last test
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| 167736919 | What makes up biodiversity? | the variety of life on earth and the natural distribution and patterns of organisms | |
| 167736920 | How many species have been identified? | 1.5 million named species identified (70% invertebrates) 3-50 million species alive: only identified a small proportion | |
| 167736921 | Why is biodiversity important? | Nature's products support industries and the loss of biodiversity threatens our food supplies and sources of medicine and energy. | |
| 167736922 | What is Background Extinction? | Gradual loss of species. 95% of all extinctions. | |
| 167736923 | What are some factors that contribute to background extinction? | climate change, disease, loss of habitat, or competitive disadvantage in relation to other species. | |
| 167736924 | What is the background extinction rate? | 1 mammal species every 400 years and 1 bird species every 200 years. | |
| 167736925 | What is Anthropogenic Extinction? | extinction caused by humans | |
| 167736926 | What is the Anthropogenic extinction rate? | 20-75 plant/animal species each day. Now 10,000 times the background rate | |
| 167736927 | What are the two biggest threats to endangered mammals in order? | habitat losses then exploitation | |
| 167736928 | Define Threatened species | population is low but extinction less imminent | |
| 167736929 | Define Endangered species | numbers so low that extinction is imminent | |
| 167736930 | What are the 5 common characteristics of threatened, endangered, or extinct species posses | 1. Small range (small geographic area) 2. Specialized habitat/diet 3. Low reproductive rates & low natural morality 4. Slow-moving animals 5. Wild animals and plants which have value as food, pets, ceremonial objects, or marketable products to humans. | |
| 167736931 | Why are wetlands important? | - help control floods by storing water until it gradually drains - provide habitats for many species - as water flows through the plants wastes are absorbed by plants and waste materials settle out allowing the water to be naturally filtered | |
| 167736932 | What are the rates of deforestation? | since 1978, we've lost 20% of tropical forest (about 13 million hectares of the worlds forests are lost each year) | |
| 167736933 | List the 3 countries in order that have the highest rates of deforestation | Brazil highest (over 3,000 hectares), then Indonesia, then Sudan. | |
| 167736934 | Why are forests important? | Tropical forests are system regulators as well as habitats. Rainforests moderate air temp, maintain humidity through evapotranspiration, and regulate stream flows. Amazon is 30% of world's rainforests and acts as the "Earth's lung", absorbing carbon dioxide and generating oxygen | |
| 167736935 | What is the definition of soil? | The unconsolidated mineral or material on the immediate surface of the earth that serves as a natural medium for the growth of land plants | |
| 167736936 | Describe the soil forming process | forms very slowly; begins with breakdown of rock into loose material. Soil formation refers to changes within this loose material (aka parent material) over time into layers/horizons. | |
| 167736937 | What is the equation for soil formation? | Soil formation = f (climate, organic matter, relief, parent material, time) | |
| 167736938 | Define soil erosion. (includes 2 steps) | removes soil from an area in two steps: 1. Detachment of particles from the surface 2. Transport of particles by erosive agents (normally wind or water). | |
| 167736939 | What are the 6 soil horizons and their identifications? | O - surface litter A - topsoil E - zone of leaching B - subsoil C - weathered parent material R - bedrock | |
| 167736940 | What are the two major soil types in the US? | Mollisols & Ultisols | |
| 167736941 | What is the definition of soil/land degredation? | the aggregate reduction of the productive potential of the soil. Primary cause is erosion by wind and water, also caused by chemical degradation and physical degradation (compaction). | |
| 167736942 | Define the T-Value for soil degredation | (Tolerable Erosion Value): the allowable rate of soil loss in a particular region. | |
| 167736943 | What is the definition of point source pollution? | effluent being released from a single outlet, meaning it easier to monitor and control (sewage plants, discharge from specific locations) | |
| 167736944 | What is the definition of non-point pollution? | pollution that cannot be linked directly to one specific source (diffuse discharge, agricultural runoff, feedlots) | |
| 167736945 | Why is the #1 pollutant the introduction of sediment into waterways? | Too much sediment into a stream can lead to detrimental effects on native aquatic life, can act as a storage unit for other pollutants. 10% of sediment underlying surface water is significantly contaminated. | |
| 167736946 | What are Debt-for-Nature swaps? | financial transactions in which a portion of a developing nation's foreign debt is forgiven in exchange for local investments in environmental conservation measures. |
