Science Section 3 - Part 1 Flashcards
(128 cards)
1
Q
What is
Growth Rate
A
Percentage change of a population; depending on births, death, immigration, and emigration
2
Q
What is
crude birth/death rate
A
The number of births/deaths per 1000 people
3
Q
What are
higher-income countries
A
Europe, North America, etc.—comprising 1.3 billion people.
4
Q
What are
lower-income countries
AKA less-developed
A
Haven’t or still are industralizing—comprises 6.7 billion people
Includes China and India
5
Q
How has the population difference between more- and less-developed countries changed?
A
Populations in less-developed countries have continued to grow rapidly (~1.5%), while richer countries’ have almost leveled off (~0.2%)
6
Q
What is
environmental degradation
A
Pollution and other disturbances to the environment, human & natural
7
Q
What contributes to environmental degradation?
A
The extraction, processing, use, and disposal of human-used resources
8
Q
What is
environmental impact
A
The population ✕ Resource use per person ✕ The impact of the resource
9
Q
How has energy use changed over time?
A
Energy use has increased at a greater rate than population growth.
10
Q
What was the population and fossil fuel consumption in 1960?
A
- 3 billion people
- 3,000 million tons of oil equivalent
11
Q
What was the population and fossil fuel consumption in 1999?
A
- 6 billion people
- 7,900 million tons of oil equivalent
12
Q
What was the population and fossil fuel consumption in 2022?
A
- 8 billion people
- 11,500 million tons of oil equivalent
13
Q
How has energy use changed over time?
A
Energy use has increased at a greater rate than population growth
14
Q
What is
fertility rate
A
The average number of children born to each woman through her child-bearing years, in a population
15
Q
What is
replacement fertility rate
A
The average number of children per woman required to replace a population (maintain population levels); around 2.1
16
Q
What is
life expectancy
A
Years expected to live of an infant born in a given year
17
Q
How does life expectancy differ between men and women?
A
Women generally live longer than men, due to lifestyle choices and dangerous workplaces; gap is decreasing as women enter the workforce.
18
Q
What is
infant mortality
A
The number of deaths of infants (age<1) per 1000 births
19
Q
Does the USA 🇺🇸 have the lowest infant mortality?
A
Canada 🇨🇦, Finland 🇫🇮, Iceland 🇮🇸, Ireland 🇮🇪, Japan 🇯🇵, Sweden 🇸🇪, and France 🇫🇷 have rates 1–2 deaths per thousand lower than the US, which spends more per capital on healthcare.
FALSE. FALSE. FALSE. FALSE. FALSE. FALSE. FALSE. FALSE. FALSE.
20
Q
How can you measure the level of healthcare of a country?
A
Life expectancy and infant mortality; NOT crude death rate, because that is a reflection of age (e.g. mexico (5) vs USA (9))
21
Q
Why does US 🇺🇸 infant mortality differ from comparable countries?
A
- No Universal Healthcare
- Less generous time off
- Disparity in healthcare for minorities
22
Q
What is the
%<15/%>65 figure
A
Percent of the population younger than 15
vs.
Percent of the population older than 65
23
Q
What is an
age structure diagram
A
A chart showing a population divided by age groups and gender, representing age distribution.
Brainscapes charges to add images. Google it.
24
Q
What is a
population pyramid
A
A pattern appearing in lesser-developed countries, where fertilty rate is high; there are lots of young people, so the age-structure diagram looks like a pyramid.
Older countries get an inverse pyramid. Stable populations are columns.
Google it.
25
What are the **layers** of the Earth?
* The dense **core**
* The **mantle** (80% of volume)
* The **crust** on top
26
What is the **distribution of iron** in the Earth?
The whole Earth is **35%** iron, while only **6%** of the lithosphere is iron.
27
# What is the
**lithosphere**
The first **100km** of rock, where the rock cycle occurs and soil gets elements from; includes the crust and outer mantle
28
What are the **elements** of the **atmosphere**?
1. Nitrogen (78%)
2. Oxygen (21%)
3. Argon (0.9%)
4. CO₂ (0.036%, trace gas)
29
# What are the
**building blocks of life**
* Carbon
* Hydrogen
* Oxygen
30
# What are the
**macronutrients**
`>`0.1% of dry weight:
* Nitrogen
* Phosphorus
* Potassium
* Calcium
* Sulfur
* Magnesium
31
# What are the
**micronutrients**
`<`0.1% of dry weight:
* Manganese
* Iron
* Copper
* Zinc
* Molybdenum
* Chloride
* Boron
32
# What is the
**aqueous phase**
A chemical form of an element that can **dissolve in water** (necessary for plants)
33
# What is
**soil water**
The water in **pore spaces** between soil particles that faciliate element exchange
34
What does **weathering** do?
