Download 17 Human Population Size

All 18 First Semester Major Topic Summaries
To be used to study for the 2009-2010 APES Final
#1
Earth Science Concepts
Geological Time Scale
The geological time scale provides a system of chronologic measurement to time that is used by geologists, paleontologists and
other earth scientist to describe the timing and relationships between events that have occurred during the history of the Earth.
The Earth itself is about 4.57 billion years old. Different spans of time on the time scale are distinguished by their length and
major events during that time. We currently live in the Phanerozoic Eon, Cenozoic Era, Quaternary Period, Holocene Epoch, and
Atlantic Age.
Plate Tectonics, Earthquakes, Volcanism
Plate tectonic is the theory that postulates the movement of sections of the Earth’s crust, creating earthquakes, volcanic activity,
and the buildup of continental masses over long periods of time. The lithosphere, Earth’s crust, is broken up into what are called
tectonic plates. Tectonic plates are able to move because the Earth’s lithosphere has a higher strength and lower density than the
underlying asthenosphere. Some 14 major plates and a few minor ones make up the lithosphere. Subduction zones are found
where an oceanic plate slides under a continental plate. Collision zones are found where two continental plates converge, resulting
in uplifting into mountain ranges. Transform faults are boundaries where two plates are sliding past each other.
An earthquake is the result of a sudden release of energy in the Earth’s crust that creates seismic waves. At the Earth’s surface,
earthquakes manifest themselves by shaking and sometimes displacing the ground. When a large earthquake is centered offshore,
the seabed sometimes suffers sufficient displacement to cause a tsunami. The shaking in earthquakes can also trigger landslides
and occasionally volcanic activity.
A volcano is an opening in a planet’s surface or crust, which allows hot magna, ash, and gasses to escape from below the surface.
Volcanoes are generally found where tectonic plates are diverging or converging. Volcanoes can also form where there is
stretching or thinning of the Earth’s crust.
Seasons
A season is a division of the year, marked by changes in weather. Seasons result from the yearly revolution of the Earth around
the Sun and the tilt of the Earth’s axis relative to the plane of revolution. Seasons are usually marked by changes in the intensity
of sunlight that reaches the Earth’s surface, variations of which may cause animals to go into hibernation or to migrate, and plants
to be dormant. In some parts of the world, special “seasons” are loosely defined based upon important events such as a hurricane
season, tornado season or a wildfire season.
Solar Intensity
Solar intensity means how strong the sun hits the ground. Different bodies of the Solar System receive light of intensity inversely
proportional to the square of their distance from the Sun.
Latitude
Latitude gives the location of a place on Earth north or south of the equator. Lines of Latitude are the imaginary horizontal lines
shown running east-to-west (or west-to-east) on maps that run either north or south of the equator.
#2 Global Water Resources and Use
Freshwater: .024% of Earth’s water supplies are available as freshwater. The hydrologic cycle constantly
purifies and recycles water. Freshwater is an irreplaceable part of Earth’s natural capital, and is being
constantly degraded by human involvement. Irrigation is the biggest use of freshwater, followed by
industrial and domestic.
Saltwater: Largest saltwater stores are the Oceans of Earth. Saltwater is too expensive to desalinize for
human use and consumption.
Ocean Circulation: Warm ocean currents are corridors of warm water
moving tropics pole ward where they release energy to the air. Cold
ocean currents are corridors of cold water moving from higher latitudes
toward the equator.
Agricultural use: used for irrigation,
second
largest use of water in the US, up to 70
% of the
water taken from rivers and
groundwater goes into irrigation.
Water
for agriculture requires one hundred
times
more than we use for personal needs.
Industrial use: 15% of world wise water use is industrial; in 2000,
industries withdrew and estimate of 19,700 million gallons per day.
Industrial water use includes water used for fabricating, processing,
washing,
diluting, cooling, or transporting a product; incorporating water into a
product;
or for sanitation needs in the facility.
Domestic use: Used for every day human activities such as drinking, cooking, bathing, etc. Water is either
supplied by a city/county (public supplied) or acquired from personal wells.
Surface and Groundwater Issues: Over pumping of aquifers faster than aquifer can replenish erosion,
fertilizer and pesticides used in agriculture, and eutrophication cause pollution and other issues which
reduce availability and usability of surface and ground water.
Global Problems: The source of water pollution is humans; their activities in factories, homes, and waste
treatment centers cause toxic chemicals, which leak into groundwater stores.
Conservation: 1972 amendments to the Clean Water Act allowed for better regulation to reduce direct
pollutant discharges into waterways. The Water Quality Act of 1987 and the CWA form a basis of US
efforts to control pollution of US surface water.
Cadillac Desert: 1997 motion picture describing
William
Mulholland’s search for a new source of water to
supply
southern California. After discovering the Owens
River and
Owens River Valley, Mulholland drew up plans for
the first Los
Angeles aqueduct. Construction began in 1908, and
the aqueduct
was finally opened on November 5th, 1913. After its
opening, the
Los Angeles area grew dramatically, due to the
reliable water
supply.
#3 Soil and Soil Dynamics
Soil is complex, unconsolidated mixture of inorganic, organic, and living material that is found on the immediate surface of the
earth that supports plant life. Soil consists of dirt and sediments. One of the most important factors of a soil is its chemical
backbone from the parent rock. For example, limestone is basic and other rocks which comes from limestone has basic pH too.
Climate affects the making of the soil because before the parent rock can become part of the soil, it must be broken down
physically and chemically. Rain, for example, can take out elements and weaken the chemical bonds so that it may be broken
down easier into soil. Water and wind can also break down the rock. Time is also an important factor. Depending on the type of
rock, the act of breaking the rock down from rock to soil can take from a couple years to thousands and thousands of years.
Human activity also affects the soil.
Soil has many layers usually denoted by letters: O, A, B, C, and E. The O layer is usually comprised of organic materials from the
dead animals, dead leaves, and detritus. The A layer is organic materials mixed with inorganic materials, for example water. The
B level is where the minerals and clay are. Layer C contains the parent inorganic material for the soil.
Alfisols are a well-developed, highly fertile soil that forms in forests. These soils have undergone some leaching (water stripping
some chemicals from the soil as it percolates through it), leaving them with a subsurface layer of clay. This clay allows these soils
to remain moist, which helps to keep them fertile. They are usually found in temperate zones, which make them ideal for farming.
Aridisols, as the name implies, are soils that form in regions that are dry for long periods of the year. These soils have a high
calcium carbonate concentration, with layers of clay, silica, salt, and gypsum in the subsurface regions.
Mollisols are found in grassland areas and have a relatively rich, dark-colored surface zone as a result of the organic matter from
the being added from the grass. The fertile nature of these soils makes them excellent media for growing grain crops.
Oxisols are the heavily oxidized soils found in tropical and subtropical rainforest. These soils have undergone heavy amounts of
weathering and are very low in fertility outside of the very thin layer of organic material on the surface. Because water has
leached most of the other minerals out of the soil, oxisols are very high in concentrations of aluminum and iron and are mined
extensively in countries where rainforest are being chopped down.
Andisols are formed from the ash and ejecta from volcanoes. These soils are very high in glass grains and materials with pores.
This latter property means that these soils have a high ability to hold water.
Erosion is a gravity driven process that moves solid (sediment, soil, and other particles) in the natural environment or their source
and deposits them elsewhere. It usually occurs due to transport by wind, water, or ice; by down-slop creep of soil and other
material under the force of gravity; or by living organisms, such as burrowing animals, in the case of bioerosion.
Other soil problems are overuse, salinization, acidification, or other chemical soil contamination.
The main idea is that rocks are continually changing from one type to another and back again, as forces inside the earth bring
them closer to the surface (where they are weathered, eroded, and compacted) and forces on the earth sink them back down
(where they are heated, pressed, and melted). So the elements that make up rocks are never created or destroyed — instead, they
are constantly being recycled.
Soil conversation is a set of management strategies for prevention of soil being eroded from the earth’s surface or becoming
chemically altered by overuse, salinization, acidification, or other chemical soil contamination.
#4. Ecosystem Structure
Biological Populations and Communities
Population of different species. Living within an area and creates communities. An ecosystem is formed by the interaction of a community
of organism and their physical environment. Members of a population can be dispersed in 3 ways:

