Ecology

Ecology is the study of how living things(biotic factors) interact with their non-living environment(abiotic factors). This includes the study of the various ecosystems and biomes. After you have studied these, you take a written test. Last year's topic (2009) it is Deserts and Grasslands. This year (2010) it is Grasslands and Taiga. For both of the biomes, you should know the main nutrients found there and their cycles, animals and plants found there along with their adaptations, life zones, and other common processes found there.

Grasslands:

Taiga:

Food Web
On many of the Ecology tests, you were given around a dozen organisms and you had to organize them into a food web. For 2009, the theme is grasslands and deserts, so you should have a general idea of the organisms that inhabit both areas, and which organism consumes the other (ex. shrub -> shrew -> snake -> hawk)

Ecology Definitions
Know how to apply all of below to defining variables, analyzing data from graphs and tables, presenting data in graphs and tables, forming hypotheses, and making calculations and predictions


 * Succession:The replacement of one community by another, developing toward a climax
 * Primary:the ecological succession of vegetation that occurs in passing from barren earth or water to a climax community
 * Secondary:The development of biotic communities in an area where the natural vegetation has been removed or destroyed but where soil is present

More Terms

 * Extinction-gone forever


 * Selection:In the context of evolution, certain traits or alleles of a species may be subject to selection. Under selection, individuals with advantageous or "adaptive" traits tend to be more successful than their peers reproductively--meaning they contribute more offspring to the succeeding generation than others do
 * Natural:The differential survival and reproduction of organisms with genetic characteristics that enable them to better utilize environmental resources
 * Stabilizing:Stabilizing selection is a type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait
 * Disruptive:Disruptive selection is a type of natural selection that simultaneously favors individuals at both extremes of the distribution. When disruptive selection operates, individuals at the extremes contribute more offspring than those in the center, producing two peaks in the distribution of a particular trait
 * Directional:In population genetics, directional selection occurs when natural selection favors a single allele and therefore allele frequency continuously shift in one direction.
 * Artificial:The process in which breeders choose the variants to be used to produce succeeding generations
 * Limiting Factors:A factor that limits a population's growth; i.e.resources and shelter


 * Biodiversity:The number and variety of organisms within one region

Ecology Graphs and Charts

 * Survival Curves: Graph of the probability of survival (y-axis) versus time (x-axis). Some basic life history strategies can be seen from the basic shape of this graph.  Type I organisms have lower mortality rate at low ages which gradually increases with age.  Type II organisms have mortality rates that stay the same throughout life.  Type III organisms have the largest mortality rates at birth.  Most survivalship curves are combinations of more than one type of organism.  The three general shapes can be seen below.




 * Life Table:an age-specific death schedule. Such a schedule is often converted to a more palatable survivorship schedule. For each age interval there is an predicted life expectancy or survivorship. From a life table, one can produce a survival curve.


 * Biomes:See http://www.ucmp.berkeley.edu/glossary/gloss5/biome/index.html]

Population Growth
Population growth deals with how the size of a population changes over time. Intrinsic rate of growth (r-max) is the rate of growth under ideal conditions.
 * Exponential growth occurs when the growth rate remains the same while the population grows. It creates a J shaped curve (shown in red below).
 * Logistic growth occurs when the growth rate decreases as the population grows due to density-dependent factors (factors increasing mortality rate as population grows such as predation rates, competition, and disease). This creates an S-shaped curve (shown in blue below).  It is the most common type of population growth.



