Presentation on theme: "Environmental Science Chapter 15 Review"— Presentation transcript:
1 Environmental Science Chapter 15 Review Arable land – able to grow cropsSoil formation –involves bedrock decompositionTopsoil – upper layer of soil- rock particles, water, air, organic matterYield – amount of a crop per hectare (acre)Soil erosion (fields) – caused by farm machineryDesertified farmland-domestic animals overgraze the land-too many crops are grown/looses fertility-as a result of erosion
2 Environmental Science Chapter 15 Review Irrigation water usually comes from rivers & groundwater.Salinization – accumulation of salts in the soil caused by irrigation & low rainfallUsing rainwater instead of groundwater on crops reduces soil salinization.Using strips of vegetation in between plowed land reduces soil loss caused by wind & water.
3 Environmental Science Chapter 15 Review No-till farming – seeds planted among roots of previous crop.Livestock – cattle, goats, pigs, sheep, chickensRuminants – cud-chewing mammalsWheat requires less energy than cattle or cows.Modern Agricultural methods use plowing machines, drip irrigation systems, and chemical fertilizers.
4 Environmental Science Chapter 15 Review DDT harmful to environment-does not break down easily in environment-causes some birds to lay thin shelled eggs-concentrates in animal bodies(persistent pesticides)Pest- organism that occurs where it is not wanted- can become resistant to pesticides
5 Environmental Science Chapter 15 Review Integrated pest management – chemical, biological & farming methodsFood production has not been increasing as fast as the human population – many go hungryFamine – widespread food shortageMalnutrition – health problem due to not eating necessary nutrients
6 Environmental Science Chapter 15 Review Humans need 8 essential amino acids from the proteins they eat.Carbohydrates supply energy for the body.Lipids (fats & oils) help form membranes/hormones.
7 Environmental Science Chapter 15 Review Aquaculture- raising of aquatic organisms for human use– reduce seafood overharvestingNo fishing zones – reduce effects of overharvestingGenetic Engineering – desirable traits transferred
8 Environmental Science Chapter 15 Review Living organisms maintain soil fertility-fungi, bacteria, microorganisms decompose dead plants/animals/excrement-certain bacteria convert atmospheric nitrogen into forms plants can use.-earthworms, insects, small animals break up soil, letting in water/air.
9 Environmental Science Chapter 15 Review Reducing water erosion of farmland-mixing in stems, roots from previous crops-loosens topsoil so water soaks in/not run off-worms attracted to this organic material-aerate topsoil so water soaks in/not run off-contour plowing stops water running downhill
10 Environmental Science Chapter 15 Review Biological insecticides (bacteria, reproductive-interfering agents) - target pests but do not harm others.Chemical insecticides can persist or build up and then harm other species which feed on the insects.
11 Environmental Science Chapter 15 Review Erosion in farmingonly recently a serious problem (modern machinery & practices)previous farmers did not leave bare soil exposed in huge fieldssmall fields & gardens = less runoffpracticed crop rotationfields allowed to lie fallow every few seasons
12 Environmental Science Chapter 15 Review Explain how pests develop a resistance to pesticides.Word bank = aquaculture, famine, genetic engineering, livestock, malnutrition, meat, overharvesting, pest, ruminants, salinization, topsoil, yield.