apes final chp 7, chp 9, chp 8

forestry & its impacts

cultivation of trees. methods such as clear cutting can lead to severe erosion, but alternative timbering methods have been created to reduce envionrmental damage

factors tht influence soil formation: topographical relief

steeper slopes promote runoff and erosion. hills and valleys affect the soil's exposure to sun, wind, and water, affecting weathering.

soil horizons: B Horizon

subsoil

fertilizers

substances that contain essential nutrients

farmer-centered agricultural resource management program (FAR)

supports innovative approaches to resource management and sustainable to agriculture internationally. this program was instigated by the UN

productivity factors

terrestrial environments: productivity increases w temp/precipitation. aquatic environments: productivity increases with light and nutrient availability

demography

the application of principles from population ecology to the study of statistical change in human populations. four factors affect Demography: population size, population distribution/density, age structure, and sex ratios

irrigation

the artificial provision of water to support agriculture. irrigation can boost productivity but causes long-term soil problems, through waterlogging and salinization

life expectancy

the average number of years that an individual in a particular age group is expected to live. average life expectancy has increased due to technological advances in medicine.

soil characterization: soil texture - general

the finer the particles, the smaller the spaces between them, so the harder it is for air and water to move in the soil. adversely, large particles allows water to pass through too quickly. so, medium size is the best.

sex ratios

the more even the gender ratios in a population, the better the growth rate. there is a naturally recurring ratio where there are slightly more boys than girls born; however, boys are more prone to death, so this ends up even in the end. an uneven sex ratio, however, like in CHina, lowers population growth rates. In China, specifically, there are more men than women, leaving many boys single. this has led to black market trade in girls

empowering women & how it affects growth rates

the more rights that women have, the lower fertility rates are in countries. for example, in countries where women have access to contraceptives and are in control of their own reproductive decisions, there are fewer children being have.

nitrogen cycle

the movement of N through environment. N makes up 78% of our atmosphere, and enters the other spheres through three processes

plate tectonics: two levels of the mantle

- harder, upper lithosphere - lower asthenosphere, where we drill for geothermal energy then we have heavy, molten core

hydrologic/water cycle (human impacts)

- we increase evaporations by damming rivers to create reservoirs - increase erosion/runoff by altering earth's surface and vegetation - reduce transpiration by cutting down forests - depleting groundwater sources

phosphorous cycle (detailed)

1. P is contained within rocks, only released as phosphate ions into water by weathering 2. phosphate ions then precipitate into solid form and sink to the bottom of these bodies of water, becoming sediment once again 3. in food webs, plants absorb P through their roots when dissolved in water and consumers absorb P from water and plants

eutrophication steps (5)

1. nitrogen input 2. phytoplankton flourish at surface 3. dead phytoplankton sink to the bottom, providing food for decomposers 4. decomposer population increases, causing their consumption of O2 to increase 5. now there's not enough O2, causing fish to suffocate at the bottom and creating a dead zone

carbon cycle (detailed)

1. producers pull CO2 out atmosphere and water to use in photosynthesis 2. photosynthesis breaks CO2 and H2O down into O2 and glucose, and release remaining CO2 back into the environment through respiration 3. consumers eat these producers and also release CO2 back into environment through respiration (breathing) 4. as organisms die, they get buried beneath layers of sediments, forming fossil fuels. fossil fuels can be released as CO2 through volcanic eruptions, uplift, and erosion

hydrologic/water cycle (detailed)

