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Lesson #1. Chapter 11 Biodiversity and Conservation Biology Essentials. Characterize the scope of biodiversity on Earth. • Biodiversity can be thought of at three levels commonly called species diversity, genetic diversity, and ecosystem diversity.

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chapter 11 biodiversity and conservation biology essentials
Chapter 11 Biodiversity and Conservation Biology Essentials

Characterize the scope of biodiversity on Earth.

• Biodiversity can be thought of at three levels commonly called species diversity, genetic diversity, and ecosystem diversity.

• Roughly 1.7 – 2.0 million species have been described so far, but scientist agree that the world holds millions more.

  • Some taxonomic groups (such as insects) hold far more diversity than others.
  • Global estimates of biodiversity may be based on extrapolations from local areas and certain taxonomic groups.
chapter 11 biodiversity and conservation biology essentials1
Chapter 11 Biodiversity and Conservation Biology Essentials

Characterize the scope of biodiversity on Earth. (con’t)

  • Diversity is unevenly spread across different habitats, biomes, and regions of the world.
chapter 11 biodiversity and conservation biology essentials2
Chapter 11 Biodiversity and Conservation Biology Essentials

Contrast background extinction rates with periods of mass extinctions.

  • Species have gone extinct at a background rate of roughly one species per 1 – 10 million species per year. Most species that have ever lived are now extinct.
  • Earth has experienced five mass extinction events in the past 440 million years.
  • Human impact is presently initiating a sixth mass extinction.
chapter 11 biodiversity and conservation biology essentials3
Chapter 11 Biodiversity and Conservation Biology Essentials

Evaluate the primary causes of biodiversity loss.

  • Habitat alteration is the main cause of current biodiversity loss.
  • Invasive species, pollution, and overharvesting are also important causes.
  • Climate change threatens to become a major cause soon.
chapter 11 biodiversity and conservation biology essentials4
Chapter 11 Biodiversity and Conservation Biology Essentials

Specify the benefits of biodiversity.

  • Biodiversity is vital for functioning ecosystems and the services they provide us.
  • Wild species are sources of food, medicine, and economic development
chapter 11 biodiversity and conservation biology essentials6
Chapter 11 Biodiversity and Conservation Biology Essentials

Assess the science and practice of conservation biology.

  • Conservation biology studies biodiversity loss and seeks ways to protect and restore biodiversity.
  • Conservation biologists integrate research at the genetic, population, species, ecosystem, and landscape levels.
  • Island biogeography theory explains how size and distance influence species richness on islands. It also applies to terrestrial islands of habitat in fragmented landscapes.
chapter 11 biodiversity and conservation biology essentials7
Chapter 11 Biodiversity and Conservation Biology Essentials
  • … It also applies to terrestrial islands of habitat in fragmented landscapes.
chapter 11 biodiversity and conservation biology essentials8
Chapter 11 Biodiversity and Conservation Biology Essentials

Compare and contrast traditional and innovative biodiversity conservation efforts.

  • Most conservation efforts and laws so far have focused on threatened and endangered species. The U.S. Endangered Species Act has been effective by controversial.
  • Single-species recovery efforts include captive breeding and reintroduction programs.
  • Charismatic and well-known species are often used as tools to conserve habitats and ecosystems. Increasingly, landscape-level conservation is being used.
  • International conservation approaches include treaties, biodiversity hotspots, community-based conservation, debt-for-nature swaps, and conservation concessions.
lesson 2
Lesson #2

Lab: Food for Thought… Tropic Levels

Energy pyramids, otherwise known as trophic level diagrams, are used to represent the flow of energy through an ecosystem. This lab provides information on food chains, energy pyramids and let you do some problem solving. As you do these, you will think about the benefits and drawbacks of eating at lower trophic levels.

define the terms industrialized agriculture and monoculture
Define the terms industrialized agriculture and monoculture.

Industrialized Agriculture

A form of agriculture that is more centralized and uses technology such as mechanized groundwater irrigation systems and production of fertilizers in order to grow crops.


