Untitled

Ecology and the Environment

4.1-4.5 The Organism in the Environment

• Population: all the organisms of one species living in the same habitat
• Community: all the populations of organisms that live in an area or ecosystem
• Habitat: a small part of an ecosystem where a species lives
• Ecosystem: a system in which organisms interact with each other and their environment
• Biodiversity: a measure of the variety of organisms in an area
• Population exp: random number generator for grid coordinates to place quadrat, count how many in each quadrat, find number per square metre, multiply by area
• Distribution exp: tape measure, place a quadrat at equal lengths along the transect, count how many in each quadrat
• Abiotic: light intensity - light required for photosynthesis, temperature - affects the rate of photosynthesis, water levels - needed to survive
• Biotic: food availability - organisms can breed successfully, pathogens - can kill organisms, competition - some animals can't get food or water

4.6-4.9 Feeding Relationships

• Producer: an organism that produces its own food
• Primary: an animal that eats plants (a herbivore)
• Secondary: an animal that eats primary consumers
• Tertiary: an animal that eats secondary consumers
• Decomposer: an organism that causes decay of dead material (fungi and bacteria)
• Food chain: shows the feeding relationships between organisms
• Food web: shows many interdependent food chains
• Pyramid of number: shows the population at each trophic level, often a pyramid shape, for a large plant the bar size is small as 1 tree feeds many insects
• Pyramid of biomass: shows the biomass at each trophic level, often a pyramid shape, not all the food consumed is converted into biomass
• Pyramid of energy: shows the energy content at each trophic level, always a pyramid shape
• Energy loss: 10% transferred as organisms don't normally eat every part, bits they eat might not be absorbed, biomass gets released as waste products

4.10-4.11 Cycles within Ecosystems

• Combustion: burning of fossil fuels which releases carbon back into the atmosphere
• Decomposition (Carbon cycle): dead plants and animals are broken down by decomposers and carbon returns to the atmosphere
• Respiration: plants and animals respire which releases carbon dioxide into the atmosphere
• Photosynthesis: plants remove carbon dioxide from the atmosphere through photosynthesis
• Fossil fuels: fuels formed organic material, such as peat, coal, oil, and natural gas
• Nitrogen fixing: nitrogen fixing bacteria convert nitrogen in the atmosphere into nitrates in the soil
• Nitrification: nitrifying bacteria convert ammonia into nitrates in the soil
• Decomposition (Nitrogen cycle): decomposers convert decaying matter into ammonia
• Denitrification: denitrifying bacteria convert nitrates in the soil into nitrogen in the atmosphere

4.12-4.8 Human Influences on the Environment

• Sulphur dioxide: releases when fossil fuels are burnt, dissolves in water, falls as acid rain, low pH in lakes so fish die, corrodes limestone in buildings
• Carbon monoxide: released when fossil fuels are burnt through incomplete combustion, binds with haemoglobin, no O2 can bind, less O2 transported, people die
• Methane (greenhouse gas): comes from cattle farming and causes global warming
• Water vapour (greenhouse gas): comes from combustion and causes global warming
• CFC (greenhouse gas): comes from refrigerators and affects the ozone layer
• Carbon dioxide (greenhouse gas): comes from burning fossil fuels and causes global warming
• Nitrous oxide (greenhouse gas): comes from burning fossil fuels and causes acid rain
• Greenhouse effect: greenhouse gases absorb sun's heat, trap it above the Earth's surface, which leads to higher temperatures and global warming
• Global warming effects: glaciers melt, water levels rise, loss of habitats, changes om weather patterns
• Eutrophication: nutrients allow rapid growth of algae, algal bloom stops light reaching aquatic plants, oxygen depletion means other aquatic organisms die
• Deforestation: the clearing of an area of trees on a mass scale
• Leaching: without trees nutrients and minerals from the soil run into rivers and lakes
• Soil erosion: without tree roots the soil will be washed away by the rain
• Disturbance: transpiration releases water vapour affecting the water and carbon cycle
• Imbalance of atmospheric gases: removal of trees causes more CO2 levels and lower O2 levels