1. water moves from ground to atmosphere through evaporation, transforming liquid water into a gaseous form. warm temps and lack of vegetation speed up this process up. 2. water can also enter the atmosphere through transpiration, when plants release water vapor through their leaves 3. water returns to the earth as precipitation, when water condenses and falls as rain/snow. some is taken up by plants, most flows as runoff back into bodies of water 4. some water soaks down into aquifers, sponge like regions of rock/soil that holds groundwater. these take a long time to recharge

dust bowl

1930s USA, farmers over farmed their land, breaking down soil structure and causing erosion. the Dust Bowl itself happened when a drought exacerbated the human impacts on soil, and strong winds began to erode millions of tons of loose topsoil. dust storms ravaged the country, and some areas lost up to 10cm of topsoil

green revolution

1950; the green revolution introduced new technologies, crop varieties, and farming techniques. these dramatically increased crop yield per acre and helps millions avoid starvation; however, this also greatly increased soil degradation

conservation reserve program

1985; pays farmers to stop cultivating highly erodible cropland and instead replace it in conservation reserves

federal agricultural improvement and reform act

1996, this act is an extension of the Conservation Reserve Program. AKA the Freedom to Farm Act, this law aimed to reduce subsidies and government influence over farming products

pools

AKA reservoirs, pools are how nutrients move through ecosystems. they jump from pool to pool. how long they stay in said pool is called their residency time

HIV/AIDS impacts on Africa: demographic effects

African govs are currently experiencing demographic fatigue, meaning that they don't know what to do with their high growth rates and the amount of young people they have

Gulf of Mexico "Dead Zone" scenario

Gulf of Mexico is zone of great hypoxia, meaning that there is low concentration of dissolved oxygen. in 1991, dead zone maxed at more than 10,000 km^2. Many fish had fled, shrimp were stretching out their burrows searching for O2, and bottom waters were infused w sulfur from bacterial decomposition.

soil horizons

a horizon is a layer of soil. there are 6 horizons

demographic transition

a model of economic and cultural change. it explains the declining death and birth rates as nations have industrialized through 4 main stages. (in order): pre-industrial stage, transitional stage, industrial stage, post-industrial stage

systems

a network of relationships among parts that interact w and influence one another, exchanging energy, matter, and info. creates outputs and receives inputs.

industrialized agriculture

agriculture aided by large-scale mechanization and fossil fuel combustion. this intensified irrigation and introduced synthetic fertilizers. this also brought about monoculture, when large areas were dedicated to a growing a single crop

traditional agriculture

agriculture performed by human and animal muscle power, as well as simple tools and machines

soil characterization: soil texture - Loam

an even mixture of all three of these particles

correlation between poverty & population growth

areas tht are great poverty typically will have much higher growth rates than supposedly developed countries. the majority of the global population lives in developing countries, so people are being born into countries that unable to provide for them

deposition

arrival of eroded material at its new location

causes of soil degradation

as population and consumption rates expand, so does agricultural production. this causes environmental damage, as people struggle to farm enough food to feed the world. the soil just can't keep up

How did the Gulf of Mexico "Dead Zone" scenario happen?

as rivers rose each spring, and fertilizer were applied in Midwestern farm states, O2 would begin to disappear in the gulf. hypoxia would last until following winter or until seasonal storms mixed O2 back into the waters. size of dead zone depends on volume of river flow eg. larger the mississippi that yr, larger the dead zone. the fertilizer/agricultural runoff in river spurred algae blooms, by extension, Eutrophication.

Gross Primary Production (GPP)

assimilation of energy by autotrophs. autotrophs use this energy to power their own metabolism through respiration

soil formation

base of soil is parent material, which can include bedrock, sediment, volcanic ash or lava, and more. what affects soil formation, besides the fives reasons, is weathering, erosion, deposition and decomposition of organic matter

IPAT model

basically, I(total impact) = P (population size) x A (affluence and resource consumption) x T (technology as it allows us to exploit fossil fuels). Sometimes an S (sensitivity) is added in, measuring how sensitive a given environment is to human pressures.

factors affecting population growth

birth rates, death rates, immigration, emigration. nowadays, there is a much lower death rate than birth rate.

demographic transition: pre-industrial stage

both birth and death rates are high -- death rates because disease is widespread and birth because poeple need to compensate for high infant mortality rates by having lots of kids. populations in this stage are unlikely to experience much growth..