Clumped- some areas within the habitat are dense with organisms while others contain few members

Random – little interaction between members of the population. Leading to random pacing patters

Uniform – fairly uniform spacing between individuals.
Ecological Niches – particular area w/in habitat, occupied by an organism. Includes the function of that organism w/in that ecological community.
Specific adaptation acquired through evolution. To describe an organism niche involves a description of the organism’s adaptive trait habitat and
place in the food web.
Interactions among Species
They can benefit one or both species, harm one or both species, or not affect one of the species involved.

Amenalism (-) (O) – interaction between 2 species whereby one species suffers and the other species is not affected. Usually occurs
when one organism releases a chemical compound that is detrimental to another organism.

Commensalism (+) (O) - interaction between 2 species whereby one organism benefits and the other species is not affected. Forms of it
include phoresy-one using another for transportation, inquilism- use for housing, metabiosis-using something another created.

Competition (-) (-) - the driving force of evolution whether it is for competition for food, mating partners, or territory. Intraspecific
competition results in the organism that is best suited for change.

Mutualism (+) (+) – interaction between 2 species whereby both species benefit. Symbiosis- lifelong positive interaction that involves
close physical and/or biochemical contact such as the relationship between trees and mycorrhizal fungi.

Parasitism (+) (-) – interaction between 2 species whereby one species is benefited at the expense of another. Ectoparasite –lives on
host. Biotrophic parasites must keep their hosts alive (viruses). Necrotrophs- kill their hosts. Social parasites benefit parasites and
harms hosts.
Predation (+) (-) – hunt and kill prey.