Life History Strategies

 * Age of Reproduction:the average age in an organism when it becomes capable of reproduction ( For example, population A might have many more members than population However, all the members of A might be post-reproductive, whereas population B might consist of mostly prereproductive and reproductive age individuals. Population A might be in danger of extinction)
 * r-selected organisms:put most of their energy into rapid growth and reproduction. This is common of organisms that occupy unpredictable environments, e.g. weeds are usually annuals with rapid growth and early reproduction. They produce large number of seeds containing few stored nutrients
 * K-selected organisms:put most of their energy into growth. They are common in stable environments near carrying capacity, e.g. long lived trees such as redwoods take many years of growth to reach reproductive age


 * Seed Dispersal:the method by which a plant scatters its offspring away from the parent plant to reduce competition. Methods include: wind, insects, animals, tension, and water
 * Wind:Some seeds are carried to a new place by the wind. These seeds are very light. The seeds of the orchid are almost as fine as dust. Many have hairy growths which act like little parachutes and carry the seeds far away from the parent plant.
 * Water:Fruits which float such as those of the water lily and the coconut palm are carried by water. Coconuts can travel for thousands of kilometers across seas and oceans. The original coconut palms on South Sea islands grew from fruits which were carried there from the mainland by ocean currents.
 * Animals/Insects:The animal eats the fruit but only the juicy part is digested. The stones and pips pass through the animal's digestive system and are excreted to form new plants. This can be far away from the parent plant.
 * Explosions/Tension/Mechanical:Some plants have pods that explode when ripe and shoot out the seeds. Lupins, gorse and broom scatter their seeds in this way. Pea and bean plants also keep their seeds in a pod. When the seeds are ripe and the pod has dried, the pod bursts open and the peas and beans are scattered.
 * Fire:To survive fire some plants have adaptive traits that allow them to reproduce or regenerate. An adaptive trait is a behavior, physical feature or some other characteristic that helps a plant or animal survive and make the most of its habitat. When fire occurs, animals have the ability to fly, run away or burrow deep into the ground. Plants cannot do this and so have adapted other ways of surviving. The way a plant stores its seeds and disperses them is an example of a fire adaptive strategy. The intensity of the fire ( it is important the fire reaches the right temperature) is crucial to the seeds dispersal. Also important is how often the fires occur.

Global Warming
Greenhouse Effect: Energy from the sun drives the earth�s weather and climate, and heats the earth�s surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse. Without this natural �greenhouse effect,� temperatures would be much lower than they are now, and life as known today would not be possible. Instead, thanks to greenhouse gases, the earth�s average temperature is a more hospitable 60�F.

Possible Causes: Problems arise when the atmospheric concentration of greenhouse gases increases. Since the the industrial revolution, atmospheric concentrations of carbon dioxide have increased nearly 30%, methane concentrations have more than doubled, and nitrous oxide concentrations have risen by about 15%. These increases have enhanced the heat-trapping capability of the earth�s atmosphere. Sulfate aerosols, a common air pollutant, cool the atmosphere by reflecting light back into space; however, sulfates are short-lived in the atmosphere and vary regionally. Scientists generally believe that the combustion of fossil fuels and other human activities are the primary reason for the increased concentration of carbon dioxide. Plant respiration and the decomposition of organic matter release more than 10 times the CO2 released by human activities; but these releases have generally been in balance during the centuries leading up to the industrial revolution with carbon dioxide absorbed by terrestrial vegetation and the oceans. Fossil fuels burned to run cars and trucks, heat homes and businesses, and power factories are responsible for about 98% of U.S. carbon dioxide emissions, 24% of methane emissions, and 18% of nitrous oxide emissions. Increased agriculture, deforestation, landfills, industrial production, and mining also contribute a significant share of emissions. In 1997, the United States emitted about one-fifth of total global greenhouse gases.