demographic transition: post-industrial stage

both birth and death rates have fallen to low, stable levels. population sizes stabilize or decline slightly

weathering: physical

breaks down rocks without triggering any sort of chemical change eg. rain or wind

salinization

buildup of salts in surface soil layers. water evaporating from lower horizons carries dissolved salts. when it evaporates at the surface, these salts precipitate. irrigation causes this because it increases the amount of evaporated salt that rises to the surface. to stop this, irrigate using water w low salt content or to not over-irrigate

ecosystems

consists of all biotic organisms and abiotic objects that occur and interact in a particular at the same time

factors tht influence soil formation: parent material

chemical/physical properties of the parent material influence its resulting soil

erosion

dislodging and movement of soil from one area to another. it occurs especially when vegetation is absent. this can help because nutrients can be deposited in an area where it was orginally lack nutrients; however it can be destructive by lowering the carrying capacity

protection of soils: reduced tillage

disturbs the soil more than no-tillage does, but it's essentially the same. it just prepares the soil a little more

positive feedback loop

drive a system towards one side of an extreme. (for ex, soil erosion along river banks causing trees to fall in. this causes the now loose soil, not held in place by roots, to fall into river, causing river to get even wider); super rare in nature but rrly common in systems altered by human impact

eutrophication

process of nutrient enrichment, blooms of algae, increased production of organic matter, and ecosystem degradation

nutrients

elements/compound that organisms consume and require for survival. nutrients simulate growth, which can or not be a limting factor depending where you are on the trophic level

soil horizons: E Horizon

eluviation/leaching level. leaching is when solid particles are dissolved in liquid, then drip down to E Horizon, taking the nutrients away from upper levels

Gulf of Mexico "Dead Zone" farmer's perspective

farmers challenged findings, saying tht Mississippi carries naturally high levels of nitrogen/nutrients. also said nutrients came not from farmers but from upwellings in gulf

protection of soils: terracing

for extremely steep terrain, farmers transform the slopes into a series of steps like a staircase. these steps are level platforms with raised edges to contrain water from precipitation/irrigation. it's very labor-intensive

soil conservation service

formed in 1935, when the US passed the Soil Conservation Act. the SCS works closely w farmers to develop conservation plans, and promoted soil conservation through conservation districts. these districts operate w federal direction and funding but are organized by the states. in 1994, the SCS was renamed the Natural Resources Conservation Service

sedimentary rocks

formed when dissolved minerals seep through sediment layers and act as a kind of glue, binding sediment particles together. this can happen chemically (limestone) or physically (conglomerate)

Net Primary Production (NPP)

generation of biomass. this is used with the energy leftover from respiration. in simpler terms, NPP = GPP - respiration; another way of thinking of it is that NPP represents the amount of energy left for heterotrophs to consume

family planning

government funding that encourages family planning can lower growth rates. for example, India encourages a two child norm, and Thailand on an education-based approach that has significantly lowered its growth rate

soil characterization: soil texture - Silt

has particles 0.002-0.5mm

soil characterization: soil texture - Sand

has particles 0.5-2mm. they do not adhere to each other

soil characterization: soil texture - Clay

has particles less than 0.002mm. they readily adhere to each other

population density

highest in tropical, subtropical, and temperate climates like China, Europe, Mexico, and India. Population density is lowest in extreme climates such as deserts and tundras. Populations are denser along the coast than further inland. at regional levels, we cluster around cities and urban hubs.

hydrologic/water cycle

how water flows through our environment. the ocean holds 97% of all water on earth. 1% of earth's water is readily available for human use

soil degradation by erosion

humans have increased the vulnerability of fertile soil to erosion through 3 practices: over cultivating field (tilling), overgrazing rangelands, and clearing forests on steep slope

age structure diagrams

if a diagram looks triangular, then the population will experience growth. if the diagram is an upside down triangle, then the population will decrease in size. a relatively even diagram means that the population is balanced

spheres

if earth is a system, than spheres are its parts. scientists have divided the system of earth in 4 diff components: lithosphere (rock/sediment), atmosphere (air), hydrosphere (water), biosphere (all biotic/abiotic elements)

demographic transition: transitional stage

increased food production and better medical care has decreased death rates. birth rates stay the same, so the populations during this stage usually surge in growth.

