Env. Science Midterm #2
What are 2 underlying causes of deforestation?
1. Pressures from population growth 2. Poverty
What are the 3 grain crops that 2/3 of people survive primarily by eating?
1. Rice 2. Wheat 3. Corn
How much of wood is used by the US?
60% of the wood used by the US is wasted unneccesarily
How many Americans over age 20 are overweight/obsese?
69%
Replacement:
Replacing a degraded ecosystem with another type of ecosystem
Fisheries/aquaculture:
Supply fish/shell fish, make up about 7% of the world's food supply
When did the 1st Green Rev take place?
1. 1st green rev took place for the first time between 1950 and 1970 A 2nd green rev has been taking place since 1967
What are 3 direct causes of deforestation?
1. Cattle grazing 2. Farming/plantations 3. Global trade
What are 2 ways that farmers can produce more food?
1. Farming more land 2. Getting higher crop yields from existing cropland
What are the 2 types of natural forests?
1. Old growth forests/primary forest 2. Second growth forest
What are the 2 types of traditional agriculture?
1. Traditional subsistence agriculture 2. Traditional intensive agriculture
What are the 4 approaches that speed up ecological succession?
1.) Restoration 2.) Rehabilitation 3.) Replacement 4.) Creating Artificial Ecosystems
How much of the world's grain production do people directly consume?
46%
What is a fact about the grassland ecosystem?
After forests, grasslands are the most widely used ecosystems, and they're also the ecosystems altered most by human activity
Gene splicing:
Alters an organism's genetic material through adding, deleting, or changing segments of its DNA. Goal is to produce desirable traits, eliminate undesirable traits by enabling scientists to transfer genes between different species that would not normally interbreed in nature. Resulting organisms are called GMO's
What must a product be to be classified as organically grown?
Animals must be raised on 100% organic feed without the use of antibiotics or growth hormones
More-developed countries:
Diets are heavy on cheap food loaded with fats, sugar, salt
What is the time scale for ecological restoration?
It takes a long time
Clear-cut:
Loggers remove all the trees from an area. Most efficient, least costly way to cut trees, but the most harmful to an ecosystem
Overnutrition:
Occurs when food energy intake exceeds energy use and causes excess body fat
Green revolution:
Since 1950 about 88% of the increase of global food production has come from using high input industrialized agriculture to increase crop yields
What 2 types of agriculture raise crops?
1. Industrialized agriculture/High-input agriculture 2. Plantation agriculture
What are 5 benefits of surface fires?
1.) Burn away flammable ground material such as dry brush, and help prevent more destructive fires 2.) Free valuable mineral nutrients tied up in slowly decomposing litter/undergrowth 3.) Release seeds from the cones of tree species such as lodgepole pines 4.) Stimulate the germination of certain tree seeds such as those of the giant sequoia and jack pine 5.) Help to control destructive insects/tree diseases
What are the 3 systems that supply most of our food?
1.) Croplands 2.) Rangelands/pastures/feedlots 3.) Fisheries and aquaculture
What are the 3 steps of a Green Revolution?
1.) Develop and plant monocultures of selectively bred or genetically engineered high yield varieties of crops like wheat/corn/rice 2.) Produce high yields by using large inputs of water, synthetic inorganic fertilizers, and pesticides 3.) Increase the # of crops grown/year on a plot of land through multiple cropping
What is the 4 step strategy for carrying out most forms of ecological restoration/rehabilitation:
1.) Identify causes of the degradation (ex: pollution, farming, mining) 2.) Stop the abuse by sharply reducing/eliminating these factors 3.) If necessary: Reintroduce key species to help restore natural ecological processes 4.) Protect area from further degradation, allow secondary ecological succession to occur
What are the 5 steps of the Ecosystems Approach?
1.) Map the world's terrestrial ecosystems and create an inventory of the species contained in each, and their ecosystem services. 2.) Identify terrestrial ecosystems that are resilient and can recover if not overwhelmed by harmful human activities, as well as fragile ecosystems in need of protection 3.) Locate and protect the most endangered terrestrial ecosystems and species, with emphasis on protecting plant biodiversity and ecosystem services 4.) Seek to restore as many degraded ecosystems as possible 5.) Make development biodiversity-friendly by providing significant financial incentives and technical help to private landowners who agree to help protect endangered ecosystems
What are 5 ecosystem services provided by grasslands?