Physical/chemical breakdown that **releases elements** from mineral rock
35
What does **erosion** do?
Moves elements around via wind/water
36
How is **weathering** accomplished?
* Water
* Wind
* Acid Rain
* Other chemicals
* Roots of growing plants
37
Where are **calcium**, **magnesium** and **potassium** derived from?
Primarily rocks and decomposed vegetation
38
What **rock types** do **calcium** and **magnesium** occur in high concentrations?
**Limestone**, **dolomitic limestone**, and **marble**
39
What **ecosystems** are **calcium** and **magnesium** found in?
Those overlying **limestone** and some other rock type
40
What **elements** did the **dust storms** of the '20s and '30s **carry**?
**Calcium** and **magnesium**, carried westerly into the central and eastern states
41
What **caused** the **dust bowls** of the '20s–'30s?
The **topsoil** was **destroyed** by:
* Heat
* Drought
* Wind
* Poor agricultural practices
* Other human land use
42
What is the **gaseous** component of **sulfur**?
Sulfur dioxide, SO₂
43
What form of **sulfur** do **plants** take up?
The **sulfate anion**, SO²⁻₄; also comprises **acid rain**
44
What is a natural **atmospheric** source of **sulfur**?
**Volcanoes**, which release the natural pool of sulfur in rocks and mineral
45
# TRUE OR FALSE
**Sulfur** deposition is *higher* than that of **nitrogen**
***TRUE!*** Although air regulations have decreased it since 1995 in the US 🇺🇸
46
# TRUE OR FALSE
**Sulfate** does *not* **leach** easily from **soils and ecosystems**
***FALSE!***
47
What are the **benefits** of **soil**?
* Plants grow in it
* Filters water
* Bacteria, fungi, disgusting insects, other animals live in it; some very important decomposers
* Filter some air/sewage pollution
* *Bonus*: Food. Be grateful.
48
# What are
**soil horizons**
Layers of soil distinguished by physical/chemical/biological factors
49
# What is the
**O horizon**
Specifically the **top layer in forests**, consists of needles, leaves, woody material, animal bodies, animal droppings.
50
# What is the
**A horizon**
Usually the **top layer**, consists of **humus** (organic material) and **mineral** soil that has been mixed together, by animals/plants/humans.
51
# What is the
**E horizon**
**Only exists in more acidic soils**; chemicals have **leached** out, and is left **light in color**. Below the O or A horizon.
52
# What is the
**B horizon**
Where **chemicals accumulate** from the O, E, and A horizons, along with elements that weathered in place. **Always exists**.
53
# What is the
**C horizon**
**Least weathered**, **always occurs** below B horizon. Similiar to the **parent material** (original soil material). Contains **roots/microbes in humid regions**; otherwise they extend only into the B horizon.
54
# What is
**humus**
**Organic** material in the soil from **plant and animal matter**
55
# What are
**state variables** (soil)
The factors that **cause soil to progress** and **determine its nature**:
* **Parent material**
* **Climate**
* **Topography**
* **Organisms**
* **Time**
56
# What is
**bedrock**
The **solid rock** underlying the soil. Usually **synonymous with parent material**; not when e.g. glaciers have spread a layer of sediment on top of the bedrock, separating the parent material.
57
# What is
**parent material**
The **original rocky material** from which the soil is derived; a **state variable** that determines the nature of the soil.
58
How does **climate** affect **soil formation**?
A **state variable**; the sum of weather-related variables over time:
* **Temperature** increases *weathering* and *soil formation*
* **Freeze-thaw cycle** increases *surface area for weathering*
* **Precipitation** (also causes *weathering*) and **temperature** increases *leaching*
* Also influences the *type of vegetation*, and the *rate of decomposition*
59
How does **topography** affect **soil formation**?