demographic transition: industrial stage

increased job opportunities lead to women working outside of the home. children become less economically valuable, so families have fewer and birth rate declines. this reduces population growth

soil characterization: soil color

indicates soil composition and fertility. the darker the color, the more rich it is in organic material. greyness/whiteness indicates leaching and low organic content

reducing erosion

it is common for people across the world to plant plants along riverbanks to anchor the soil, reducing erosion. farmers have also begun to maximize vegetation cover.

soil horizons: O Horizon

litter layer, where everything is decomposed

desertification

loss of more than 10% productivity due to erosion, soil compaction, forest removal, overgrazing, drought, salinization etc. Desertification can expand deserts and create new ones in once fertile regions. arid/semi-arid lands are esepcially prone to desertification due to low precipitation. currently, desertification affects one third of the planet

HIV/AIDS impacts on Africa

low rates of contraceptive use in Africa has led to the rapid spread of HIV/AIDS. 1 in 5 Africans have AIDS, and roughly 6k ppl die each day. those who die are in the 28-34 age group- the age group that works, raises the kids and is meant to be running the country. them dying has left children to fend for themselves, the economy to decline, and the country itself to be left blind.

soil structure

measure of soil "clumpiness". biological activity promotes structure, but too large clumps makes it hard for plant roots to take hold. however, the soil can't be too compact either, as repeated tilling causes plowpan - a hard layer that resists water and root penetration

soil pH

measures the degree of acidity/alkalinity. moderate (7) is the best

fluxes

movement of nutrients among pools, and rate of flux can change over time for various reasons. for example, the flux of nitrogen from the atmosphere to the earth has increased due to human activity

population growth - causes

new tech lead to better medical care, sanitation, and agricultural production, thus causing a decrease in death rates. more traditional causes include restrictions on women's rights -- eg. prohibitions on birth control - and a larger need for manual labor, leading to higher birth rates

rock cycle

process of rocks being heated, melted, cooled, broken down, and reassembled. at high enough temp., rock will enter a liquid, molten state called magma; Lava - magma spewed from lithosphere and onto earth's surface

plate tectonics

process that determines geography of earth's surface. earth's surface consists of a hard rock crust floating on top of a malleable mantle. the earth's internal heat creates convection currents, pushing against the mantle upwards as it warms and downwards as it cools, causes the crust to move in plates

lithification

process that forms sedimentary rocks; so dissolved minerals seep through sediment layers and act as a kind of glue to bind the particles together. similar processes create fossils of organisms.

nitrogen cycle: nitrogen fixation

nitrogen gas combines w hydrogen to form ammonia, which can be taken up by plants. can be accomplished in two ways: by an intense lightning strike or by nitrogen-fixing bacteria. these bacteria live on plants, providing them w nutrients by converting nitrogen into a usable form

macronutrients

nutrients needed in large amounts by organisms

micronutrients

nutrients needed in small amounts by organisms

convergent: type - oceanic subduction

occurs when an oceanic crust slides beneath a continental crust. this usually causes a volcano because the magma is directed towards the surfaces; e.g. the Andes

factors tht influence soil formation: organisms

organisms like earthworms mix the soil, add organic material, and facilitate microbial decomposition

human population growth

our world population currently grows by 80 millions people annually. our current growth rate 1.2%. we're currently growing exponentially, so soon we will have several billion people on this planet and not enough resources or space to hold them. the planet could theoretically support this through resource substitution but that doesn't ensure we maintain our current quality of life. to calculate a country's percent increase, the equation is (birth rate - death rate) / 10. the doubling time equation is 70/ the rate of increase

waterlogging

over-irrigated soils saturated with water. essentially, water bathes the plant roots, preventing them from accessing the gases needed to survive and suffocating them. if lasting long enough, this can kill them

hypoxia

oxygen deficiency in certain area

weathering

physical, chemical, and biological processes that break down rocks/minerals

protection of soils: intercropping

planting different types of crops in alternating bands. this reduces erosion by providing more land cover than a single crop does

immigration & emigration

plays a large role these days, especially due to refugee dilemma. 25 million refugees escape poor conditions each year, camping out in the wilderness can typically cause severe environmental damage before they find permanent homes.