The planting of large areas with a single species or even a single strain or subspecies in farming.

this lecture will help you understand
This lecture will help you understand:
  • The relationship between soils and agriculture
  • Major agricultural developments
  • The fundamentals of soil science
  • Causes and consequences of soil erosion and degradation
  • Principles of soil conservation
no till agriculture in southern brazil
No-till agriculture in Southern Brazil
  • Southern Brazil’s climate and soils make for bountiful harvests
  • Repeated planting has diminished the productivity of the soil
  • Leaving crop residues on their fields after harvesting and planting “cover crops” reduced erosion, increased yields and cut costs
  • These no-till techniques have benefited everyone
soil successful agriculture requires healthy soil
Soil: Successful agriculture requires healthy soil.
  • Land devoted to agriculture covers 38% of Earth’s land surface
  • Agriculture = practice of raising crops and livestock for human use and consumption
  • Cropland = land used to raise plants for human use
  • Rangeland or pasture = land used for grazing livestock
  • Soil = a complex plant-supporting system consisting of disintegrated rock, organic matter, water, gases, nutrients, and microorganism
    • It is a renewable resource
population and consumption degrades soil
Population and consumption degrades soil
  • Feeding the world’s rising human population requires changing our diet or increasing agricultural production
  • Land suitable for farming is running out
  • We must find ways to improve the efficiency of food production
  • Mismanaged agriculture turns grasslands into deserts; removes forests; diminishes biodiversity; and pollutes soil, air, and water
    • Fertile soil is blown and washed away
millions of acres of cropland are lost each year
Millions of acres of cropland are lost each year

We lose 5-7 million ha (12-17 million acres) of productive cropland annually

soil degradation has many causes
Soil degradation has many causes
  • Soil degradation results from deforestation, agriculture and overgrazing
  • Over the past 50 years, soil degradation has reduced global grain production by 13%
agriculture arose 10 000 years ago as people began breeding crops and domesticating animals
Agriculture arose 10,000 years ago as people began breeding crops and domesticating animals.
  • Agriculture was invented independently by different cultures
  • The earliest plant and animal domestication is from the “Fertile Crescent” of the Middle East
    • Wheat, barley, rye, peas, lentils, onions, goats, sheep
traditional agriculture
Traditional agriculture
  • Traditional agriculture = biologically powered agriculture, using human and animal muscle power
    • Subsistence agriculture = families produce only enough food for themselves
    • Intensive agriculture = produces excess food to sell
    • Uses animals, irrigation and fertilizer, but not fossil fuels
industrialized agriculture is a recent phenomenon
Industrialized agriculture is a recent phenomenon
  • Industrialized agriculture = using large-scale mechanization and fossil fuels to boost yields
    • Also uses pesticides, irrigation and fertilizers
    • Monocultures = uniform planting of a single crop
  • Green revolution = the use of new technology, crop varieties and farming practices introduced to developing countries
    • Increased yields
    • Created new problems and worsened old ones
define the terms desertification and salinization
Define the terms desertification and salinization.


The process of creating a desert where there was not one before. Farming in marginal grasslands, which destroys the soil and prevents the future recovery of natural vegetation, is an example of desertification.


The buildup of salts in surface soil layers.

soil as a system includes diverse biotic communities that decompose organic matter
Soil as a system… includes diverse biotic communities that decompose organic matter.
  • Soil consists of mineral matter, organic matter, air, and water
    • Dead and living microorganisms, and decaying material
    • Bacteria, algae, earthworms, insects, mammals, amphibians, and reptiles