Effects of Climate Change: Mean surface temperatures have increased 0.5-1.0�F since the late 19th century. The 20th century's 10 warmest years all occurred in the last 15 years of the century. Of these, 1998 was the warmest year on record. The snow cover in the Northern Hemisphere and floating ice in the Arctic Ocean have decreased. Globally, sea level has risen 4-8 inches over the past century. Worldwide precipitation over land has increased by about one percent. The frequency of extreme rainfall events has increased throughout much of the United States. Increasing concentrations of greenhouse gases are likely to accelerate the rate of climate change. Scientists expect that the average global surface temperature could rise 1-4.5�F (0.6-2.5�C) in the next fifty years, and 2.2-10�F (1.4-5.8�C) in the next century, with significant regional variation. Evaporation will increase as the climate warms, which will increase average global precipitation. Soil moisture is likely to decline in many regions, and intense rainstorms are likely to become more frequent. Sea level is likely to rise two feet along most of the U.S. coast.

Invasive Species
A species that has moved into an area and reproduced so aggressively that it has replaced some of the original species. For example if we introduced one species to a new environment the already adapted species to that area would be forced out. This practice can be produced by lost of habitat.

Acid Rain
Acid rain is a broad term used to describe several ways that acids fall out of the atmosphere. A more precise term is acid deposition, which has two parts: wet and dry. Wet deposition refers to acidic rain, fog, and snow. As this acidic water flows over and through the ground, it affects a variety of plants and animals. The strength of the effects depend on many factors, including how acidic the water is, the chemistry and buffering capacity of the soils involved, and the types of fish, trees, and other living things that rely on the water. Dry deposition refers to acidic gases and particles. About half of the acidity in the atmosphere falls back to earth through dry deposition. The wind blows these acidic particles and gases onto buildings, cars, homes, and trees. Dry deposited gases and particles can also be washed from trees and other surfaces by rainstorms. When that happens, the runoff water adds those acids to the acid rain, making the combination more acidic than the falling rain alone. Prevailing winds blow the compounds that cause both wet and dry acid deposition across state and national borders, and sometimes over hundreds of miles.

Scientists discovered, and have confirmed, that sulfur dioxide (SO2) and nitrogen oxides (NOx) are the primary causes of acid rain. In the US, About 2/3 of all SO2 and 1/4 of all NOx comes from electric power generation that relies on burning fossil fuels like coal. Acid rain occurs when these gases react in the atmosphere with water, oxygen, and other chemicals to form various acidic compounds. Sunlight increases the rate of most of these reactions. The result is a mild solution of sulfuric acid and nitric acid.

Erosion
The wearing away of land or soil by the action of wind, water, or ice. Soil erosion is a natural process. It becomes a problem when human activity causes it to occur much faster than under natural conditions.

Causes of Soil Erosion
Wind and water are the main agents of soil erosion. The amount of soil they can carry away is influenced by two related factors:
 * speed - the faster either moves, the more soil it can erode;
 * plant cover - plants protect the soil and in their absence wind and water can do much more damage.

The Importance of Plants
Plants provide protective cover on the land and prevent soil erosion for the following reasons: The loss of protective vegetation through deforestation, over-grazing, ploughing, and fire makes soil vulnerable to being swept away by wind and water. In addition, over-cultivation and compaction cause the soil to lose its structure and cohesion and it becomes more easily eroded. Erosion will remove the top-soil first. Once this nutrient-rich layer of soil is gone, few plants will grow in the soil again. Without soil and plants the land becomes desert-like and unable to support life - this process is called desertification. It is very difficult and often impossible to restore desertified land.
 * plants slow down water as it flows over the land (runoff) and this allows much of the rain to soak into the ground;
 * plant roots hold the soil in position and prevent it from being washed away;
 * plants break the impact of a raindrop before it hits the soil, thus reducing its ability to erode;
 * plants in wetlands and on the banks of rivers are of particular importance as they slow down the flow of the water and their roots bind the soil, thus preventing erosion.