1.) Soil formation 2.) Erosion control 3.) Chemical cycling 4.) Storage of atmospheric carbon dioxide in biomass 5.) Maintenance of biodiversity
What are 5 detriments of logging roads?
1.) They cause topsoil erosion 2.) They cause sediment to runoff into waterways 3.) They cause habitat fragmentation 4.) They cause a loss of biodiversity 5.) They leave forests exposed to invasion by nonnative pests, diseases, and wildlife species
What are 4 major functions of forests?
1.) To remove CO2 from the air through photosynthesis and store it in organic compounds (biomass) 2.) To help stabilize average atmospheric temps and the earth's climate 3.) To provide habitats for about 2/3 of the earth's terrestrial species 4.) More than 1/2 of the wood removed from the earth's forests is used as biofuel for cooking and heating. Remainder is industrial wood for paper/lumber
Chronic malnutrition:
A condition in which people do not get enough protein and other key nutrients. * 1/7 people are chronically undernourished and malnourished as of 2010 *Each year about 6 mill children younger than 5 die from this
What do most people in less developed countries suffer from?
A deficiency of vitamin A, iodine, and iron
Plantation agriculture:
A form of industrialized agriculture used primarily in tropical less-developed countries. Involves growing CASH CROPS like coffee, bananas, veggies, soybeans, etc. on large monoculture plantations, mostly for export to more-developed countries
What is a tree plantation/tree farm/commercial forest?
A managed forest containing only 1 or 2 species of trees that are all of the same age. Usually harvested by clear-cutting as soon as they become commercially valuable. Land is then replanted and clear cut again in regular cycle. Much less biologically diverse/sustainable than old growth/second growth forests because they have only 1 or 2 species
Irrigation:
A mix of methods by which water is supplied to crpps by artificial means
What is a 2nd growth forest?
A stand of trees resulting from secondary ecological succession. Develops after the trees in an area have been removed by human activities, such as clear-cutting for timber or conversion to cropland, by natural forces such as fire/hurricane/volcanic eruption
Habitat corridor:
A strip of protected land connecting 2 reserves that allows animals to migrate from 1 area to another as needed. The UN has used this design concept to create a global network of 621 biosphere reserves in 117 countries
What percentage of earth's land surface do planted and natural forests occupy?
About 31% of earth's land surface, excluding Greenland, Antarctica,
How many national parks are there?
According to the IUCN there are more than 6,600 major national parks. *Parks in less developed countries have the greatest biodiversity of all the world's parks, but only about 1% of these parklands are protected
Crown fire:
An extremely hot fire that leaps from tree top to tree top, burning whole trees. Usually occurs in forests that haven't experienced surface fires for several decades, which allows dead wood/leaves/flammable ground litter to accumulate. Can destroy most vegetation, kill wildlife, increase topsoil erosion, and burn/damage human structures
What is an old growth/primary forest?
An uncut or regenerated forest that hasn't been seriously disturbed by human activities/natural disasters for 200 or more years. They're reservoirs of biodiversity because they provide ecological niches for a multitude of species. Make up 36% of the world's forests
Biodiversity hotspots:
Areas especially rich in plant species found nowhere else, and are in great danger of extinction. Areas have suffered serious ecological disruption because of rapid population growth and the resulting pressure on natural resources/ecosystem services. Norman Myers uses diversity of plant species to identify biodiversity hotspots. Identified hotspots cover a little more than 2% of the earth's and surface
Liferaft Ecosystem:
Areas where poverty levels are high, and where a large part of the economy depends on various ecosystem services which are being degraded severely enough to threaten the well being of people and other forms of life
How does rangeland grass grow?
Blades of rangeland grass grow from the base, not at the tip like many broadleaf plants. Only the upper half of the blade is eaten, lower half remains, so rangeland grass is a renewable resource
Buffer zone concept:
Called for by conservation biologists in the establishment of nature reserves. It means strictly protecting an inner core of a reserve usually by establishing 2 buffer zones in which local people can extract resources sustainably without harming the inner core. This approach enlists local people as partners in protecting a reserve from unsustainable uses such as illegal logging and poaching
Rotational grazing:
Cattle are confined by portable fencing to 1 area for a short time (1-2 days) and then moved to a new location
Riparian Zones:
Cattle tend to aggregate around natural water sources, like these streams and rivers lined by thin strips of lush vegetation known as riparian zones
How much of the world's grassland is grazed on?