The **surface configuration** of a landscape; a **state variable**:
* Soils on **steep slopes** face *erosion* and *landslides*
* **Landslides** are hazardous to *soil, ecosystems, and people*
* **Horizontal soils** & those at the **bottom of mountains** tend to *accumulate material*
* **Windward sides** of mountains have more *precipitation* than the leeward sides
## Footnote
*"Despite these well-known dangers, people continue
to build on such soils—often quite expensive structures—and seem surprised when they are destroyed."*
60
# What are
**detrivores**
Organisms that consume dead plant and animal matter
61
What **organisms** account for **80–90%** of biological activity in **soils**?
These eat plants (dead&alive), + animal waste (detritus); majority are **detrivores**. Bacteria **liberate nitrogen & sulfur** from the soil for plants to use.
* **Fungi**
* **Bacteria/Archaea**
* **Protozoa** (single-celled organisms, e.g. algae)
| (detrivores: consume dead plants and animals)
62
How many more **detrivores than herbivores** are there in the **first 15cm of soil**?
There are **10 times as many** detrivores than herbivores.
| (detrivores: consume dead plants and animals)
63
In the **temperate** zone, what is the most important **macrofauna**?
| (Macrofauna: *Large (relatively speaking) animals*)
***Earthworms*!**
They can ingest 2–30 times their weight in soil every day! Also they:
* Extrete nutrient-rich organic matter, which improves soil quality
* Aerate the soil
* Improve water drainage
* Mix upper and lower layers of soil
* Are sensitive to acidic soil; do best in neutral pH
64
How does **soil** change over **time**?
**Time spent unfrozen** influences soil development:
* **New soil** has **very little separation into different horizons**
* Soils **develop horizons** and characteristics **over time**
* Grassland soils in e.g. the Great Plains have very **thick and nutritious** and delicious **A and B horizons** that developed over **hundreds of thousands of years**
65
# What is
**soil degradation**
The **loss** of some or all of a soil's **ability to support plants**
66
# What is
**topsoil**
Soil of the **A or O** **horizons**; can take **centuries to replenish**
67
What are the **causes** of **soil degradation**
* **Erosion** which carries away disturbed (by e.g. plowing) topsoil by water or wind
* **Compaction** from machines
* **Nutrient depletion** from intensive use
* **Irrigation**
* **Chemical damage** from e.g. pesticides
68
How has **soil degradation** affected the **world** today?
**Worldwide**, there has been a **17% reduction in food production**, most prevalent in **Africa and Europe**
69
How is **climate change** affecting **soil degradation**?
* **Slightly warmer** temperatures may **increase** decomposition
* But **dryer** soils may **slow** decomposition
70
# TRUE OR FALSE
Soil in areas of **extreme temperature/precipitation** recover from **soil degradation** *slowly*.
***TRUE!***
71
How much water is **fresh water**?
**3%**, most of which is in ice—only **1%** of all water is potentially usable by humans and terrestrial organisms
72
How much of Earth's water is in **lakes, rivers, reservoirs**, the **atmosphere**, and **within organisms**?
* only **0.009%** in lakes, rivers, and reservoirs
* perhaps **0.001%** in the atmosphere
* less than **0.0001%** within organisms
73
# What is an
**aquifer**
**Permeable** layers of **rock and sediment that hold water**
74
# What is an
**unconfined** aquifer
An aquifer of **porous rock** (such as **sandstone** or **other consolidated sediments**) **covered simply by soil**.
75
# What is the
**water table**
The **top** of the area within an aquifer **saturated with water**
76
# What is an
**aquiclude**
An **impermeable layer of clay** that stops groundwater flowing from an aquifer; **confines** the aquifer
77
# What is a
**confined** aquifer
An aquifer confined from **above and below** by an **aquiclude**
78
# What is an
**artesian well**
A well drilled into a **confined aquifer**, which can have water flow **without needing a pump**
79
What is one type of **surface water** that is **fed by groundwater**?
A **spring**; a small stream that "springs" out of an aquifer during wet seasons.
80
What are the problems introduced by constructing an **aqueduct** in a **desert/grassland?**
* Vegetation is disrupted
* Soils are disturbed
* Animal habitats are altered or destroyed
81
How much water is lost due to **leakage** from old or damaged pipes in **Jordan and the Occupied Territories of Israel?**
As much as **55%**
82
Countries from the **Middle East and North Africa** are responsible for how much of the world's **fresh water produced through desalination?**
More than **50%**
83
How is water desalinated through **distillation**, and what is its downside?
Water is **evaporated**, leaving behind salts; the steam is then **condensed**, producing pure water. This is, however, a **highly energy intensive** process.
