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ENSC study guide Slattery TCU

Terms in this set (42)

Biodiversity
-variety of life on Earth and the natural distribution of patterns and organisms
-result of billions of years of evolution shaped by natural processes and the influence of humans
-humans are fully dependent on the intricate web of life to sustain the human species
-made up by species richness (measures diversity) and species evenness (rareness of species)
how many species have been identified?
1.58 million
why is biodiversity important?
-our survival depends on it;species depend on one another to keep species in check and support them
-economic and environmental benefits of biodiversity estimates at $319 billion a year
-ecosystem with high diversity is healthier
-provides medicines, food, and energy by maintaining ecosystem functions
what causes high diversity zones?
-areas in the tropics have abundant rainfall and warm temperatures year round so ecosystems here are highly reproductive
-year round dependability of food, moisture, and warmth supports great exuberence of life and allows for a high degree of specialization in physical shape and behavior of species
-latitudinal diversity gradient
biodiversity hotspot
what is a hotspot?
-areas featuring exceptional concentrations of highly vunerable species and experiencing loss of habitat
-must contain 1500 plants and endemics (irreplaceable)
-must have lost at least 70% of original habitat (30% currently threatened)
-currently 34 hotspots (2% of Earths land area)
-Mesoamerica hotspot-forest here are the 3rd largest in the world
-Madagascar-10% of all known species
Latitudinal Diversity Gradient
decrease in diversity from the tropics to the poles
background extinction
background-constant rate of extinction throughout geological time
-estimate that species live 10 million years before going extinct
-accounts for 95% of all extinctions
- btw 0.0001 - 0.00001% per year or 0.01%-0.001% per century due to natural causes
anthropogenic extinction
anthropogenic-extinction due to human activity
-3400 plant species, 5200 animal species, and 1/8 bird species face extinction
-before: 1 mammal species extinct every 400 years & 1 bird species every 200 years--now: 10,000 times that (20-75 plant/animal species every day)
threatened species
population low but extinction less imminent
endangered
numbers so low that extinction is imminent