Saprotrophism (+) (-) – obtain nutrients from dead or decaying plants or animals through absorption of soluble organic compounds
Keystone Species - a species that has a disproportionate effect on its environment relative to its biomass. Such species affect many other
organisms in an ecosystem and help to determine the types and numbers of various others species in a community. The organism is similar to the
keystone in an archway; while the keystone is under the least pressure of any of the stones in an arch, the arch still collapses without it. Similarly,
an ecosystem may experience a dramatic shift if a keystone species is removed, even though that species was a small part of the ecosystem by
measures of biomass or productivity.
A classic keystone species is a small predator that prevents a particular herbivorous species from eliminating dominant plant species.
Since the prey numbers are low, the keystone predator numbers can be even lower and still be effective. Yet without the predators, the herbivorous
prey would explode in numbers, wipe out the dominant plants, and dramatically alter the character of the ecosystem.
They can be predators, mutualists, or ecosystem engineers- any organism that creates or modifies habitats
Examples: sea stars, sea otters in kelp forests, jaguars in central and south America, grizzly bears in North America, prairie dogs
Species Diversity - organisms that live in different environments are specifically adapted to their particular biome
Ex: Aquatic, desert, grassland, forest, temperate scrub forest land, tundra organisms.
Edge Effects - how local environment changes along some type of boundary or edge.
Forest edges created when trees are harvested, especially when clear-cut (tree canopies provide shade and retain moisture so young
trees can grow. Sunlight makes the land warmer and drier.)
Edge effect is result of two different conditions influencing plants and animals that live on the edge. Edge species are species that can
adapt to both environments.
Major Terrestrial and Aquatic Biomes

Deserts – 15 and 25⁰ N and S latitude. Generally in the interior of continents. Takes up about 20% land mass. Rainfall <20 in. little
nutrients, not abundant in organic matter. Little hummus in the soil profile.

Tropical Rainforests – high, constant temperature (27 C) rainfall- 75-100 km/yr. high species diversity. Dense vegetation. Soil low in
nutrients, mostly stored in vegetation. Decomposition of organic material very fast due to temperature and moisture. Leaching is high.
Humans are clearing it for agriculture and cattle raising, using technique called slash and burn.

Temperate Deciduous Forests – rapid decomp due to mild temp and precipitation. Results in small amount of litter on the surface. Soil
generally poor in nutrients. Mild climate, diverse understory with tall deciduous trees. Low density of small animals. Shade prevents much
ground vegetation.

Chaparral (temperate shrubland) - avg rainfall: 30-40 in/yr/ dense shrub growth. Slow decomp during dry months. Few large mammals.
Hot dry summer, mild cool rainy winter.

Grassland – too dry for forests, too wet for deserts. Seasonal rainfall. Moderate temp. Occupies approx. 25% of land area. Few trees
and shrubs due to fire and water availability. Soil rich in organic matter. Upper soil horizon rich in hummus.

Savannas – warm year round. Scattered with trees/ dry followed by rainy seasons. Grassland with deciduous shrubs and trees. Food
limited in dry season. Soil rich in nutrients. Resource for predators- a lot of bird and grazing animals.

Tundra - 60⁰ N latitude and above. Alpine tundra located in mountainous areas. Above tree line with well drained soil. Small rodents and
insects. Arctic tundra- frozen, treeless plain. Low rainfall and avg temp. Poor drainage. Low vegetation, soil has few nutrients, little
decomp.

Temperate boreal forest – taiga. 45-60⁰ N latitude. 17% land surface. Cold climate. High latitude/altitude. Poor soil. A lot of leaching.
Acidic soil. Low temp. Slow decomp. Small trees. Little light in understory. Low biodiversity. Fire, storm, insect infestation.
Ecosystem Type
Tropical Rain Forest
Estuary
Swamps and Marshes
Savanna
Temperate Grassland
Deciduous Temperate Forest
Boreal Forest
Polar Tundra
Desert
Productivity of Biomes
Net Primary Productivity(Kilocalories / square meter / year)
9000
9000
9000
3000
2000
6000
3500
600
< 200
Approx.Kilocalories/square meter/ day
25
25
25
8
6
16
10
2
1
#5 Energy Flow: Photosynthesis and Cellular Respiration; Food Webs and Trophic Levels;
Ecological Pyramids; 10% Energy Transfer
Photosynthesis: chemical process in plants converting light energy to chemical energy and storing it as
sugar bonds
6CO2 + 6H20 (+ light energy) → C6H12O6 + 6 O2
Cellular Respiration: to release the energy required for the work done by that cell; purpose is to release the
potential energy contained in organic molecules to perform the activities of the organism
C6H12O6 + 6 O2 → 6CO2 + 6H20 (+ light energy)
Food Webs:
Energy
Flowthe interconnection of food chains