84
How is water desalinated through **reverse osmosis**, and what are it's benefit and downside?
Water is **forced through a membrane**; the water passing through is very pure, and that left behind is **highly salty** **brine.** This is **cheaper and more efficient** than distillation, but brine released into the ocean can **impact local ecosystems.**
85
In 2023, how much water was used in the **US 🇺🇸?**
**408 billion gallons per day**, or **1,300 gallons per person per day**
| Lower water use in most other countries
## Footnote
This includes domestic use, commercial and municipal use, irrigation for agriculture, and cooling for electrical power plants.
86
How much of **worldwide food production** benefits from **irrigation**?=-
**40%**
87
How much water does it take to produce **one ton of grain**?
**1,000 tons**
| (250,000 gallons)
88
# What is
**conventional** irrigation
Water runs through a ditch alongside crops; **60%** efficient
89
# What is
**drip** irrigation
A tube buried in the ground releases water slowly; **95%** efficient, but more expensive.
90
What is the effect of **prolonged droughts** on soil?
Can dessicate the soil to such an extent that the **topsoil blows away**; Land **can't be farmed for decades**; Subject to **erosion from flooding**, as it can no longer absorb much water
## Footnote
des·ic·cate
/ˈdesəˌkāt/
verb
remove the moisture from (something); cause to become completely dry.
91
What happens to an **aquifer** during a **drought**?
During droughts, aquifers **usually contain some water**. If an aquifer is overpumped though, it can be depleted, which may result in wells going dry.
92
What happens when a well **next to a coastline** is **overpumped**?
Nearby saltwater will be drawn into the aquifer, saltifying the water in a process known as **saltwater intrusion**
93
What are two **recent** major **floodings**?
* West Bengal, India (2000) — destroyed **>800k homes**, killed **hundreds of people**
* Worldwide flooding in **2023**, driven by increasingly intense storms
94
What are the environmental benefits of **floods**, **hurricanes**, and **torrential rains**?
When water overflows a river's banks, **nutrient-rich sediment** improves the soil quality
95
How many people do *not* have access to **safe drinking water**?
1–2 billion people, most in the developing world
96
# What are
**point** sources
A **distinct**, confined source of pollution
| (such as a sewage pipe, or factory)
97
# What are
**non-point** sources
A **diffuse** (spread out) area from which pollution originates
| (such as a parking lot, or farm)
98
How can pathogens **contaminate** water?
* Malfunctioning **sewage treatment/septic systems** (point)
* **Wildlife** (non-point)
99
What pathogens are common in the **US** 🇺🇸?
* **Hepatitis A**, originating in unclean restaurants
* The bacterium ***Cryptosporidium***, which has caused outbreaks of gastrointestinal illness
* The parasite ***Giardia***, which has been transmitted into mountain waters by hikers
100
# What is
**oxygen-demanding waste**
**Organic material** in water (like leaves and twigs) that attract **decomposing bacteria which deplete the oyxgen levels** of the body of water
101
# What is
**biochemical oxygen demand (BOD)**
A measure of **oxygen-demanding waste**—the amount of oyxgen used over (usually) 5 days at (usually) 20℃ in a certain amount of water. Lower numbers mean more pristine water.
## Footnote
Sewage may have 200 mg of BOD per liter of water; natural water may have 5–20.
102
How do different amounts of **dissolved oxygen** (in ppm, parts per million) affect ecosystems?
When dissolved oyxgen is *high*, BOD is *low*—and vice versa.
**8–9ppm is high quality** and ideal for aquatic ecosystems. **~4ppm is polluted**, where fish have trouble functioning.
103
# What is
**eutrophication**
The **excessive growth** of algae due to an **oversupply of nutrients**; when the algae dies, **BOD increases** sharply and **the fish population suffocates**.
104
How does **nitrogen and phosphorus** enter bodies of water?
Nitrogen: **farm runoff, sewage treatment, acid precipation**
Phosphorus: **naturally occuring rocks and minerals, fertilizer,** and in the past, **detergents**.
105
What **metals** are among the **most toxic water pollutants**?
* **lead**
* **copper**
* **arsenic**
* **mercury**
106
What is the US 🇺🇸's largest source of **mercury emissions**?
**Coal- and oil-fired power plants** that deposit it on land and in waterways
107
How does **inorganic mercury** (Hg) become **methylmercury**?
In wet, **anaerobic** environments such as wetlands, aquatic sediment, and temporarily saturated soils, **bacteria convert** mercury to methylmercury.
