Communities, Biomes,

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Communities, Biomes, Ecosystems

• Chapter 3

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Ecological Succession
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Ecological Succession

• Stability-the tendency to remain in a more or
  less constant balance due largely to interactions
  among organisms
• Disturbance-a force that alters a biological
  community and usually removes organisms from it
• Ecological succession-the process of community
  change resulting from a disturbance

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Types of Succession

• Primary succession begins from an abiotic
  environment following a cataclysmic disturbance
  (volcanic eruptions or glacier melt) occurs on
  land where no soil exists
• Secondary succession beginning from a major
  disturbance, but all forms of life are not
  destroyed.

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Stages of Succession

• Pioneer plants typically small with short
  lifecycles (annuals), rapid seed dispersal,
  environmental stabilizers lichens and mosses
• Intermediate plants typically longer lived,
  slower seed dispersal, and in woodland systems
  perennials, shrubs.
• Climax plants and animal species are those
  associated with older, more mature ecosystem.

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Effects of Latitudeand Climate
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The Effect of Latitude on Climate

• Earth is tilted on its axis causing solar
  radiation to strike different parts of Earths
  surface at an angle that varies throughout the
  year
• The difference in heat distribution with latitude
  has important effects on Earths climate zones

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The Role of Climate

• Climate-refers to the average, year-after-year
  conditions of temperature and precipitation in a
  particular region
• Weather-day-to-day condition of Earths
  atmosphere at a particular time and place
• Climate is determined by
• The trapping of heat by the atmosphere
• The latitude
• The transport of heat by winds and ocean currents
• The amount of precipitation that results

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Three Main Climate Zones

• Polar zones-cold areas where the suns rays
  strike Earth at a very low angle
• Temperate zones-sit between polar zones and the
  tropics, are more affected by the changing angle
  of the sun during the year, the climate ranges
  from hot to cold, depending on the season
• Tropical zone-also known as the tropics, is near
  the equator, and receive direct or nearly direct
  sunlight year-round, usually warm

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Heat Transport in the Biosphere

• The unequal heating of Earths surface causes air
  (winds) and water (ocean currents) to circulate
  heat throughout the biosphere
• Air rises when heated, sinks when cools forming
  winds air heated near the equator rises, cooler
  air over the poles sinks toward the ground
• Prevailing winds bring warm or cold air to a
  region, affecting its climate

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Heat Transport in the Biosphere

• Similar patterns of heating and cooling occur in
  Earths oceans
• Uneven heating of Earths surface is a major
  factor driving air movements and water currents
• unequal heating of surface waters, and the
  locations and shapes of the continents create
  ocean currents, river-like flow patterns in the
  ocean
• Ocean currents transport heat energy within the
  biosphere
• Continents and other landmasses can also affect
  winds and ocean currents mountain ranges cause
  moist air masses to rise eventually resulting in
  precipitation

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The Greenhouse Effect

• Carbon dioxide, methane, water vapor, and other
  gases trap heat energy and maintain Earths
  temperature range
• The natural insulation in which heat is retained
  by the layer of greenhouse gases is the
  Greenhouse effect
• Greenhouse gases allow solar energy to penetrate
  the atmosphere in the form of sunlight

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The Greenhouse Effect

• Much of the sunlight that hits the surface of
  Earth is converted into heat energy and radiated
  back into the atmosphere
• These same gases do not allow heat energy to pass
  out of the atmosphere as readily as light enters
  it
• The gases trap heat inside Earths atmosphere
  creating a warm blanket causing Earth to become
  warmer than it should

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The Major Biomes
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Tundra

• Northernmost biome
• Permafrost is prime characteristic
• Cold, long, dark winters short, soggy summers,
  strong winds, low precipitation, poorly developed
  soils
• Mosses, lichens, sedges, and short grasses
• Caribou, snowy owl, arctic foxes, lemmings
• Northern North America, Asia, and Europe