Since soil is composed of living and non-living matter, it is considered an ecosystem

soil formation is slow and complex influenced by climate organisms relief parent material and time
Soil formation is slow and complex… influenced by climate, organisms, relief, parent material, and time.
  • Parent material = the base geologic material of soil
    • Lava, volcanic ash, rock, dunes
    • Bedrock = the continuous mass of solid rock comprising the Earth’s crust
  • Weathering = the physical, chemical, or biological processes that break down rocks to form soil
    • Physical (mechanical) = wind and rain, no chemical changes in the parent material
    • Chemical = substances chemically interact with parent material
    • Biological = organisms break down parent material
other processes affect soil formation
Other processes affect soil formation
  • Erosion = the dislodging and movement of soil by wind or water
    • Occurs when vegetation is absent
  • Biological activity includes deposition, decomposition, and accumulation of organic matter
    • Humus = a dark, spongy, crumbly mass of material formed by partial decomposition
a soil profile consists of distinct horizons with characteristic properties
A soil profile consists of distinct horizons with characteristic properties
  • Horizon = each layer of soil
  • Soil profile = the cross-section of soil as a whole
  • Up to six major horizons may occur in a soil profile
    • Topsoil = inorganic and organic material most nutritive for plants
    • Leaching = dissolved particles move down through horizons
soils are characterized in many ways
Soils are characterized in many ways
  • Soils are classified based on color, texture, structure, and pH
  • Soil color = indicates its composition and fertility
    • Black or dark brown = rich in organic matter
    • Pale gray or white = indicates leaching
  • Soil texture = determined by the size of particles
    • From smallest to largest = clay, silt, sand
    • Loam = soil with an even mixture of the three
    • Influences how easy it is to cultivate and let air and water travel through the soil
soil texture classification
Soil texture classification

Silty soils with medium-size pores, or loamy soils with mixtures of pore sizes are best for plant growth and crop agriculture

soil structure and ph
Soil structure and pH
  • Soil structure = a measure of soil’s “clumpiness”
    • Large clumps can discourage plant roots
    • Repeated tilling compacts soil, decreasing its water-absorbing capabilities
    • Plowpan = a hard layer resulting from repeated plowing that resists water infiltration and root penetration
  • Soil pH = influences a soil’s ability to support plant growth
    • Soils that are too acidic or basic can kill plants
soil properties affect plant growth and agriculture
Soil properties affect plant growth and agriculture.
  • Rainforests have high primary productivity, but the nutrients are in plants, not the soil
    • Rain leaches minerals and nutrients deeper into the soil, reducing their accessibility to roots
    • Swidden agriculture = cultivation of a plot for a few years and then letting it regrow into forest
  • Temperate grasslands have lower rainfall and less nutrient leaching
erosion degrades ecosystems and agriculture
Erosion degrades ecosystems and agriculture
  • Deposition = the arrival of eroded material at its new location
  • Flowing water deposits sediment in river valleys and deltas
    • Floodplains are excellent for farming
  • But, erosion is a problem because it occurs faster than new soil is formed
  • Erosion increases through: excessive tilling, overgrazing, and clearing forests
soil erodes by several methods involving agricultural practices thus lowering crop yields
Soil erodes by several methods involving agricultural practices thus lowering crop yields.
  • Plants protect soils form erosion
    • Removing plants accelerates erosion
  • Rill erosion moves the most topsoil, followed by sheet and splash forms of erosion
  • Water erosion occurs most easily on steep slopes
  • Erosion in the U.S. declined between 1982 and 2001
    • Soil conservation measures

Despite conservation measures, the U.S. still loses 6 tons of soil for every ton of grain harvested

