why are decomposers so important? | They clear up waste from the environment which prevents the spread of disease and make important nutrients available to producers again |
| Compare the fate of energy and nutrients within an ecosystem | Inorganic nutrients are constantly recycled but energy is lost as heat energy into the atmosphere, cant be recycled |
| What is a mesocosm? | Confined environments to observe under controlled conditions |
| What are three components needed for an ecosystem? | Energy - Sun Nutrients - Saprotrophs and producers Recycling of wastes - removes waste products (bacteria) |
| What is quadrat sampling? | Frame for finding out population densities Placed in an area randomly or by pattern No of orgs counted and repeated |
| How to do chi squares? | 1.) Table of frequencies with expected and observed (expected = (row total *column total)/Grand total)) 2.) Chi formula = (O-E squared)/E and add up all the answers for x squared 3.) Degree of freedom = 1 (df = (m-1)(n-1)) m = no rows n = no columns 4.) Identify P value = signif if less than 5% prob (p < 0.05) |
| What happens when heterotrophs ingest organic compounds? | They break it down by cell respiration making ATP for processes |
| What do the arrows in a food chain show? | Transfer of energy and matter (direction of E flow) |
| Why isn't all the chemical energy used by organisms? | Excreted waste products Remaining unconsumed parts of food |
| How efficient is energy went passed along a food chain? | ~10% efficient, other 90% is lost between trophic levels |
| Why do higher trophic levels have lower biomass? | Less energy in the higher levels => store less energy as carbon compounds => fewer organisms => less biomass |
| Why does biomass decrease along a food chain? | Loss of carbon dioxide, water, waste products and metabolic heat to environment |
| Biomass | Total mass of groups of organisms |
| Why are trophic levels limited? | Because energy and biomass is lost between each level |
| Why do higher levels eat more? | They get less energy from feeding so they eat more for sufficient nutrition and energy |
| What is a feature of shorter wavelength visible radiation? | It includes violet light |
| What characteristic of water vapour makes it a greenhouse gas? | It absorbs then re-emits some of the long wave radiation emitted by the earths surface |
| How is carbon exchanged in the atmosphere => ocean | Oceanic carbonates = bicarbonates dissolve in water + calcium carbonates in corals and shells |
| What should the concentration gradient be in the atmosphere and autotroph? and why? | CO2 should be higher conc in atmosphere than the autotroph when it is carrying out photosynthesis which allows the CO2 to passively diffuse in |
| What is cell respiration? | Breaks down organic molecules and produces carbon dioxide as a byproduct CO2 builds up in cells and gets removed by passive diffusion uptake and co2 production balance = compensation |
| How is carbon dioxide converted in the ocean? | Combines w water => carbonic acid (H2CO3) Dissociates=> hydrogen carbonate ions and hydrogen ions (HCO3- + H+) H+ = PH more acidic Autos use CO2 AND HCO3 for photo |
| How is limestone formed in the ocean? | Hydrogen carbonate ions +rocks (metal ions) => Calcium carbonate => limestone Living animals + hydrogen carbonate => calcium carbonate |
| What is calcium carbonate used as for corals? | Forms hardened exoskeleton and main comonent of mollusca shells |
| What happens to the hard components after the organism dies? | It fossilizes into limestone |
| How is methane produced? | From organic matter in anaerbic conditions by methanogenic archaens |
| Ruminants | Herbivourus , aquire nutrients by fermenting in stomach w/ microbial actions |
| Archaea | Single celled prokaryotic organisms without defined nucleus |
| Where are methanogens found? | Wetlands Mud Ruminant animals (cows) |
| How does methane form (formula) | Acetic acid => methane + CO2 (CH3COO- + H+ => CH4 +CO2) or (CO2 + 4H2 => CH4 +2H20) |
| Flow of methane in ruminants | HYSIS (poly) , ACIDOS (moly) AND ACETOS (alcohol) = METHANE (acetate) |
| What does methane turn into and how? | Carbon dioxide and water by oxidising |
| How does peat form? | When organic matter isn't fully decomposed because of acidic / anaerobic conditions in waterlogged soils |
| What is the method of partial decomposition? | Waterlogged soil has anaerobic conditions (lacks oxygenated spaces) = organic acids (acetate) bec of acidic conditions Bacteria and fungi dont function well = prevents decomposition |
| Peat | Accumulation of partially decomposed org matter |
| How does coal form? | When peat is compressed under sediments, heat and pressure removes impurities and moisture = high carbon concentration => coal |