Preventing Soil Erosion
Preventing soil erosion requires political, economic and technical changes. Political and economic changes need to address the distribution of land in South Africa as well as the possibility of incentives to encourage farmers to manage their land sustainably. Aspects of technical changes include:
 * the use of contour ploughing and wind breaks;
 * leaving unploughed grass strips between ploughed land;
 * making sure that there are always plants growing on the soil, and that the soil is rich in humus (decaying plant and animal remains). This organic matter is the "glue" that binds the soil particles together and plays an important part in preventing erosion; ->* avoiding overgrazing and the over-use of crop lands;
 * allowing indigenous plants to grow along the river banks instead of ploughing and planting crops right up to the water's edge;
 * encouraging biological diversity by planting several different types of plants together;
 * conservation of wetlands.

Where They Are
Grasslands comprise most of the central United States. Here is a map of that:

Food Consumption
Here is an example of a grassland food pyramid:

Producers
Allium canadense

Allium canadense(Known as Wild Onion and Meadow Garlic) is is a perennial plant native to North America.


 * It has an edible bulb covered with a dense skin of brown fibers and tastes like an onion. The plant also has strong, onion-like odor.


 * The narrow, grass-like leaves originate near the base of the stem, which is topped by a dome-like cluster of star-shaped, pink or white flowers.


 * It typically flowers in the spring and early summer, from May to June.


 * Though the plant is edible, it pays to be careful in identifying it as there are several look-a-likes.


 * The juice of the plant is used as a moth repellent, and the whole plant is said to repel insects and moles. The plant can be rubbed on exposed parts of the body to protect them from the bites of scorpions and lizards.

Andropogon gerardii

Andropogon gerardii (Known as Big Bluestem) is a tall grass native to much of the prairie and Great Plains regions of North America.


 * Big bluestem is tolerant of a wide range of soils and moisture.


 * Depending on soil and moisture conditions, it grows to a height of 1 � 3m (3 � 10 ft).


 * Big Bluestem is a perennial grass.


 * The stem base turns to a blue-purple as it matures.


 * The seed heads have three spike-like projections, resulting in another common name for big bluestem � "turkey foot."


 * The roots are deep, and the plants send out strong, tough rhizomes, so it forms very strong sod.


 * Big bluestem is also called tallgrass or simply called prairie tallgrass.


 * Big bluestem is a late-successional grass in prairie ecosystems.


 * It grows in tall, dense stands that shade out other plant species. These stands tend to gradually increase in size over time, unless a disturbance (such as fire) allows other plant species to re-establish themselves.


 * Bluestem, which has many variants, is considered to be good forage for horses and cattle, and can also be cut and used for hay.


 * It has a high protein level.


 * While not considered the highest quality native forage found in the United States, it has long been considered a desirable and ecologically important grass by cattle ranchers and range-land ecologists.


 * Bluestem grass is also used by landscapers and home owners who want to create a 'native' look in their lawns and gardens.


 * Due to its high biomass, big bluestem is being considered as a potential feedstock for ethanol production.

Anemone canadensis

Anemone canadensis (Known as Canada Anemone, Round-headed anemone or Crowfoot) is a spring to early summer flowering plant that can sometimes be found flowering till late summer in the Genus Anemone and family Ranunculaceae.


 * It is native from Eastern half of northern North America.


 * Its sometime grown in garden for its attractive bright white flowers.


 * Plants grow 20-80 cm tall from ascending caudices formed on long running rhizomes, the rhizomes ascending to horizontal some what fleshy it texture and golden-brown in color.


 * Basal leaves are simple and deeply divided with 1 to 5 produced per caudice.


 * The leaf petioles 8-22(-37) cm long. Leaf blades orbiculate in shape and 4-10 cm wide and 5-15(-20) cm long.


 * The leaves have sagittate to nearly truncate shaped bases and serrated margins.


 * The leaf surfaces are covered with short, soft hairs (puberulous), with the undersides more densely covered.


 * Each leaf with normally 3 segments that are lanceolate to oblanceolate in shape.


 * Inflorescences with 1 to 3+ flowers, rarely grouped into cymes.


 * The stem holding the flowers called peduncles with hairs puberulous to villous.