various types of soil erosion
Various types of soil erosion





soil erosion is a global problem
Soil erosion is a global problem
  • Humans are the primary cause of erosion
    • It is occurring at unnaturally high rates
  • In Africa, erosion over the next 40 years could reduce crop yields by half
    • Coupled with rapid population growth, some observers describe the future of agriculture as a crisis situation
desertification affects a large portion of the world s soils especially those in arid regions
Desertification… affects a large portion of the world’s soils, especially those in arid regions.
  • Desertification = a loss of more than 10% productivity
    • Erosion, soil compaction, forest removal, overgrazing, salinization, climate change, depletion of water sources
  • Most prone areas = arid and semiarid lands
desertification has high costs
Desertification has high costs
  • Desertification affects 1/3 of the planet’s land area
    • In over 100 countries
  • Costs tens of billions of dollars each year
    • China loses over $6.5 billion/year alone from goat overgrazing
    • In Kenya, 80% of he land is vulnerable to desertification from overgrazing and deforestation
Irrigation: boosted productivity, but problems… i.e., waterlogging and salinization which lower crop yields and are difficult to mitigate.
  • Irrigation = Artificially providing water to support agriculture
    • Unproductive regions become farmland
  • Waterlogging = over-irrigated soils
    • Water suffocates roots
  • Salinization = the buildup of salts in surface soil layers
    • Worse in arid areas

Salinization inhibits production of 20% of all irrigated cropland, costing more than $11 billion/year

salinization prevention
Salinization prevention
  • It is easier and cheaper to prevent salinization than fix it
  • Do not plant water-guzzling crops in sensitive areas
  • Irrigate with low-salt water
  • Irrigate efficiently, supplying only water that the crop requires
    • Drip irrigation targets water directly to plants
Fertilizers boost yields but… over-fertilizing can cause pollution problems that affect ecosystems and human health.
  • Fertilizer = substances that contain essential nutrients
  • Inorganic fertilizers = mined or synthetically manufactured mineral supplements
  • Organic fertilizers = the remains or wastes of organisms
    • manure, crop residues, fresh vegetation
    • Compost = produced when decomposers break down organic matter

Applying synthetic fertilizer, vs.

Planting rye, a “green manure”

overapplication of fertilizer
Overapplication of Fertilizer
  • Inorganic fertilizer use has skyrocketed
  • Overapplying fertilizer can ruin the soil and severely pollute several areas
  • Runoff causes eutrophication in nearby water systems
  • Nitrates leach through soil and contaminate groundwater
  • Nitrates can also volatilize (evaporate) into the air
overgrazing causes soil degradation on grasslands and impacts native ecosystems
Overgrazing causes soil degradation on grasslands and impacts native ecosystems
  • Overgrazing = too many animals eat too much of the plant cover
    • Impedes plant regrowth
  • A leading cause of soil degradation
  • Government subsidies provide few incentives to protect rangeland

70% of the world’s rangeland is classified as degraded

effects of overgrazing can be striking
Effects of overgrazing can be striking
  • Non-native invasive species invade
    • Less palatable to livestock
    • Out compete native vegetation

Ungrazed plot

Grazed plot

forestry impacts soil such as steep slope cutting
Forestry impacts soil… such as steep slope cutting.

Along withfarming and ranching, forestry impacts soils

Clear-cutting = the removal of all trees from an area at once

Leads to soil erosion, especially on steep slopes

Modern methods remove fewer trees over longer periods of time

Minimizes soil erosion

define the terms crop rotation and contour farming
Define the terms crop rotation and contour farming.

Crop Rotation

The practice of alternating the kind of crop grown in a particular field from one season or year to the next.

Contour Farming

Plowing land along topographic contours, perpendicular to the slope—as much in the horizontal plane as possible, thereby decreasing the erosion rate.