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Taiga or Boreal Forest

• Coniferous trees dominate some deciduous trees,
  small, berry-bearing shrubs
• Climate
• Long cold winters
• Short, mild summers
• Moderate precipitation, high humidity, acidic,
  nutrient-poor soils
• Lynx, timberwolves, moose, beavers, songbirds
• North America, Asia, and northern Europe

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Temperate Forest

• Deciduous trees dominate contain some coniferous
  trees flowering shrubs
• Climate
• Year-round precipitation
• Cold to moderate winters
• Warm summers
• Deer, black bear, bobcats, squirrels, raccoons
• Eastern US, southeastern Canada, most of Europe,
  parts of Japan, China, and Australia

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Temperate Woodland and Shrubland

• Characterized by semi-arid climate
• In the open woodlands, large areas of grasses,
  wildflowers ex. Poppies and oak trees
• Communities dominated with shrubs are also known
  as the chapparal
• Fires are a constant threat because of the growth
  of dense, low plants that contain flammable oils
• Hot, dry summers cool, moist, winters thin,
  nutrient, poor soils
• Coyotes, foxes, bobcats, black-tailed deer,
  rabbits, squirrels
• Western coasts of North and South America, areas
  around the Mediterranean Sea, South Africa, and
  Australia

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Temperate Grasslands

• Rich mix of grasses and under-laid by some of the
  worlds most fertile soils
• Include plains and prairies that have been
  converted into agricultural fields
• Periodic fires and heavy grazing by large
  herbivores
• Warm to hot summers, cold winters, moderate,
  seasonal precipitation, occasional fires
• Lush, perennial grasses and herbs, resistant to
  drought, fire, and cold
• Coyotes, wolves, grizzly bears, mule deer,
  pronghorn antelope, rabbits, prairie dogs
• Central Asia, North America, Australia, central
  Europe, upland plateaus of South America

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Desert

• Usually has an annual precipitation of less than
  25 centimeters
• Many undergo extreme temperature changes
  throughout the day
• Organisms in this biome can tolerate extreme
  conditions
• Cacti and other succulents
• Mountain lions, gray foxes, bobcats, reptiles
• Africa, Asia, the Middle East, US, Mexico, South
  America, and Australia

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Tropical Savanna

• Dominated with grasses with a few scattered trees
• Found in tropics of central South America, large
  parts of eastern Africa, southern Brazil, and
  northern Australia
• Warm temperatures, seasonal rainfall, compact
  soil, frequent fires set by lightning
• Tall perennial grasses, sometimes
  drought-tolerant and fire-resistant trees or
  shrubs
• Rich in herbivores and their predators
• Lions, cheetahs, leopards, hyenas
• Elephants, giraffes, antelopes, zebras, baboons,
  eagles

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Tropical Seasonal Forest (Tropical Dry Forests)

• Tropical Dry Forest distinct wet and dry
  seasons central West Africa, much of India, and
  Southeast Asia shed their leaves during the
  long, dry season and re-leaf only during the
  following heavy rains or monsoons
• Contain tall, deciduous trees that form a dense
  canopy during the wet season drought tolerant
  orchids
• Tigers, monkeys, elephants, Indian rhinoceros,
  spot-billed pelican

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Tropical Rain Forests

• Tropical Rain Forest found in very humid
  equatorial areas such as Indonesia and the Amazon
  River basin in South America rainfall is
  abundant and reduced rainfall lasts only a few
  months
• Most animals are tree-dwellers (monkeys, birds,
  insects, snakes, bats, and frogs)
• The soils are very poor because the high
  temperatures and rainfall lead to a rapid
  decomposition and recycling instead of a buildup
  of organic material
• Most nutrients are incorporated in the living
  organisms

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Other Land Areas

• Mountain Ranges-temperature becomes colder and
  precipitation increases from base to summit
• Polar ice caps-border the tundra are cold
  year-round plants and algae are few, but
  includes mosses and lichens
• Polar bears, seals, insects, and mites are the
  dominant animals
• In the south polar region, Antarctica is covered
  by a layer of ice nearly 5 km thick in some
  places penguins and marine mammals