## Footnote
an·aer·o·bic
/ˌanəˈrōbik/
adjective
relating to, involving, or requiring an absence of free oxygen.
"anaerobic bacteria"
108
How is **methylmercury** toxic to humans?
Damages the central nervous system, including coordination and the senses of touch, taste and sight, especially in embryos and small children
109
# What are
**persistent organic pollutants** (POP)
Toxic, industrial chemicals that persist for **decades or longer**, accumulating in organisms throughout food webs.
110
# What are
**PCBs** (polychlorinated biphenyls)
Highly **toxic and carcinogenic**, they were used in plastics and insulation **until 1979**; they are still present today.
111
What was the cause of **PCB pollution** into the **Hudson River**?
A **General Electric** plant.
112
What was done to clean up the **Hudson River** of **PCBs**?
The EPA ruled in 2002 that General Electric must pay for the dredging and removal of PCB-contaminated sediment from the river bed. Under a 2006 agreement, dredging began in 2009 and finished in 2015; it is still monitors for developments.
113
What are sources of sediment that pollute water?
* Housing & shopping development
* Agriculture
* Dam construction (sediment accumulates in unmoving water; runs downstream when mobile again)
114
How does **sediment water pollution** affect **ecosystems**?
Sediment can **clog fish gills** and otherwise **impede oxygen intake**, particularly in bottom feeders (oysters, clams). Also stops sunlight, decreasing primary productivity.
115
What causes **thermal pollution** in water?
* When water moves slower
* When water receives more sunlight
* When water enters a shallower waterway
* When used for cooling in industrial areas and power plants
| (all humans causes)
116
How does **thermal pollution** in water affect **ecosystems**?
* **reduces the possible amount of dissolved oxygen**
* **Increases the respiration of organisms**, further reducing dissolved oxygen
* Stresses organisms, making them **more susceptible to disease**
* May also **affect reproduction**
117
What is the most notorious recent **oil spill**?
The **Deepwater Horizon** spill of 2010 in the Gulf of Mexico, which had **210 million gallons** of oil cover ocean and coastlines, deeply impacting local ecosystems; cleanup continues to this day
118
What are the **cleanup methods** of the **Deepwater Horizon** oil spill?
* **Floating booms** to prevent oil from spreading
* **Skimming** oil off the water's surface
* **Chemical dispersants** that break down oil until it's small enough to be destroyed by sunlight and bacteria
119
What are the sizes of **microplastics** and **nanoplastics**?
Smaller than **5mm** and **0.0001mm** respectively
120
# What is
**gray water**
**Wastewater that is *not* from toilets**, like from sinks or showers; can be used without treatment for e.g. watering lawns
121
Properties of **sewage**?
* High BOD
* Pathogens
* High levels of nitrates and phosphates
122
How is sewage decomposed?
1. Bacteria break down organic matter into CO₂ and inorganic compounds like nitrates and phosphates
2. Dissolved oxygen levels are reduced in the water
3. Eventually, BOD goes down, and oxygen levels recover
## Footnote
Sewage treatment plants replicate this process (usually quicker)
123
# What is
**primary treatment**
**Removal of 40–50% of solid waste material** from sewage; becomes **sludge**
124
# What is
**sludge**
**Solid material** from primary treatment that has **settled and dried**
125
# What is
**secondary treatment**
**Acceleration of the natural breakdown of organic matter** in sewage; by the end, roughly **85–90% of original pollutants have been removed**. After disinfection, the water can be released into a body of water to join the water cycle.
126
What is the history of **water quality** in the US?
| 🇺🇸?
* 40–50 years ago, harbors and waterways were badly polluted
* the Clean Water Act (passed 1972 and amended since then)
* the Safe Drinking Water Act of 1986
* the Water Resources Development Acts (1986–92)
127
What did the **Clean Water Act** (1972) accomplish?
* establishment of **Water Quality Standards** that limit the concentration of specific pollutants in major bodies of water
* to achieve these Standards, established a **Total Maximum Daily Loads** for each pollutant—the maximum amount of each that can be discharged from any point or non-point source
128
What did the **Safe Water Drinking Act** (1986) establish?
Established **maximum containment levels** (MCL) for 77 different elements or substances that is the **enforceable** amount that must not be exceeded.
## Footnote
*enforceable*, not *harmful*. reflects the feasibility and cost of reaching 'good' levels