the dust bowl inspired scientist and farmers to develop better ways to conserve topsoil
The Dust Bowl inspired scientist and farmers to develop better ways to conserve topsoil.
  • In the late 19th and early 20th centuries, settlers arrived in Oklahoma, Texas, Kansas, New Mexico and Colorado
  • Grew wheat, grazed cattle
    • Removed vegetation
  • A drought in the 1930s made conditions worse
  • Thousands of farmers left their land and had to rely on governmental help
protecting soil crop rotation and contour farming
Protecting soil: crop rotation and contour farming
  • Crop Rotation = alternating the crops grown field from one season or year to the next,
    • Cover crops protect soil when main crops aren’t planted
    • Wheat or corn and soybeans
  • Contour Farming = plowing furrows sideways across a hillside, perpendicular to its slope, to prevent rills and gullies
protecting soil terracing and intercropping
Protecting soil: terracing and intercropping
  • Terracing = level platforms are cut into steep hillsides, sometimes with raised edges
    • A “staircase” to contain water
  • Intercropping = planting different types of crops in alternating bands or other spatially mixed arrangements
    • Increases ground cover
protecting soil shelterbelts and reduced tillage
Protecting soil: shelterbelts and reduced tillage
  • Shelterbelts or Windbreaks = rows of trees or other tall, perennial plants that are planted along the edges of fields to slow the wind
    • Alley cropping = shelterbelts + intercropping
  • Reduced Tillage = furrows are cut in the soil, a seed is dropped in and the furrow is closed
    • No-till farming disturbs the soil even less
pros and cons of no till farming
Pros and cons of no-till farming
  • Almost half of U.S. farmland uses no-till farming
  • Benefits: reduced soil erosion, greater crop yields, enhanced soils
  • Negatives: increased use of herbicides and fertilizers
  • But, green manure (dead plants and fertilizer) and rotating crops minimizes the negatives
plant cover reduces erosion
Plant cover reduces erosion
  • Eroding banks along creeks and roadsides are stabilized by planting plants to anchor soil
  • China has the world’s largest tree-planting program
    • It does slow erosion
    • But it does not create ecologically functional forests, because monocultures are planted

Services and governments devise innovative policies and programs to reduce soil erosion and boost crop yields.

  • The Soil Conservation Service
  • Started in 1935, the Service works with farmers to develop conservation plans for farms
    • Assess the land
    • Prepare an integrated plan
    • Work closely with landowners
    • Implement conservation measures
  • Conservation districts = districts operate with federal direction, authorization, and funding, but are organized by the states
conservation districts
Conservation districts
  • Districts implement soil conservation programs to empower local residents to plan and set priorities
  • Natural Resources Conservation Service = 1994 renaming of the Soil Conservation Service
    • Expanded responsibilities include water quality protection and pollution control
    • Serves as a model for efforts around the world
u s programs promote soil conservation
U.S. programs promote soil conservation

Food Security Act of 1985: Farmers that adopt soil conservation plan receive price supports and other benefits

Conservation Reserve Program (1985)

Farmers are paid to place highly erodible land into conservation reserves

Trees and grasses are planted instead of crops

Saves 771 million tons of topsoil per year

Generates income for farmers

Provides habitat for native wildlife

federal agricultural improvement act 1996
Federal Agricultural Improvement Act (1996)

Known as the Freedom to Farm Act

Aimed to reduce subsidies and government influence over farm products

Created the Environmental Quality Incentive Program and Natural Resource Conservation Foundation

Promotes and pays for conservation practices in agriculture

Low-Input Sustainable Agriculture Program (1998)

Provides funding for sustainable agricultural practices for individual farmers

international soil conservation programs
International soil conservation programs

Food and Agriculture Organization (FAO) = the United Nations’ main agricultural program

The FAO’s Farmer-Centered Agricultural Resource Management Program (FAR)…

Helps farmers duplicate agricultural success stories

Uses local communities to educate and encourage farmers to conserve soils and secure the food supply

Supports innovative approaches to resource management and sustainable agriculture in around the world

China, Thailand, Vietnam, Indonesia, Sri Lanka, Nepal


Lesson #6

Lab: Soil Salinization

Students will conduct an experiment to investigate how salinization affects germination of crop seeds, then determine at what salt concentration seeds no longer germinate.


Lab: Soil Salinization


To involve students in a real world scientific investigation in which they design an experiment to determine how the concentration of salt in water affects the germination rate of seeds.


Lab: Soil Salinization

Background Information

Salt buildup is a potential problem on almost all of the irrigated farmland in the United States. Much of the world\'s unused land is in arid or semiarid regions where irrigation would be necessary to grow crops. A small amount of salt in the soil will not affect the germination and growth of crops. Eventually, however, if salt concentrations increase, negative impacts occur. Eventually salt concentrations will affect the germination of seeds. Farmers need to know the relationship between the salt concentration and the percent of seeds that will germinate.