Cattle, sheep, and goats graze on about 42% of the world's grassland. UN Millenium Ecosystem Assessment (2005) estimated that this could increase to 70% by 2050
Strip-cutting:
Clear-cutting a strip of trees along the contour of the land within a corridor narrow enough to allow natural forest regeneration within a few years
Tree thinning:
Clearing away small fire-prone trees and underbrush under careful environmental controls. Shouldn't remove economically valuable medium-size and large trees for 2 reasons: 1.) They're usually the most fire resistant trees 2.) Their removal encourages dense growth of more flammable young trees and underbrush, and leaves behind highly flammable slash (the debris left behind by a logging operation)
Wilderness Act of 1964:
Conservationists have been trying to save wild areas from development since 1900. Congress passed this act, which allowed the gov to protect undeveloped tracts of public land from development as part of the National Wilderness Preservation System
Organic agriculture:
Crops are grown with the use of ecologically sound and sustainable methods and without the use of synthetic pesticides, synthetic fertilizers, and genetically engineered plants or animals
Iodine:
Essential for proper functioning of the thyroid, which produces hormones that control the body's metabolism. Lack of iodine can cause stunted growth, retardation, and goiter (which can lead to deafness)
Creating Artificial Ecosystems:
Ex: the creation of artificial wetlands in order to reduce flooding/treat sewage
Polyculture:
Farmers focus on cultivating a single crop, but grow many crops on the same plot simultaneously
Traditional Intensive Agriculture:
Farmers increase their inputs of human and draft animal labor, animal manure for fertilizer, and water to obtain higher crop yields.
Conservation concessions:
Gov's or private conservation organizations pay nations for agreeing to preserve their natural resources
How does grazing lead to healthy grasslands?
Grazing leads to healthy grasslands because removal of mature vegetation stimulates regrowth/encourages plant diversity
Less developed countries:
Hungry people can only typically afford a low-protein, high-carb, veggie diet consisting mainly of grains like wheat, rice, and corn.
William Baker & Mark Williams:
In 2012 research indicated that natural low level fires were not as widespread as other studies had indicated, and that they rarely prevented more severe fires in the Western US
Selective-cutting:
Intermediate aged or mature trees in a forest are cut singly or in small groups
Slash and burn agriculture:
Involves burning and clearing small plots in tropical forests, growing a variety of crop for a few years until the soil is depleted of nutrients, and then shifting to other plots to begin the process again THIS IS A TYPE OF POLYCULTURE
How long does developing a new crop variety through gene splicing take?
It takes 1/2 as long, and costs less, and allows for the insertion of genes from almost any other organism into crop/animal cells
Wilderness:
Land officially designated as an area where natural communities haven't been seriously disturbed by humans, and where harmful human activities are limited by law
Food insecurity:
Living with chronic hunger and poor nutrition, which threatens their ability to lead healthy/productive lives The root cause is poverty Other obstacles: war, climate change, bad weather, corruption/political upheaval For good health, individuals need large amounts of macronutrients (carbs/proteins/fats) and smaller amounts of micronutrients (vitamins/minerals)
Fact about low input polyculture vs high input monoculture:
Low input polyculture produces higher yields than does high input monoculture
Debt for nature swaps:
Makes it financially attractive for countries to protect their tropical forests. Participating countries act as custodians of protected forest reserves in return for debt relief/foreign aid
Pastures:
Managed grasslands/fenced meadows often planted with domesticated grasses or other forage crops like alfalfa and clover.
100% Organic USDA Certified Organic Labels:
Means that a product is produced only by organic methods and contains all organic ingredients
Kenaf:
Most of the paper produced in the US is made from the fibers of this rapidly growing annual plant. "It's the best option for tree-free papermaking in the US"
Croplands:
Mostly grains, provide 77% of the world's food using 11% of its land
Made with organic ingredients labels:
Must contain at least 70% organic ingredients
Organic labels:
Must contain at least 95% organic ingredients
Famine:
Occurs when there is a severe shortage of food in an area, which can result in mass starvation, many deaths, economic chaos, and social disruption
Overgrazing:
Occurs when too many animals graze for too long, damaging the grasses and their roots, and exceeding the carrying capacity of a rangeland area. Reduces grass cover, exposes topsoil to erosion by water/wind, compacts the soil, leaving it less capable to hold water. Encourages invasion by species such as mesquite, sagebrush, cacti, and cheat grass, which cattle won't eat Has caused a loss in productivity by 20% in the world's rangeland
How much of earth's land was protected as of 2012?