As you move up the food chain, there is less energy
available.
Most of the energy obtained is used as heat.
Heat is the lowest form of energy.
Pyramids
Once the energy is used Biomass
as heat, it will
never be recycled.
Courtesy of Marietta College
Trophic levels: feeding
Diagram showing the
biomass at each
levels in a food chain
trophic level of a food
• As you move up the food chain, there is less energy available.
chain
 Primary producers → consumers (herbivore) → consumers
Courtesy of
• Most of the energy obtained is used as heat.
University of
(carnivore) → decomposers
Winnipeg
• Heat is the lowest form of energy.
10% Energy Transfer and the Ecological Pyramid
• Once the energy is used as heat, it will never be recycled.
 The sun loses 90% of its energy as heat and the other 10%
goes to the producers
The sun’s energy is absorbed by the producers, where 10%
 The sun’s energy is absorbed by the producers, where 10% of the energy
isispassed
tothethe
primary
the energy
passed to
primary
consumer. As you mov
up the pyramid, the consumer will only gain 10% of the
consumer. As you move up the pyramid, the consumer will only gain
10%
of
the
energy
from
its
energy from its prey.
prey.
Therefore, you obtain more energy by eating lower on the
biomass pyramid
 More energy is obtained when eating lower on the ecological pyramid.
• The sun loses 90% of its energy as heat and the other 10%
goes to the producers.
#6 Ecosystem Diversity
Diversity is the variety of different plant or animal species in a habitat or ecosystem. The number of species of plants,
animals, and microorganisms are the diversity of genes in these species. The different ecosystems on the planet, such
as deserts, rainforests and coral reefs are all part of a diversity system. Biodiversity is important because it boosts
ecosystem productivity. For example, a larger number of plant species means a greater variety of crops; greater
species diversity ensures natural sustainability for all life forms; and healthy ecosystems can better withstand and
recover from a variety of disasters. We still need to preserve the diversity in wildlife.
Natural selection evolves the evolution of a species that is best adapted to survive the environment. It’s the traits that
a species passes on to its offspring so that it can survive it its habitat. Over generations a species evolves and becomes
more efficient then it once was. It is survival of the fittest and the so-called weak tend to die out. With the feeding
habits of the 13 finches on the Galapagos Islands, Darwin studied their beaks and later found this could help them
survive by finding food.
Evolution refers to change over time, or transformation over time. Evolution requires that all natural forms arose from
their ancestors and adapted over time to their environments, thus leading to variation. In evolution, there are many
rules for the survival of a species. There are also numerous ways in which evolution occurs, the most noted are
Natural Selection and Adaptation.
difficult to duplicate. Over 100,000 different animal species — including bats, bees, flies, moths, beetles, birds, and
granted such as clean water, timber, and habitat for fisheries, and pollination of native and agricultural
plants. Natural ecosystems and the plants and animals within them provide humans with services that
would be very difficult to duplicate. Over 100,000 different animal species — including bats, bees, flies,
moths, beetles, birds, and butterflies — provide free pollination services for example. One third of human
food comes from plants pollinated by wild pollinators. Unfortunately, we take advantage of our ecosystem
services. Many human activities disrupt ecosystems every day including:








Runoff of pesticides, fertilizers, and animal wastes
Pollution of land, water, and air resources
Introduction of non-native species
Over-harvesting of fisheries
Destruction of wetlands
Erosion of soils
Deforestation
Urban sprawl
The choices we make today in how we use land and water
resources will have enormous consequences on the future sustainability of earth’s ecosystems and the
services they provide.
#7: Natural Ecosystem Change-Climate shifts, species movement, ecological succession
Whaaaaat? Climate Change, what are you talking about? Over
the last few decades scientists have observed that there has been a slow but
steady rise in the Earth’s average temperature. This is mostly caused by the
increase in anthropogenic greenhouse gas concentrations. The three
major gases are: carbon dioxide, methane, and nitrous oxide. These gases
absorb the heat radiating from the Earth and trap it so that it heats the lower
atmosphere. The increase in the Earth’s temperature will lead to changes such as lessening of ice sheets
and glaciers, lost of biodiversity, continued rising average of ocean levels, frequency in duration of storms,
increase in number of hot days, and countless other issues.
Adaptations to the warmer climate will need to occur at many
levels of society. Technological improvements like carbon
sequestration and the reduction of emissions from engines,
behavioral changes such as turning off lights to conserve
electricity, and policy changes such as enacting new likes and
legislation will all be necessary in the next few decades.
Where art thou, species?!
As the world’s climate changes, many species are being forced out of
their habitats. While some species are able to migrate to a cooler territory, those in the tropics have no
where else to go ): The key dangers of moving small numbers of organisms to a new location for purposes
of reintroduction are inbreeding, hybridization or interbreeding with local species, and failure of survival.
They newly established population may carve its own evolutionary path and form a new species or
subspecies.
Ecowhat?! Succession who?! Ecological succession is when species of plants/animals are continually coming and
going; evolving and dying out. If ecological succession begins in a virtually lifeless area, such as the area bellowing a
retreating glacier, it is called primary succession. Secondary succession is ecological succession that takes place
where an existing community has been cleared (by events
such as fire, tornado, or human impact), but the soil has been
left intact. The organisms in the first stages of either type of
succession are referred to as pioneer species. The final stage
of succession, in which there is a dynamic balance between
the abiotic and biotic components of the community, is
referred to as the climax community. An example of
ecological succession is:
#8
Natural Biogeochemical Cycles
Carbon Cycle: Carbon moves around when things eat each other,
geological sedimentation of carbon in ocean and when fossil fuels are
burned.
CO2 in the air
web
Photosynthesis
Enters plant
Consumed
Enters food
Goes
to
soil
Becomes detritus, eaten by detritus feeders/ decomposers
Phytoplankton remove CO2 from
inorganic carbonates in sea water
Consumed
Enter marine food web
Respiration
By decomposers
Phosphorous Cycle: The shortage of phosphorous in an ecosystem can be a limiting factor and an excess
can cause unwanted algal growth. Phosphate (PO43-) is found in rock and soil minerals. As it breaks down,
the ions are released and absorbed by plants from the soil. It then is consumed by a primary consumer, and
continues through the food chain. It is then released by cell respiration or is decomposed and is released in
the waste material.
Sulfur Cycle: Within the terrestrial portion, the cycle begins with the weathering of rocks, releasing the
stored sulfur and comes into contact with air where it is converted into sulfate (SO4). The sulfate is taken up
by plants and microorganisms and is converted into organic forms; animals then consume these organic
forms through foods they eat, thereby moving the sulfur through the food chain. As organisms die and
decompose, some of the sulfur is again released as a sulfate and some enters the tissues of microorganisms.
Nitrogen Cycle: Nitrogen Gas (N2) is converted to ammonia (NH3) which is then converted to NO3 (by
nitrogen fixation- lightening) or NH4 by rhizobium, the bacteria in
legumes, which provide nutrients for plants. The plants are then eaten
by animals, which die, resulting in ammonification.
The aquatic ecosystems acquire nitrogen in the form of NH3 or NH4 by
eutrophication. Aquatic plants are then eaten by animals, which then
reenter cycle.
Water Cycle: Water rises into the atmosphere through evaporation or
transpiration (through plants) and returns through condensation and
precipitation. Hadley cells and rain shadows affect precipitation. The
Hadley cell affects precipitation because on one side, dry air absorbs
moisture, and when it ascends it releases the moisture. The rain shadow affects precipitation because the
warm, moist air dries by the time it reaches the top of the mountain. The leeward side of the mountain is
dry. Assimilation is the ability of water to purify itself.
Conservation of Matter: The first law of thermodynamics: Energy is neither created nor destroyed.
The second law of thermodynamics: In an energy conversion, some of the usable energy is always lost (i.e.
in the form of heat)
#9 Agriculture, Feeding a Growing Population
Human nutritional requirements
 The human diet must provide the following:
 Calories: enough to meet our daily energy needs
 Amino Acids: There are 9 “essential” amino acids
that we need for protein synthesis
 Fatty Acids: There are 3 “essential” fatty acids that
we cannot synthesize from other precursors
 Minerals, inorganic ions: We need 18 different ones; a few like calcium in relatively
large amounts; most, like zinc, in “trace” amounts
 Vitamins: 12 small organic molecules that we cannot synthesize from other
precursors in our diet
Types of agriculture
 Conventional Agriculture: is mono-cropping (planting only one crop year-round). Monocropping eliminates diversity. This type of agriculture is based on maximizing the output of
a narrow range of species.