Salt kills germinating seedlings by removing the H2O from their cells. There are several salts that are responsible but this lab will involve only one, sodium chloride (NaCl). From your results you can assume that other salt concentrations would also affect germination rate. NaCl has a solubility of 35.7g/100 ml of H2O. Ocean water has a concentration of 3.5% which is 3.5g/100 ml of H2O. Freshwater has a concentration of 0.005% salt, which is 0.005g/100 ml of H2O.


Lab: Soil Salinization


1) After reading the first part of the lab, the “problem” has been identified. Formulate a hypothesis.

2) Identify the independent and dependent variables. To do this, make a question: What is the effect of the independent variable on the dependent variable? This will tell not only the variables but also which variable to put on each axis of the graph. Remember, the x-axis is the horizontal axis and always is the independent variable. The y-axis is the vertical axis and is the dependent variable. (See Analysis Questions 2-3).

3) Decide what will be used as a control. Identify the constants in the experiment. (See Analysis Question #1).

4) Keep accurate data tables and check on the experiment daily.


Lab: Soil Salinization

  • Materials
    • Zip-top bags or Petri dishes
    • Serial dilutions of salt concentrations
    • Graduated cylinders
    • Balances
    • Plastic spoons
    • Flasks or beakers
    • Radish, squash or wheat seeds
    • Permanent markers

Lab: Soil Salinization

  • Procedure
  • 1) Gather materials, and label each bag or Petri dish with the lab group number and period.
  • 2) Count five seeds per bag or Petri dish.
  • 3) Place five seeds onto each paper towel, fold over the towels, place in each Petri dish or bag, and label.
  • 4) Solutions must be made with the following concentrations of salt per 100 ml of water :0, 1, 2, 3, 4.1, 4.2, 4.4, and 5 g. (Don’t do this yet – read step 4c).
    • a) Each lab group will be assigned to mix one or two solution concentrations (depending on the number of groups), making enough to share with the class.
    • b) Mix enough for all groups. Each group needs 20 ml of solution. Be careful: if your solution is incorrectly mixed, you will ruin it for the entire class, since everyone will be using some of your solution.
    • c) If there are six lab groups, you will need 120 ml of water. Convert the original amounts of salt using this format to solve for x:
  • (Example) 2 g = x g
  • 100 ml 120 ml
    • d) Using a balance, weigh out the adjusted amounts of salt.
    • e) Mix the water with the salt and stir until completely dissolved.

Lab: Soil Salinization

  • From the completed data table, draw two graphs:
    • 1) GRAPH 1: Construct a line graph on which you compare the % of salt solution on the x-axis with the number of seeds which germinated on the y-axis. Give the graph a title and label the axes.
    • 2) GRAPH 2: Construct a bar graph comparing the percentage of salt solution on the x-axis with the % of seeds that germinated on the y-axis.

Lab: Soil Salinization

  • Analysis Questions
    • 1) What is the control group in this experiment?
    • 2) What is the dependent variable in this experiment?
    • 3) What is the independent variable in this experiment?
    • 4) Does there seem to be a relationship between the number of seeds which germinated and the concentration of the salt water? If so, what is that relationship?
    • 5) Does there seem to be a relationship between the % that germinated and the concentration of the salt water? If so, what?
    • 6) Did your experiment support your hypothesis? Explain.
    • 7) Can you think of any errors that might have occurred that would invalidate your experiment? If so what were they and how might they be corrected?
    • 8) Explain why increasing levels of salt concentrations affect seed growth and why irrigation seems to be the main cause of this. (Use other sources, if necessary, but cite them.)
    • 9) Do you think all seeds would be affected in similar ways as the ones you used?
    • 10) When soil becomes too salty, what are some methods of remediation?

Lab: Soil Salinization

Data Table 1: Daily Log


Lab: Soil Salinization

Data Table 2: Summary of Results