 * The flowers with 3 stemless involucral bracts, sometimes having secondary involucres with 2 bracts, remotely subtending the flowers.


 * The bracts simple, more or less similar in shape to the basal leaves, being broadly obtriangular and 3-cleft and 3-10 cm wide.


 * The bases of the bracts are broadly cuneate in shape and fused together with margins sharply but irregularly serrated and incised with acuminate tips, surfaces puberulous, more so underneath; segments 3, lanceolate to oblanceolate; lateral segments unlobed or 1�-lobed; ultimate lobes (8-)10-15(-20) mm long.


 * The bright white colored flowers are composed of 5 sepals normally, that are obovate in shape, each (8-)10-20(-25) mm long and 5-15 mm wide, hairy or hairless.


 * The flowers have 80-100 stamens placed in the middle of the sepals.


 * After blooming fruits are produced in spheric to ovoid shaped heads of achenes that are green in color, the pedicel or stem holding the cluster of seeds (fruits) is 7.5-11.5 cm long.


 * Each achene is obovoid to ellipsoid in shape, (2.5-)3-6 long and 3.5-6 mm wide, with winged margins, and has a straight beak 2-6 mm long.


 * This species of Anemone is found growing in meadows, along roadsides, and in low shrubby areas were the soil is moisture retentive, it can spread by way of underground running rhizomes to form large thick colonies or spread-out along shorelines in long rows.


 * When growing amongst thick vegetation plants are sparsely flowering.


 * Anemone canadensis is distinguishable from others in the genus by its sessile (stalkless) 5-7 lobed leaves which surround the stem.


 * The main range is throughout Southern Canada to Missouri, Illinois, western Virginia and northern New Jersey although it can be found as far West as British Columbia and as far South as New Mexico.


 * In former times it was used medically by North American Indigenous peoples as an astringent and as a styptic for wounds, sores, and nosebleeds; and as an eyewash.


 * The root was respected by Plains tribes and used for many ailments.


 * It is likely that most Anemones contain the caustic irritants of the Ranunculaceae family.

Apocynum cannabinum

Apocynum cannabinum (Known as Dogbane, Amy Root, Hemp Dogbane, Rheumatism Root, or Wild Cotton)is a perennial herbaceous plant that grows throughout much of North America, in the southern half of Canada and throughout the United States.


 * It grows up to 2 meters tall.


 * It prefers moist places.


 * It is a poisonous plant; the name means "poisonous to dogs".


 * All parts of the plant are poisonous and can cause cardiac arrest if ingested.


 * The stems are reddish and contain a milky latex capable of causing skin blisters.


 * The leaves are opposite, simple broad lanceolate, 7-15 cm long and 3-5 cm broad, entire, and smooth on top with white hairs on the underside.


 * The flowers are produced in mid summer, with large sepals, and a five-lobed white corolla.


 * It grows in open wooded areas, ditches, and hillsides; in gardens it can be invasive, growing from spreading roots.


 * When growing among corn, Apocynum cannabinum can reduce yields by up to 10% and when growing among soybeans, by up to 40%.


 * It can be controlled through mechanical means, although it is difficult to control with herbicides.


 * Canadian hemp was used as a source of fiber by Native Americans, to make hunting nets, fishing lines, clothing, and twine.


 * It was also used in herbal medicine to treat syphilis, rheumatism, intestinal worms, fever, asthma, and dysentery.


 * Although the toxins from the plant can cause nausea and catharsis, it has also been used for slowing the pulse.

Asclepias incarnata

Asclepias incarnata (Known as Swamp Milkweed, Rose Milkweed, Swamp Silkweed, or White Indian Hemp) is a herbaceous, perennial plant species native to North America.


 * It is found growing in damp to wet soils and also is cultivated as a garden plant for its attractive flowers, which are visited by butterflies and other pollinators due to its copious production of nectar.


 * Like most other milkweeds, it has sap containing toxic chemicals, a characteristic that repels insects and herbivorous animals.


