Ecology and the Environment

• Farmers may use selective breeding to only allow fast-growing fishes to reproduce, resulting in a large population of fish.
• Population refers to the number of organisms in an area.
• Community is an interacting group of various species in a common location.
• Habitat is a place where an organism makes its home.
• Environment is a place where organisms live or occupy.
• Quadrats are rectangular frames of known dimensions that can be used to establish population densities by counting and identifying organisms within frame.
• Estimating population size of an organism involves placing a quadrat randomly within sampling area, counting the number of members of the same species within the quadrat, and repeating this numerous times within sampling area using the same size quadrat.
• Comparing results can be done by repeating the process in another area.
• Calculating the approximate population size of an organism involves an equation: Number of organisms in an area divided by the area of the quadrat.
• Biodiversity refers to the variety and variability of life on Earth.
• Quadrants are square made of wires that is divided into smaller areas in which organisms underneath are identified and counted.
• Measuring distribution and biodiversity of an organism involves placing a quadrat randomly within sampling area, counting the number of members of the same species within the quadrat, and repeating this numerous times within sampling area using the same size quadrat.
• Increasing reliability of results can be done by randomly placing a quadrat, using a quadrat of same size with each repeat, and taking more samples to collect larger data size.
• Abiotic factors are non-living environmental factors that can affect organism in ecosystem.
• Biotic factors are interactions between living organisms.
• Producers are organisms that make their own food.
• Consumers are organisms that cannot produce their own food so they must eat other plants/ animals to get energy.
• Decomposers are organisms that break down dead organic material.
• This is a food web, a food chain within it is highlighted.
• Only 10% of energy is transferred between trophic levels because much of the energy consumed is used to carry out the organisms own bodily functions.
• Carbon Cycle is a process that shows how Carbon is recycled between living organisms and the environment.
• Plants will absorb Nitrates through their roots via active transport, producing Amino acids that form Proteins to increase biomass.
• If decomposition does not occur, incomplete decomposition over a long period of time may lead to fossilization of an organism to form fossil fuels, which when combusted, will return Carbon Dioxide back into the atmosphere.
• Lightning will convert Nitrogen gas into Nitrates.
• The Nitrogen Cycle involves the recycling of Nitrogen in the environment.
• Denitrifying Bacteria in soil will break down Nitrates to return Nitrogen gas into the Air; this occurs in waterlogged soil and can hence be prevented by increasing drainage.
• Water vapour, carbon dioxide, nitrous oxide, methane, and CFCs are greenhouse gases.
• Combustion of Fossil fuels produces Sulphur Dioxide, which will dissolve in clouds composed of Water droplets to form Dilute Sulfuric acid (Acid rain).
• Acid rain damages the waxy layer of leaves, reducing ability of Plants and Trees to absorb Mineral ions needed for growth.
• Acid rain acidifies rivers and lakes, resulting in death of aquatic organisms.
• Acid rain corrodes Metals (steel) and Limestone in buildings.
• Animals in food chain will consume Plants to absorb Nitrogen found in Plant Protein, building Protein in Animal.
• Nitrogen gas in the atmosphere is too unreactive to be used directly, it needs to be converted into soluble ions.
• Carbon Monoxide may cause Emphysema due to insufficient Oxygen via aerobic respiration.
• Incomplete combustion of Fossil fuels produces Carbon Monoxide, which binds irreversibly to Haemoglobin to reduce capacity of red blood cells to transport Oxygen.
• Haber process in soil will convert Nitrogen gas into Ammonia, which Nitrifying Bacteria will convert into Nitrates.
• Dead organisms and faeces from egestion are broken down by Decomposers to remove and return Carbon Dioxide gas to the atmosphere.
• These processes ensure a constant supply of Nitrates for use by Plants.
• Nitrifying Bacteria will convert Ammonium ions deposited in soil into Nitrates for Plants to absorb.
• Nitrogen-fixing Bacteria in Root nodules of Legumes will convert Nitrogen gas into Nitrates for use by Plants.