| How does oil / natural gas form? | Forms from marine decay on ocean floor sediments layer on top creating anoxic conditions => prevents decomposition burial and compaction => heated and hydrocarbons form oil and gas accumulates in porous rocks (sandstone) |
| What is combustion? | When oil and coal is heated with oxygen present |
| What type of reaction is combustion? | Exergonic because it produces energy |
| What does combustion produce as a byproduct? | Carbon dioxide and water |
| What are the two combustion sources? | Fossil fuels and biomass |
| How is biomass used as a fossil fuel? | Organisms make hydrocarbons as their total biomass (use or waste product) Extracted and purified = bioethanol and biodiesel Renewable |
| What does the carbon flux depend on? | Photosynthesis: removes Respiration: releases Decomposition: releases when recycled Gaseoues dissolution: removes (ocean and atmos) Lithification: removes (carbon in sediments) Combustion releases (burned) |
| What are the main causes for flux change? | Climate Natural events Human activity |
| How does climate change affect carbon fluxes? | Photo higher in summer - less carbon Warmer oceanic temps = less stored dissolved carbon Melting ice caps = more carbon (decomposition of frozen detritus) |
| How do natural events affect carbon fluxes? | Forest fires rlease high CO2 levels = reduces carbon uptake Volcanic eruptions = releases carbon compounds into amosphere |
| How do human activity affect carbon fluxes? | Deforestation - reduces carbon removal More ruminant animals = more methane Burning FF - releases CO2 |
| What is the pattern of carbon flux? | CO2 levels go up and down yearly= lower in summer Global trends depend on nortern hemisphere bec majority of landmass CO2 levels increase yearly bec of inndustrial revolution = more FF burning |
| Steps for analysing carbon data: | 1. Access the [CDIAC website](http://cdiac.ornl.gov/) 2. Click on ‘Atmospheric Trace Gases and Aerosols’ (under ‘Data' tab at top of page) 3. Select ‘Carbon dioxide’ from the list of greenhouse gases 4. Choose a monitoring station / network (e.g. Scripps Institution of Oceanography Network) 5. Download data from a particular site (e.g. South Pole, Antarctica) 6. Paste data of interest into an Excel spreadsheet to produce a graphical display (e.g. Jan 2000 – Dec 2007) |
| What do greenhouse gases do that define it? | Absorb and emit long wave (infrared) radiation to trap and hold heat within the atmosphere |
| Which two gases have the largest warming effect on the atmosphere? | Water vapour and carbon dioxide |
| Water vapour | Evapouration of water from water bodies and transpiration removed by rain |
| Carbon dioxide | From cell respiration + from burning FF and removed by photosynthesis and oceans |
| Methane | From waterlogged habitats and ruminants |
| Nitrogen oxides | From bacteria and vehicle exhausts |
| What causes the most impact in greenhouse gases? | Its ability to absorb long wave radiation bec they have a higher warming impact |
| Why doesn't methane have a greater warming effect? | It absorbs more long wave radiation than CO2 but less abundant |
| Why is water vapour not as dangerous as CO2 even though it is more abundant? | It enters rapidly but lasts short term whereas CO2 lasts for years |
| What is the greenhouse effect? | When the atmosphere traps heat in to keep earth at moderate temps for life processes |
| How does greenhouse effect work? (method) | Incoming radiation is shorter (UV and visible) Earths surface absorbs and re emits as a longer WY (infrared/heat) GG absorb + reradiate the longer WY = retains heat within |
| How does an increase in greenhouse gases affect the climate? | More extreme weather conditions (heat waves, cyclones) Drought affected areas / heavy rainfall Changes to ocean currents |
| How is CO2 concentrations been measured over the year? | Vostok ice core which was drilled 420,000 years ago analysing gas bubbles trapped in ice = deduce CO2 levels |
| What does the vostok ice core data show? | Strong + link w/ CO2 concs and temp current CO2 levels are higher than any other time recorded before |
| What are the different climate change debates? | Current trends are the earths natural climactic cycle because its changed before But these days the changes are too abrupt. This abrupt in the past = v destructive |
| What are the different climate change debates? | Climate change is because of solar activity over last 35 years = shown cooling trend but temps have been increasing no evidence to support |
| What are the different climate change debates? | Some changes cant be linked to GG emissions bec sea levels were increasing before the IR depends on the time period where data is collected rate of increase is higher than before |