 * Swamp milkweed is an upright, 100- to 150-centimeter (39- to 59-inches) tall plant, growing from thick, fleshy, white roots.


 * Typically, its stems are branched and the clump forming plants emerge in late spring after most other plants have begun growth for the year.


 * The oppositely arranged leaves are 7 to 15 centimeters (2.75 to 6 inches) long and are narrow and lance-shaped, with the ends tapering to a sharp point.


 * The plants bloom in early to mid-summer, producing small, fragrant, pink to mauve (sometimes white) colored flowers in rounded umbels.
 * The flower color may vary from darker shades of purple to soft, pinkish purple and a white flowering form exists as well.


 * The flowers have five reflexed petals and an elevated central crown.


 * After blooming, green seed pods, approximately 12 centimeters (4.5 inches) long, are produced that when ripe, split open.


 * They then release light to dark brown, flat seeds that are attached to silver-white silky-hairs ideal for catching the wind.


 * This natural mechanism for seed dispersal is similar to that used by other milkweed plants.


 * Swamp milkweed prefers moisture retentive to damp soils in full sun to partial shade and typically, is found growing wild near the edges of ponds, lakes, streams, and low areas�or along ditches.


 * It is one of the best attractors of the Monarch Butterfly, which feeds on the flowers and lays her eggs on the plants.


 * The emerging caterpillars feed on the leaves.


 * The plants have specialized roots for living in heavy wet soils.


 * The scented, thick, white roots are adapted to live in environments low in oxygen.


 * Blooming occurs in mid to late summer and after blooming; long, relatively thin, rounded, pods are produced that grow uprightly.


 * The pods split open in late summer to late fall, releasing seeds that are attached to silky hairs, which act as parachutes that carry the seeds on the currents of the wind.


 * This species is cultivated frequently and a number of cultivars are available.


 * They are used especially in gardens designed to attract butterflies.


 * The nectar of the plant attracts many other species of butterflies and insects as well.


 * The plants are also sold as freshly cut flowers, mostly for their long-lasting flower display, but sometimes, for the distinctive seed pods.

Asclepias syriaca

Asclepias syriaca (Known as Common Milkweed, Butterfly flower, Silkweed, Silky Swallow-wort, or Virginia Silkweed) is a herbaceous plant species. It is in the genus Asclepias, making it a type of milkweed.


 * This species is native to most of North America east of the Rocky Mountains, excluding the drier parts of the Prairies.


 * It grows in sandy soils and appreciates lots of sunlight.


 * It was one of the earliest North American species described in Cornut's 1635 Canadensium plantarum historia.


 * The specific epithet was reused by Linnaeus due to Cornut's confusion with a species from Asia Minor.


 * Common milkweed is a herbaceous perennial plant growing to 1-2 m tall from a rhizome.


 * The stem and all parts of the plants produce a white latex when broken.


 * The leaves are opposite, simple broad ovate-lanceolate, 7-25 cm long and 3-12 cm broad, usually with an undulate margin and a red-colored main vein.


 * They have a very short petiole and a velvety underside.


 * The flowers are grouped in several spherical umbels with numerous flowers in each umbel.


 * The individual flowers are small, 1-2 cm diameter, perfumed, with five cornate hoods.


 * The seeds are attached to long, white flossy hairs and encased in large follicles.

Calamagrostis canadensis

Calamagrostis canadensis (Known as Bluejoint or Canadian Redgrass) is a species of grass native to most of northern North America, including most all of Canada and all of the continental United States except for the South.


 * It is a perennial grass with a branching stem reaching heights between 60 centimeters and 1.5 meters.


 * The flat, drooping leaves are rough with tiny hairs.


 * The inflorescence is up to 25 centimeters long and may be open and loose or narrow and densely packed with spikelets.


 * Each spikelet is about half a centimeter long and purplish in color.