Sustainable Agriculture: integrates three main goals: environmental stewardship, farm
profitability, and prosperous farming communities.
Green Revolution – a significant increase in agricultural productivity resulting from the introduction of
high-yield varieties of grains, the use of pesticides, and improved management techniques.
Genetic engineering and crop production
 Crop production is the amount of crops produced in a year and is a complex business,
requiring many skills and covering a variety of operations throughout the year.
 Genetic engineering refers to manipulating genes in a way that does not occur naturally.
The organism’s genes are manipulated indirectly. It also alters the structure and
characteristics of genes directly.
Deforestation – is the clearance of naturally occurring forests by the
humans' logging and/or burning of trees in a forested area.
processes of
Irrigation – is an artificial application of water to the soil. It is usually used to assist the
growing of crops in dry areas and during periods of inadequate rainfall. Repeated
irrigation can cause serious problem, including a significant buildup of salts on the soil’s
surface that make the land unusable for crops.
Sustainable agriculture – agriculture that maintains the integrity of soil and water resources such that it
can be continued indefinitely.
Sustainable yield – the amount of food required to sustain a population.
 Developed nations would have high amounts of crop, which leads to crop surpluses.
#10 Agriculture, Controlling Pests
Types of Pesticides (mostly a Second Semester Topic-according to Dr. Griffith)
 Biodegradable- means that it can be broken down in soil in a feasible amount of time
 Non biodegradable- means that the pesticide cannot be broken down in an amount of time that makes is
useful (example- DDT)
 DDT- was originally used as a pesticide for plants, but was being consumed by animals. When these
animals were eaten by predators, the DDT made its way up the food chain (bioaccumulation). A written
source is Silent Spring by Rachel Carson. DDT is non biodegradable, hydrophobic and lipophilic. The
means it cannot be broken down naturally, dissolved in water, and it lives in the fats of animals
Cost of Pesticide Use
 The more pesticides are used, the more likely the pests are to become resistant to them. Since the pests
become immune to the pesticides people, the farmers think that they need to use more pesticides. This
costs more money and does not get rid of the pests
 Have effects on human. (Remember movie where the little boy had cancer)
 Pesticides do not add humus to the soil. Humus is what provides the soil with the nutrients that it needs.
It is also spongy, so it helps prevent erosion. Since it does not add humus, it reduces the soil’s water and
nutrient holding
capacity. This makes the soil
more susceptible to
erosion.
Benefits of Pesticide Use
 Inorganic chemical
bought, transported,
 Because of this, they
farmers, and excellent
 They
are
also
makes them attractive
fertilizers are easily found,
stored, and used.
are very convenient for
and getting rid of pests.
relatively
cheap,
which
to farmers
Integrated Pest Management
 A program consisting of two or more methods of pest control carefully integrated together and designed
to avoid economic loss from pests
 It’s goal is to minimize the use of environmentally hazardous synthetic chemicals
 One type of IPM is crop rotation, which means growing crops in the same patch of land that are infected
by different pests. This doesn’t allow the pests to settle and reproduce
#11
Major Semester 1 Topic: Rangelands
What are rangelands? Expansive grasslands with native vegetation. Examples of rangeland biomes: savannas,
deserts, tundras.
Why are rangelands important? Most of our food comes from animals that are farmed, like cows, which are grazed
on grasslands.
*Important concepts: deforestation, federal rangelands, wilderness
Deforestation: Forest is removed and the land is used for other purposes, like grazing. The forest is not allowed to
regrow.
Reasons for deforestation: conversion into pastures and agricultural land
Consequences of deforestation: productivity is reduced, nutrients reduced, biodiversity is diminished, soil
becomes prone to erosion, change in the water cycle, a major carbon dioxide sink is lost (forests remove CO2 from
the air), the land no longer yields forest products, people lose their livelihoods.
Types of forest management:
 Rotation: monitoring a stand of trees from growth to harvest
 Even-aged management: trees of a uniform age are managed until harvest, cut down, and
replanted. This continues the cycle in a dependable sequence
 Clear-cutting: removing an entire stand at a time. This severely decreases biodiversity and
affects adjacent ecosystems.
 Uneven-aged management:
o Selective cutting: some mature trees are removed in small groups, leaving behind a
forest that continues to function
o Shelter-wood cutting: cutting the mature trees in groups over a specific period (i.e.
10 years) which allows time for the trees to reproduce, provide seeds, and give
shelter to growing seedlings
Federal Rangelands: a commons (remember tragedy of the commons!) that is owned by the federal government
(i.e. a national park or national forest). Federal rangelands are important because they protect important
ecosystems, raise awareness about endangered species, and allow people to enjoy the beauty of natural lands.
Wilderness: federal land that is designated off-limits to development of any kind but is open to public recreation,
such as hiking, nature study, and other activities that have minimal impact on the land.
*Other concepts: overgrazing, desertification, rangeland management
Overgrazing: contributes to erosion, soil degradation, and a loss of nutrients.
Desertification: A loss of more than 10% productivity due to erosion, soil compaction, forest removal, overgrazing,
drought, salinization, climate change, and depletion of water sources. Makes the land more desert-like.
Rangeland Management: managing the natural resources on the rangeland
CLEAR-CUTTING IS BAD. 
FEDERAL PROTECTION IS GOOD. 
#12 Energy Concepts
1st law of thermodynamics-energy is neither created nor destroyed but may be converted to one form or
another (example: photosynthesis-energy from sun converted to chemical energy in the bonds that hold
together atoms in carbohydrates)
2nd law of thermodynamics- when energy is changed from one form to another some useful energy is always
degraded into lower quality energy (usually heat),
(Example: food chain and 10% rule)
 entropy (disorder) of the universe is increasing
Units of Energy
 Energy units: Joule (J), Calorie (cal)
 Power Units Watt (W), Horsepower (hp)
Conversions: We will do this next semester according to Dr. Griffith
Renewable Energy
Solar, Wind, and hydroelectric energy are renewable because their supplies are not deleted by human use
Hydroelectric energy-generated by the force of water, electricity is created when water turns a turbine.
 Release no pollutants, only thermal pollutant
 Must dam rivers, may disrupt fish in water sources
Solar energy-active collection using solar panels
Wind energy-wind turns turbine creating energy
Nonrenewable
Coal, oil, natural gas because they have a limited amount available
#13 Water Pollution
Types of water pollution include: contaminants from sewage plants, industrial waste, pesticides and fertilizers from agricultural
run-off. Four categories of water pollution: toxic pollution, nutrient pollution, sediment pollution, and bacterial pollution
Main Causes: -Manufacturing plants use the water to carry away waste that can contain phosphates, nitrates, lead, mercury and
other harmful and toxic substances.
-Ground water pollution occurs when harmful elements, such as oil, debris, chemicals and other contaminants get washed up by
rainwater and then seep back into underground water supplies called ground water.
Effects: -Thermal Pollution: Hot water discharge from factories can change the temperature and chemistry of the water
-Toxins in the water are lethal: Blood diseases, heart disease and nervous system disorders are commonly linked to the effects of
water pollution
-Dissolved Oxygen level is lowered due to the increase in BOD and therefore fish and other life may die because of lack of
oxygen.
Cultural Eutrophication: Process which speeds up natural eutrophication because of human activity. Due to clearing of land and
building of towns and cities, runoff water is accelerated and more nutrients such as phosphates and nitrate are supplied to the
lakes and ponds..These nutrients result in an excessive growth of plant life known as an algal bloom. This not only changes the
lake's natural food web, but also reduces the amount of dissolved oxygen in the water for organisms to breathe.
Water Purification: -Filtration and sedimentation, biological processes such as slow sand filters or activated sludge, chemical
process such as flocculation and chlorination and the use of electromagnetic radiation such as ultraviolet light are all ways to
purify water.
Sewage Treatment: Sewage can be treated close to where it is created (in septic tanks, biofilters or aerobic treatment systems), or
collected and transported via a network of pipes and pump stations to a municipal treatment plant (see sewerage and pipes and
infrastructure).
Solution: -Clean Water Act in 1972 puts limitations on the types and amounts of material that can be discharged into our bodies
of water, and also sets quotas on the amounts of pollutants that can be in water before it becomes unsafe for use by humans and
wildlife.
-On a smaller scale we can help by becoming educated on how to avoid pollution. This can include the proper disposal of
household chemicals so they don’t make their way untreated into bodies of water or water supplies and making sure your car isn’t
leaking fluids that can get mixed in with runoff when it rains and cause ground water pollution.
# 14: Loss of Biodiversity:
Endangered and Extinct Species:
-Main Causes: Habitat loss due to overuse or pollution of natural habitats.
 Building homes in natural habitats (clear cutting of forests for farm/graze land)
 Overuse of natural resources for economic benefits (ecosystem capital)
 Pollution of natural habitats(smog, chemical runoff into water, climate change)
 Introduction of invasive species threaten the native organisms and the local
biodiversity
Some Species that are Endangered or Extinct:
 Black-Footed Ferret: Prairie Dogs in Wyoming were killed b/c they were threatening
crops. However, this also hurt the Ferret population. They were thought to be extinct,
but in 1987 18 were found, captured, and bred. The Captive Breeding Program brings
their number to over 1000.
 Whooping Crane: Eggs raised by sandhill cranes in recovery effort
 Red Wolf: Only 17 remained in North Carolina before a restoration program started.
Wolves are released onto some private property.
 Peregrine Falcon: Numbers affected by DDT spraying—bioaccumulation
 Spotted Owl: Habitat loss due to clear-cutting of forests
Relevant Laws and Treaties:



Lacey Act of 1900: Prohibits interstate commerce in illegally killed wildlife.
1973 Endangered Species Act: Protection of endangered/threatened species AND their
habitats
CITES: An international treating somewhat protecting endangered and threatened species by
restricting trade in the species or products
Why should we even prevent the loss of biodiversity?
 Intrinsic, aesthetic values.
 Economic values of ecosystem capital from natural habitats(trees for wood, fish for food, etc)
When biodiversity is lost, then ecosystem capital also decreases.
 Possibility of some species that have medicinal properties such as the Pacific Yew tree that
produces the anti-tumor drug Taxol.
#15 Population Biology Concepts
Reproductive Strategies
Depending on the type of animal, many different reproductive strategies can be used. An animal that uses
the R-strategy reproduces many small offspring at an early age. Often times, these offspring go unprotected,
and the mother does not care for them. Since they are unprotected, many must be produced to ensure that a
substantial amount will survive to reproduction age and restart the cycle. An animal that follows the Kstrategy waits until later to reproduce and only gives a few offspring. In turn, however, this animal cares for
its small amount of offspring to ensure that they survive to reproductive age. Animals that produce less
offspring will often produce less often, and animals that produce many will mate many times in their
lifetime. An example of an R-strategist is a frog. An example of K-strategist is a human.
Carrying Capacity
The carrying capacity of a population is the limit of of the population size that can live sustainably, or
without degrading effects in the long term. Carrying capacity can be improved with advances in technology
but often times, carrying capacity is lowered due to environmental pressures. As an area's ability to support
life diminishes, so does the carrying capacity. If the population greatly exceeds the carrying capacity, the
population will experience a J-curve that will end in an inevitable crash and in some circumstances,
extinction of a population.
Population Curves
There are two types of population curves, a J-curve and the S-curve. These two curves are the general
trends that populations follow.
J-Curve
characterized by a quick, exponential increase in population followed
even quicker crash. J-curves occur under optimal conditions when
predato has become extinct of prey has become plentiful. After the
a population may restart the trend again which happens most often
Otherwise the population may become extinct.
A J-curve is
a sharp and
either a
J-curve crash,
with pests.
S-curve
An S-curve is characterized by a gradual increase followed by
small oscillations about the carrying capacity. When this
occurs, the population is said to be in equilibrium and this is
caused because of environmental resistance. These
populations can live sustainably for many years.
Critical Number
The critical number is the level at which if a population descends below, the population may not be able to
recover and would eventually go extinct. Sometimes the critical number may be more than the number in a
certain flock, indicating interaction between groups is necessary for survival.
#16: Human Population Dynamics
Historical Population Sizes