protection of soils: contour farming

plowing furrows sideways across a hillside, perpendicular too its slope, to help prevent the formation of rills or gullies. these furrows acts as dams, catching runoff before it is carried away. this is because sloped land is especially vulnerable to erosion

sinks

pools w greater input than output

sources

pools w greater output than input

population growth - consequences

rapid population growth leads to denser populations, which in turn leads to greater amounts of war, disease, and conflict. it also leads to more agricultural production and resource extraction so as to provide for the larger population, damaging the environment. there is an increase in pollution due to higher usage of fossil fuels. the main 3 consequences, however, are summed up in economic loss, health impacts, and social disruption

productivity

rate at which production occurs. ecosystems whose plants convert solar energy to biomass really fast are said to have net primary productivity. for ex: tropical forests have a high productivity rate than deserts

food security act of 1985

required farmers to adopt soil conservation plans and practices in order to receive government benefits

soil horizons: R Horizon

rock layer/parent material

igneous rocks

rock that forms when magma cools

carbon cycle

route carbon atoms take through environment

wealth gap

so the wealthiest 20% of the global population consumes 86% of the world's resources, leaving only 14% for everyone else. wealth needs to be spread more equally in order for populations to stabilize

china's one-child policy case study

so when China was founded, its population began to grow exponentially. by 1970, the population had grown to 790 million people, with the average chinese woman giving birth to 5.8 kids in her lifetime. unfortunately, china wasn't employing sustainable food production methods, and the gov realized they wouldn't be able to support their growing population. they instituted a population control program. first, they encouraged people to marry later and have fewer children, increasing the availablity of contraceptives. by 1975, the annual growth rate had decreased from 2.8% to 1.8%. 1979, gov instituted a punishment and rewards system. one child families received better schooling healthcare, job opportunities. families w more than one child faced discrimination and monetary fines. today, the one child policy applies mostly to urban couples while rural families are largely exempt. the annual growth rate is down to 0.6%. the cons, however, are an unbalanced sex ratio due to the widespread killing of female infants (male children to better in CHinese workplace). this lack of females has led to a black-market trade in teenage girls. the policies have also been criticized for intruding into personal reproductive choices.

factors tht influence soil formation: time

soil formation take decades. all factors that influence soil formation changes soil formation very slowley

factors tht influence soil formation: climate

soil forms faster in warm, wet climates. heat accelerates weathering, decomposition and biological growth

agricultural uses of soil

soil is a critical part of successful agriculture and the original gangster of sources from which we grow our crops. nutrients from soil goes to plants, plants goes to animals, we eat the animals/plants etc.

protection of soils: shelterbelts

the planting of trees or perennial plants along the edges to fields to slow the wind. when combined w intercropping, this is called alley cropping

phosphorous cycle

the route phosphorous atoms take through the envionrment. unlike carbon and nitrogen cycles, phosphorous does not cycle through atmosphere

population distribution

there is an uneven distribution of the population, w people clumped around cites and coasts. this means certain areas have exert higher environmental pressure than others. areas w less people are also prone to environmental pressures though, as the reason no one lives there is usually because that environment is too sensitive to support life

fertilizers: inorganic vs organic

they are mined or synthetically manufactured, and organic, which consist of organism waste or remains

swamplands act

this act provides a way for federally owned land to be given to the state w the assurance that the land will be used to farm and be productive

soil characterization: soil texture

three categories of soil texture, determined by size of particles

fertilizers: what happens when too much

too much fertilizer, however, can lead to excess phosphorous or nitrogen, increasing surrounding runoff and pollution eg. the mississippi river and the dead zone

