Ecological Succession

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• Ecological Succession
• Succession Gradual change in species occupying
  an area. Due to changes in 1 or more abiotic or
  biotic factors favoring some species over
  another.
• Primary Succession Gradual establishment of an
  ecosystem where one did not exist before (Ex on
  bare rock).
• Secondary Succession Gradual reestablishment of
  an ecosystem from an area where it previously
  existed.
• Pioneer species Plant or animal species that are
  the first to occupy a newly exposed or disturbed
  area.
• Climax species Last stage of succession. One in
  which populations of all organisms are in balance
  w/ each other existing abiotic factors.
• Examples Old Growth Forest

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• Factors Affecting the Distribution of
• Animal Species
• Temperature
• Water
• Food supply
• Breeding Nesting Sites
• Territory
• Plant Species
• Temperature
• Quantity of light
• Water
• Soil pH
• Minerals

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Aquatic Biomes

• Biome A large group of ecosystems that share
  the same type of climax community.
• Marine Biomes
• Photic zones (photosynthesis)
• Aphotic zones (Thought to be lifeless wrong!!)
• EstuariesEstuaries are areas where freshwater
  streams or rivers merge with the ocean. This
  mixing of waters with such different salt
  concentrations creates a very interesting and
  unique ecosystem. Microflora like algae, and
  macroflora, such as seaweeds, marsh grasses, and
  mangrove trees (only in the tropics), can be
  found here. Estuaries support a large diversity
  of organisms, including a variety of worms,
  oysters, crabs, and waterfowl.

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Terrestrial Biomes

• Abiotic factors, such as climate, are important
  in determining where a particular biome is
  located. There are longtitudal patterns of
  climate over the Earths surface, and therefore,
  there are also longtitudal patterns of biome
  distribution over the Earths surface. 
• Biomes are often named for their predominant
  vegetation, and all have certain characteristics
  such as microorganisms, fungi, and animals which
  have adapted to their particular environment.  As
  well, biomes also grade into one another, and do
  not usually have sharp boundaries.  In fact, if
  the area of intergradation is large enough, it
  may itself be recognized as a separate biome. 
• In biomes of the same type, but located in
  different areas, the species found there may
  vary.  For example, in the coniferous forests of
  North America, red spruce is common in the east,
  but is not found in other areas.  There, black
  spruce and white spruce are abundant.  Also,
  plants of different families are found in African
  and North American deserts, but the plants do
  resemble one another superficially.  This
  similarity can arise due to convergent evolution,
  the independant development of similarity
  between species as a result of their having
  similar ecological roles and selection
  pressures. 
• Several communities may be represented in patches
  within a biome.  For example, snowfall may break
  branches and small trees and cause openings in a
  coniferous forest, allowing deciduous species to
  grow. 

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Tropical Forest

• Tropical forests are warm, moist tropical
  lowlands found within 23.5 latitude of the
  equator, having both a high temperature and
  rainfall. The average temperature and length of
  daylight vary little during the year, being about
  23C and around 12 hours respectively. The
  rainfall is always over 60 inches per year, and
  can be up to 160 inches. There is a predictable
  daily cycle of cloud buildup and rain.  The soils
  are highly weathered, reddish in colour, and
  contain large amounts of Aluminum and Iron. Rapid
  decomposition occurs, and nutrients are cycled
  quickly, stored mostly in the plant biomass.  The
  tropical rain forest has the greatest diversity
  of species of all communities, perhaps as many as
  all other terrestrial biomes combined. The
  vegetation in tropical rain forests is divided
  into five general layers the trees that emerge
  above the canopy, the high upper canopy or
  topmost continuous layer of foilage, the low-tree
  stratum, the shrub understory, and a ground layer
  of herbaveous plants and ferns. This great plant
  diversity also allows a great animal diversity.
  These include monkeys, sloths, parrots, toucans,
  bats, tapirs, frogs, and a wide variety of
  insects. Terrestrial Biomes
• Tropical forests are threatened by logging, and
  clearing for grazing and agriculture.  Millions
  of hectares of tropical forests are being
  destroyed at an alarming
• rate - more than one half of earths tropical
  rain forest is already gone, and it is likely
  these communities may disappear entirely by the
  end of the decade.  This loss means the loss of
  the biological diversity of the forests. 

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Desert

• Deserts are found at latitudinal positions
  between 15o to 35 North and South of the
  equator, and also in rainshadows.  They are the
  driest of all biomes.  The evaporation exceeds
  rainfall, making it very dry, with less than 30cm
  of rain per year.  Most deserts are very hot, but
  cold deserts also exist.  The hot deserts
  generally experience hot days and cold nights. 
  Hot deserts can be found in the southwest of the
  United States, along the coast of South America,
  in northern Africa, and in the Middle East. 
  There are cold deserts to the west of the Rocky
  Mountains, in eastern Argentina and throughout
  central Asia. 
• The driest deserts receive too little rainfall to
  support any perennial vegetation.  In less arid
  regions, the plant life includes some grasses,
  shrubs, cacti, creosote, and rosette plants. 
  These plants have numerous adaptations to life in
  the desert, including
• deep or spreading roots
• losing leaves (eg. prickly pear, ocotillo)
• thorns
• poisons
• annual habit - seeds
• CAM plants exchange CO2 at night
• Periods of rainfall are marked by sudden and
  spectacular blooms of plants.

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Grassland

• Temperate grasslands are similar to tropical
  savanna, but are found in regions with relatively
  cold winter temperatures.  This biome is found in
  South Africa, Hungary, Argentina, Uraguay,
  Russia, and North America.
• Large vertebrate grazers are the most
  conspicuous, such as bison, antelopes and wild
  horses.  However the most intense grazing of
  grasslands takes place below ground by
  invertebrates, who consume up to four times as
  much as all above ground herbivores. 
• This biome remains grassland, and is not taken
  over by woody shrubs and trees, because of
  seasonal drought, occasional fires, and grazing
  by large mammals.  The soil of grassland is the
  deepest and most fertile in the world. 

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Taiga

• Taiga, also known as coniferous or boreal forest,
  is the largest terrestrial biome on earth.  It
  extends in a broad band across North America,
  Europe, and Asia to the southern border of the
  arctic tundra.  It is also found at cool high
  elevations in the more temperate latitudes, for
  example, in much of the mountainous western
  region of North America.  Long, cold winters, and
  short, occasionally warm, wet summers are typical
  of this region.  The soil is thin, nutrient
  poor,and acidic.    
•   
• There is usually only one or a few species in a
  particular area.  These include different species
  of spruce, pine, or fir, and often there is
  little undergrowth present.  There may also
  occasionally be deciduous species present, such
  as oak, birch, willow, or alder, in a
  particularly wet or disturbed area. 

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Tundra

• Tundra is the coldest of all the biomes. Tundra
  comes from the Finnish word tunturi, meaning
  treeless plain. It is noted for its frost-molded
  landscapes, extremely low temperatures, little
  precipitation, poor nutrients, and short growing
  seasons. Dead organic material functions as a
  nutrient pool. The two major nutrients are
  nitrogen and phosphorus. Nitrogen is created by
  biological fixation, and phosphorus is created by
  precipitation.
• Characteristics of tundra include
• Extremely cold climate
• Low biotic diversity
• Simple vegetation structure
• Limitation of drainage
• Short season of growth and reproduction
• Energy and nutrients in the form of dead organic
  material
• Large population oscillations

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