Until the 1800’s, after the industrial revolution, human
population has remained pretty consistent. However,
since then, because of technology, medicine, and
agriculture, the human population has increased
exponentially, currently at about 6.8 billion and ever
increasing.
Courtesy of: http://www.flame.org/~cdoswell/Earth_Abides/population_curve.gif
Distribution



Of these 6.8 billion people, the large
majority is distributed in a few countries, and
in developing countries as opposed to
developed.
China and India each contain about 1/5 of the
world’s population
Developing countries’ age-structure
diagrams (pictured and explained below) are
usually shaped like the first one because they
have so many kids!
Fertility Rates

Families in developing countries
have more kids and faster
growing populations because of a
lack of…
o Family planning
o Access to contraceptives
o Infant survival (many
young kids die from
disease, etc.)

Age-structure
diagrams

Growth rate-how fast
a country’s population
grows based on birth
rate-death rate
 (B.R.-D.R.)/10=% rate
of growth
 Doubling times70/ percent rate of
growth
Population pyramids for 4 stages of the demographic transition model
Courtesy of: http://en.wikipedia.org/wiki/File:Dtm_pyramids.png
Demographic transition
Courtesy of: http://www.eoearth.org/upload/thumb/0/04/Figure_4_Classic_Stage
s_of_Demographic_Transition.gif/300px-Figure_4_Classic_Stages_of_Demographic_Transition.gif
Stage 1: Primitive stability, high crude death rate and crude birth rate
Stage 2: Declining crude death rate
Stage 3: Declining crude birth rate
Stage 4: Modern stability, low crude death rate and low crude birth rate
#17 Human Population Size
~ 6,796,029,975
or
6.8 Billion
from http://www.census.gov/main/www/popclock.html
Strategies for sustainability:
Promoting development of countries:
Efforts to reduce population size by helping countries undergo demographic transition
to reach “modern stability.”
Ways to reduce population:
 Increase availability of birth control
 Reduce infant mortality
 Increase education
 Raise status of women
 Eradicate poverty
Millennium Project:
Set up millennium development goals (MDGs) for solving population problems in the
new millennium. Many groups, including the U.N. Agency and many NGOs and
government agencies are working achieving the goals.
World Bank:
Agency under the U.N. that provides loans to low-income developing countries. Good
and bad. Focused on development, not environmentalism. May also increase
countries’ debt.
Case Study:
Kerala
Southwestern province in India. Low fertility rate of 1.8 (below replacement level).
Lower infant mortality rate and higher life expectancy than rest of India. Stable
population because of public policy commitment to health care and
education.
National Policies:
China’s One Child Policy was enacted in the 1970’s to limit China’s population growth.
It is very controversial for its creation of a gender gap in China and many other
reasons.
#18 Impacts of Human Population Growth
Hunger: the most commonly used term to describe the social condition of
people who frequently experience, or live with the threat of experiencing,
the physical sensation of hunger
Malnutrition: is a general term for a condition caused by improper diet or
nutrition
Famine: a widespread scarcity of food that may apply to any faunal
species, which phenomenon is usually accompanied by regional
malnutrition, starvation, epidemic, and increased mortality
Starvation: a "state of exhaustion of the body caused by lack of food." This state may precede death
Disease: a disordered or incorrectly functioning organ, part, structure, or system of the body resulting from
the effect of genetic or developmental errors, infection, poisons, nutritional deficiency or imbalance,
toxicity, or unfavorable environmental factors; illness; sickness; ailment.
For example, in Kenya AIDS is the leading cause of death and because of the lack of funds they are unable
to get necessary medical help.
Habitat Destruction: As human population grows,
organism’s habitats are displaced or destroyed, reducing
biodiversity. Other organisms that occupied the habitat have
the carrying capacity so that populations decline and
becomes more likely.
For example, mining, logging, trawling, or urban sprawl are
contribute to habitat destruction.
reduced
extinction
all
Economic Effects:
Population growth has very powerful effects on the economy. It is estimated that approximately one acre of
land is lost due to expansion and urbanization for every person born in the United States. The more people
there are, the lower the standard of living. There is not enough home grown food in the country so food,
medicine and supplies have to be imported from other countries, which costs more and affects the economy.
The United States is the world’s largest food exporter, and if a higher percentage of our food had to go
towards our citizens, then there is a question of the future survival of millions around the world depending
on our exports.
Resource Use:
A necessary result of increasing population is expansion and urbanization. Unfortunately the land is also
affected by these things, including the loss of cropland due to erosion, water logging and salinization. The
growing human population also has a significant detrimental intake of our world’s fresh water. The water
used in agriculture is being depleted in America at 130% of its recharge rate, proving our lack in making our
water resources sustainable in comparison to our population. At the current rate of our usage, even with vast
improvement in sustainability, in the next 30 to 50 years, there will be no fossil fuels left on this planet due
to human overpopulation.