characteristics
-small (localized) range
-extensive range but significantly modified by humans
-Island dwellers (limited immigration, isolation from competition, predators, and disease--so few defense when introduced)
-specialized habitat or diet
-low reproductive rates
-slow moving or large easily hunted animals
-perceived value
rates of deforestation
5.6 million hectares being lost annually
-South America and Amazon have 30% deforestation
-global deforestation 1% a year
Drivers of deforestation
underlying causes or motivations
-poverty and overpopulation
-market failures, property rights, uneven land distribution, ect.
-gov policies to encourgage econ development (roads and railway expansion)
agents
direct causes
-individuals, corporations, gov projects that clear forest
-biggest agent: conversion to cropland and pasture
subsistence farmers
landless people who follow roads into already damages areas and establish small scale farming operations
-slash and burn ag (swidden ag)-chop down and burn tree trunks
-60% deforestation
-rapid decline in soil productivity
commercial logging
-21% deforestation
-ranked biggest cause of tropical deforestation
-clear cutting (all trees cut) or selective logging (environmentally sensitive alternative)
cattle ranching
12% of deforestation
-aided by government subsidies
why are forest important?
-act as carbon sink and contain most of the worlds species
-act as habitat for many species
-system regulators: moderate air temp, regulate humidity levels, regulate stream flow
-forest canopy protects from soil erosion
-absorbs CO2, generates oxygen
-important sources of new pharmaceuticals
-food and shelter
-role in religious and cultural traditions
herringbone
more disruptive to environment, more edges, more natural wildlife disturbed
-increases perimeter of disturbance to living species
-easier to isolate areas of land because there will be small "islands" of forest in the middle of massive clearings
clear cut
less destructive, perimeter is one continuous ling, harder to isolate
edge effects
more fragmented in Herringbone`
biological corridor
passes through which species can move from reserve to reserve without crossing human dominated landscape
-connects fragmented reserves, allows migration, increases chance of survival
soil
unconsolidated mineral of organic matter on surface of Earth
-recycling system for nutrients and organic wastes
-habitat for soil organisms
-system for water supply and purification
-engineering medium
-medium for plant growth
soil formation
changes with in loose broken down rock (parent material) overtime into horizons (layers)
1. Additions-organic matter added as organic matter falls onto top layer
2. Removal- uptake from plants removes ions and erosion removes ions, particulates, and organic material
3. Translocation- ions, humus, compounds, and clays get moved down the soil profile; ions move up the soil through capillary action
4. Transformation-leaf litter and other organic material is transformed by soil macro and micro invertabrates into humus; minerals transformed through chemical weathering
soil formation formula
f(c, o, r, p, t)
c=climate, o=organic matter, r=relief, p=parent material, t=time
soil horizons
O-surface litter: fallen leaves and partially decomposed organic debris
A-topsoil: organic matter (humus), living organisms, inorganic materials *most important bc supports vegetation "root zone"
E-Zone of leaching: dissolved or suspended materials move downward
B-subsoil: accumulation of iron, aluminum, humic compounds, and clay from A & E
C- weathered parent material: partially broken down inorganic materials
R-bedrock: impenetrable layer
2 major soil types in the US
Mollisol- productive agriccultural soil underlying the breadbasket of US
-soft & fertile, 25% of US soil
-10 inches thick
Utisol- low and moderately fertile, acidic, 12.8% of US soil
land degradation
occurs when soil deteriorates because of human activities and loses its quality and productivity
-characterized by loss of nutrients and organic matter, breakdown of soil structure and high toxicity from pollution
how much soil we lose
1982-3 billion tons/year (18 tons/ha)
2007- 1.8 billion tons/year (12 tons/ha)
12 tons of soil eroded per year (spread out equals .04 in)
T Value
amount of soil you can afford to lose
-depends on ho much soil you have to begin with
-ranges from 2-11 tons/ha/year
11=maximum limit
soil loss vs soil formation calculation
-takes 500 years to form 1 inch of topsoil
-requires 6 in topsoil to grow good crops
-12/ha lost per year (.o4 of an inch)
-takes 28 years to lose 1 inch of topsoil
*500/28=18 (soil is being depleated 18 times faster than it is being built up)
ecological footprint
how you ind. impact the environment
-measures how fast we consume resources and generate waste
-compare to how fast nature can absorb our waste and generate new resources
-includes water, energy, food, and products we consume
-created to measure sustainability
water compartments
all the water on earth
-98% salt
-2% fresh
~87% snow and ice
~13% liquid water
---95% groundwater
---3% lakes, rivers, streams
---2.5% soil moisture
(drinkable)
aquifers
confined- water is under pressure between 2 confining layers of low permeability

unconfined-water table defines the upper surface of the aquifer; nothing limiting the water from infiltration and recharging the water table
water use data
each person in US uses 155 gallons per day but only needs 5
>thermoelectric power-49%
>irrigation- 31%
>public supply- 11%
>industrial- 4%
>aquaculture- 2%
>mining- 1%
>domestic- 1%
>livestock- less that 1 %
point source pollution
point source-pollution discharges through a pipe or some other discreet source from municipal water treatment plant, factories
-refers to effluent being releases from a single outlet, meaning it is easier to monitor and control
non point source
pollution discharges over a wide land area, not from one specific location
-refers to pollution that cant be linked directly to one specific source, such as when runoff picks up pollutants from agricultural fields and deposits them into rivers, ales, costal water, or groundwater
diffuse pollution caused by sediment, nutrients
why is sediment a pollutant
-makes water murky (turbidity) and reduces photosynthesis but blocking sun for plants
-decrease in DO in the water
-dredging to remove sediment cost $1 billion a year
-erosion types
>sheet, rill, stream bank, mass movement
oxygen sag
-occurs downstream from an organic source
-decomposition of material requires high oxygen
-oxygen goes down as oxygen is consumed by bacteria from decomposition
oxygen sag
demographic transition
-death rates fall
-then birth rate slowly lowers
-total population increases
rhino crisis
being poached because
-the ferrari factor
-use of ground up horn in Asian medicine
-"party drug"
-"viagra of the east"
>horn fetched
$65,000-$100,000/kg --- each
horn 3-4.5 kg
>for poor people in Africa this is a fortune so they kill rhinos for their horns

why should we care?
-about to go extinct
-experience extremely painful deaths
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