Only 13% was protected either strictly or partially. Figure is misleading because no more than 6% of the earth's land is strictly protected from potentially harmful human activities: WE"VE RESERVED 94% OF THE EARTH'S LAND FOR HUMAN USE
How much of US land is protected as wilderness?
Only 5%
Hunger/chronic undernutrition:
People who can't grow/buy enough food to meet their basic energy needs
What does polyculture do to fertilizer use?
Polyculture lessens the need for fertilizer and water, because root systems at different depth in the soil capture nutrients and moisture effectively
What percentage of land is industrialized/high-input agriculture practiced on?
Practiced on 25% of all cropland, produces about 80% of the world's food
Rangelands/pastures/feedlots:
Produce meat and fish products, supply about 16% of the world's food using 29% of the land area
Restoration:
Returning a degraded habitat/ecosystem into a condition as similar as possible to its natural state. Problem is we do not always know what the original state was, and restoring it may no longer be feasible because conditions have changed
Traditional crossbreeding:
Slow process, 15 years or more to produce a commercially valuable new crop variety, can only combine traits from species that are genetically similar. Resulting varieties remain useful for only 5-10 years before pests, diseases reduce their yields
Reconciliation ecology:
Suggested by ecologist Mike Resenxweig, it's a form of conservation biology. Focus is on learning how to share with other species some of the spaces that we dominate. Aims to invent, establish, and maintain new habitats to conserve species diversity in areas where people work, live, play
Traditional Subsistence Agriculture:
Supplements energy from the sun with the labor of humans and draft animals to produce enough crops for a farm family's survival, with little left over to sell or store as a reserve for hard times
What does the ecosystems approach recognize?
That most of the world's ecosystems are already dominated/influenced by human activities and that such pressures are increasing as human population, urbanization, resource use, and the human ecological footprint all expand. Contends that their efforts won't significantly slow the steady erosion of the earth's biodiversity and ecosystem services
Food security:
The condition under which all or most of the people in a population have daily access to enough nutritious food to live active/healthy lives * 1/6 people in less developed countries aren't getting enough to eat. 1/6 people struggle to live on $1.25 a day
Ecological Restoration:
The process of repairing damage caused by humans to the biodiversity and ecosystem services provided by ecosystems. Ex: Replanting forests, reintroducing native species, removing invasive species, etc.
Deforestation:
The temporary/permanent removal of large expanses of forest for agriculture, settlements, or other uses. During the past 8,000 years, human activities have reduced the earth's virgin/frontier forest cover by about 47% with most of the loss occurring in the last 60 years *Net loss of 20,000 square miles/52,000 sq km of forest/yr * If current rates continue, about 40% of the world's remaining forests will have been logged/converted to other uses within 2 decades if not sooner
What is a fact about food supply in relation to plant species?
There are 50,000 plant species, only 14 supply about 90% of the world's food calories.
What is the 1st step in harvesting trees?
To build roads for access and timber removal
Prescribed burns:
To set small, contained surface fires to remove flammable small trees and underbrush in the highest-risk forest areas
What is the goal of industrialized/high-input agriculture?
To steadily increase each crop's yield: aka the food amount produced per unit of land
William Laurence:
Tropical forest researcher, reported in 2011 that China was the biggest consumer of tropical timber
How much land area do tropical forests cover?
Tropical forests cover about 6% of the earth's land area; climactic/biological data suggests that mature tropical forests once covered at least 2 ties as much area as they do now today. Most of this loss of half the world's tropical forests has taken place since 1950
Rehabilitation:
Turning a degraded ecosystem into a functional one without trying to restore it to its original condition. Ex: Replanting a tree to reduce soil erosion in clear cut forests
Rangelands:
Unfenced grasslands in temperate and tropical climates that supply FORAGE, aka vegetation for grazing (grass eating) and browsing (shrub eating) animals
Industrialized/high-input agriculture:
Uses heavy equipment along with large amounts of financial capital, fossil fuels, water, commercial inorganic fertilizers, and pesticides to produce single crops or MONOCULTURES
Surface fires:
Usually burn only undergrowth and leaf litter on the forest floor. May kill seedlings/small trees but they spare most mature trees and allow most wild animals to escape
When does the degradation of tropical forests begin?
When a road is cut deep in the interior for logging and settlement. Loggers use selective cutting to remove the largest/best trees. When big trees fall, so do others because of the trees' shallow roots