soil horizons: A Horizon

topsoil, the most nutritive level for plants and vital for agriculture

TFR

total fertility rate is the average number of children born per female of a population during her lifetime. urbanization and government social secuirty has lowered TFR in recent years, as parents no longer neeed their children as labor and to look after them. also, women are no longer required to focus on raising children -- they now work also. in Europe, the TFR dropped from 2.6 to 1.5

ecotones

transitional zones where ecosystems meet. this means elements from both ecosystems mix

invention of agriculture

until 10k yrs ago, humans were hunter-gatherer types. agriculture started bc these hunter-gatherer brought fruit, grains, and nuts back to their camps. some of these fell to the ground, growing and producing fruit that were tastier than those found in the wild bc their seeds had been selected specifically by the hunters for their taste. eventually, people realized they could selectively breed through this process, and began intentionally planting crops. estimated to happen first in the Fertile Crescent in the middle east 10,500 years ago, although there is evidence that 5 diff cultures began doing it at the same time separately. people in the crescent also began domesticating animals, such as goats and sheep

soil horizons: C Horizon

weathered parent material

metamorphic rocks

when a rock changes form due to great heat or pressure. this occurs at temps lower than the rock's melting point but high enough to reshape crystals within the rock eg. marble (formed by limestone)

feedback loops

when a system's output can also serve as its input, like a continuous circle of energy.

non-tilling

when a tractor pulls a no-til drill that cuts furrows through the O Horizon, dropping seeds into it then closing it up. this disturbs the soil less. non-tillage conserves biodiversity, produces high crop yields, and reduces fossil fuel usage

primary production

when autotrophs convert solar energy into the energy of chemical bonds in sugars

nitrogen cycle: denitrification

when bacteria convert nitrates in soil or water into gaseous nitrogen

protection of soils: crop rotation

when farmers rotate the type of crop grown in a field from one season to the next. this returns nutrients to the soil as different crops take different nutrients, as well as reducing the erosion that comes with fallow fields

weathering: biological

when living things break down the parent material through physical or chemical means eg. lichen produce acid, which chemically weathers rock

igneous rocks: intrusive rock

when magma cools slowly while it is still below surface eg. granite

igneous rocks: extrusive rock

when magma is ejected from lithosphere and cools, giving little time for mineral to differentiate into clusters eg. basalt

divergent

when magma surges up and pushes plates apart, creating a new crust as it spreads and cools eg. the mid-atlantic ridge

traditional agriculture: type - intensive traditional agriculture

when people aim to produce excess food so that they can sell it and make money

traditional agriculture: type - subsistence agriculture

when people produce only enough food to feed themselves.

convergent

when plates collide

splash erosion

when raindrops dislodge soil particles, decreasing soil's ability to absorb water

gully erosion

when rills merge to form larger channels, called gullies. gullies cut deeply into the soil, expanding as erosion proceeds

nitrogen cycle: nitrification

when specialized bacteria convert ammonium ions into nitrite ions and then into nitrate ions. plants then take up these ions, and animals get them by consuming the plants

negative feedback loop

when the output and input neutralize each other's effects, stabilizing system. (for ex, when you're hot, you sweat. when you're cold, you shiver)

convergent: type - continental convergence

when two continental plates collide and uplift, creating mountains eg. the Himalayas

transform

when two plates slide/grind against each other, creating friction and earthquakes eg. San Andreas fault

sheet erosion

when water flows in thin sheets over broad surfaces, washing away topsoil

weathering: chemical

when water or other substances chemically interact w the parent material

rill erosion

when water runs along in small furrows, deepening them and widening them into channels called rills

tilling

when you prepare/cultivate the ground (eg. ploughing) in preparation for crops

empowering women & how it affects growth rates

while most nations have a contraceptive use percentage above 50%, African nations have below 10%. these women have little freedom and education, and a substantial number of pregnancies are left unattended.

empowering women & how it affects growth rates

women and men need to be equals in order for population growth to slow and stabilize