 * It is a palatable food plant for livestock and wild grazing animals.


 * It is a tough rhizomatous grass that provides soil stability in wet areas and is one of the first plants to reestablish on sites of recent oil spills.


 * It can be a nuisance on sites of forest revegetation because it can outcompete conifer seedlings.

Caltha palustris

Caltha palustris (Known as Marsh Marigold or Kingcup) belongs to the Ranunculaceae (buttercup family). It is native to temperate regions of the Northern Hemisphere (Europe including Iceland and Arctic Russia, temperate and Arctic Asia, and North America).


 * It grows in wet, boggy places, such as marshes, fens, ditches and wet woods.


 * It becomes most luxuriant in partial shade, but is rare on peat.


 * In the UK, it is probably one of the most ancient British native plants, surviving the glaciations and flourishing after the last retreat of the ice, in a landscape inundated with glacial meltwaters.


 * The plant is a herbaceous perennial growing to 80 cm tall.


 * The leaves are rounded to kidney-shaped, 3-20 cm across, with a bluntly serrated margin and a thick, waxy texture.


 * Stems are hollow.


 * The flowers are yellow, 2-5 cm diameter, with 4-9 (mostly 5) petaloid sepals and many yellow stamens; they are borne in early spring to late summer.


 * The flowers are visited by a great variety of insects for pollen and for the nectar secreted from small depressions, one on each side of each carpel.


 * Carpels form into green sac-like follicles to 1 cm long, each opening to release several seeds.


 * It flowers early April and May and is very valuable to insects at this time as they provide nectar and pollen to them.

1st Level Consumers
Cynomys gunnisoni

Cynomys gunnisoni (Known as Gunnison's Prairie Dog) is one of five species of the Prairie Dog. Predominantly related to the North American and Eurasian ground squirrels, this species belongs to the squirrel family of rodents.


 * Gunnison�s Prairie Dogs are primarily distrubuted in the four corners of North America: the region where Utah, Colorado, New Mexico, and Arizona meet.


 * Gunnison�s Prairie Dogs possess a body that is stout with a very short tail that measures 1.25 to 2.25 inches (3 to 6 centimeters).


 * Their overall size differs anywhere from around 12 to 14 inches (30 to 37 centimeters).


 * However, on average males are usually larger in size than females.


 * This breed weighs from a range of 1.5 to 2.5 lbs (0.5 to 1 kg).


 * A Gunnison's prairie dog skull holds 22 teeth. The animals have 5 pairs of mammary glands.

Sample Questions


The graph above relates nitrate concentration in runoff water near a forest to time. In this experiment, forest A experienced deforestation completed in 1925. Forest B experienced little to no deforestation.

1.Explain the cause for the different concentrations of nitrate in the two ecosystems.

2.What is a possible cause for the increase of nitrate concentration in the runoff water in ecosystem B?



1. Why are similar warblers in the above diagram able to coexist in the same ecosystem?

2. This strategy that allows them to live together is known as __________.

Links
http://geology.mines.edu/courses/sygn101/notes_page.html
 * Earth and Environmental Systems podcast show notes, look for episodes 29, 33-38

2007 Resources
Forest:

http://www.ucmp.berkeley.edu/exhibits/biomes/forests.php

http://www.mbgnet.net/sets/rforest/index.htm

Marine:

http://darter.ocps.net/classroom/klenk/Contents.htm

http://www.connaughton.washcoll.edu/academics/marine/marinelectures.html

http://www.mbgnet.net/salt/sandy/indexfr.htm

Estuaries:

http://www.estuaries.gov/pdf/energyflow.pdf

http://inlet.geol.sc.edu/estecohp.html

http://www.estuaries.gov/about.html

2009 Resources
Deserts:

http://www.desertusa.com/life.html (Introductory desert material)

http://www.western.edu/faculty/jsowell/desertecology/index.html (good study guide!)

Grasslands: Ecology Glossary