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AQUATICECOSYSTEMS
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Freshwater Ecosystems

• Rivers and streams-water flows in one direction
  beginning at the headwater and traveling to the
  mouth
• May also start from underground springs or from
  snowmelt
• Sediment is material that is deposited by water,
  wind, or glaciers
• Lakes and ponds-inland body of standing water
• Oligotrophic lakes are nutrient poor and found
  high in the mountains
• Eutrophic lakes are nutrient rich and usually
  found at lower latitudes

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Zones of Lakes Ponds

• Littoral Zone-area closest to the shore, water is
  shallow and sunlight reaches the bottom aquatic
  plants and algae
• Limnetic Zone-open water area that is well lit
  and dominated by plankton
• Plankton are free-floating photosynthetic
  autotrophs that live in freshwater or marine
  ecosystems contains many species of fish in
  freshwater because of the availability of food,
  readily plankton

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Zones of Lakes Ponds

• Profundal Zone-the deepest areas of a large lake,
  which is much colder and lower in oxygen than the
  other two zones light is not abundant

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Transitional Aquatic Ecosystems

• Areas where land and water or saltwater and
  freshwater intermingle
• Wetlands-areas such as marshes, swamps, and bogs
  that are saturated with water and support aquatic
  plants
• Plant species include duckweed, pond lilies,
  cattails, sedges, mangroves, cypress, and willows
• Animal species include amphibians, reptiles,
  birds, and mammals

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Sedge and Sphagnum bogs of the Cape Breton
Plateau-Taiga
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Transitional Aquatic Ecosystems

• Estuaries-formed where freshwater from a river or
  stream merges with salt water from the ocean
• Are areas of transition from freshwater to
  saltwater and from land to sea inhabited by a
  wide variety of species
• Algae, seaweeds, and marsh grasses are the
  dominant producers
• Can find mangrove trees in tropical estuaries

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Marine Ecosystems
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Intertidal Zone

• Narrow band where the ocean meets land
• Organisms that live here must adapt to constant
  change as daily tides and waves alternately
  submerge and expose the shore
• Is further divided into vertical zones
• Spray zone (dry most of the time)
• High-tide zone (under water only during high
  tides)
• Mid-tide zone (undergoes severe disruption twice
  a day)
• Low-tide zone (covered with water unless tide is
  unusually low) is most populated area of the
  zones

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Open Ocean Ecosystems

• Photic called the euphotic zone sunlight is
  able to penetrate, surface seaweeds and plankton
  along with many species of fish, sea turtles,
  jellyfish, whales and dophins live here
• Aphotic light is unable to penetrate is part
  of the pelagic zone which is in constant darkness
  and generally cold

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Open Ocean Ecosystems

• Benthic Zone-area along the ocean floor that
  consists of sand, silt, and dead organisms
• Abyssal Zone-the deepest region of the ocean
  water in this area is very cold

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Benthic Zone

• Area along the ocean floor that consists of sand,
  silt, and dead organisms
• Species diversity increases with depth except
  where hydrothermal vents exists
• Organisms include shrimp, crab, tubeworms,
  octopuses, squid, and a variety of fishes

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Coastal Ocean

• Extends from the low-tide mark to the outer edge
  of the continental shelf
• Usually falls within the photic zone so
  photosynthesis can occur
• Rich in plankton and other organisms
• Contains the kelp forest, which is one of the
  most productive communities
• Kelp forest giant brown algae that can grow as
  much as 50 cm a day
• Huge forests of this seaweed are found in
  cold-temperature seas around the world
• Along the coast of CA and the Pacific NW
• Support a complex food web that includes snails,
  sea urchins, sea otters, and a variety of fishes,
  seals, and whales

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Coral Reefs

• Coral reefs are the most diverse ecosystems
• Characterized by corals
• Found in warm, shallow marine waters.
• Have a symbiotic relationship with algae known as
  zooxanthellae
• Are sensitive to changes in the environment

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