Communities

1
Communities Biomes

• What determines what lives in a specific area?

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Limiting factors

• Def any environmental factor (whether abiotic
  or biotic) that restricts the existence, numbers,
  reproduction, or distribution of organisms in an
  ecosystem.
• (Ex. Amount of food, predators, temperature)
• Factors that limit one population may also have
  an indirect effect on another population.

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Biomes

• A large group of ecosystems that share the same
  type of climax community

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Types of biomes

• Aquatic 1. marine biomes (saltwater)
• 2. freshwater biomes
• Terrestrial 3. tundra
• 4. taiga (coniferous forest)
• 5. desert
• 6. grassland
• 7. temperate forest (deciduous forest)
• 8. tropical rain forest

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Marine Biomes

• Oceans contain the largest amount of living
  material (biomass) of all of the biomes but
  most of them are microscopic orgs!!!

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Freshwater Biomes

• EX. Lakes, ponds, rivers, streams
• Light penetration affects productivity
• (amount of life present)
• But, bottoms of lakes and ponds have decay taking
  place (dead orgs drift to bottom, bacteria break
  them down and form detritus),

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Figure 50.24 The distribution of major
terrestrial biomes
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Figure 20.25h Tundra
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Tundra

• Abiotic factors strong windslow precipshort
  and soggy summers long, cold, dark winters
  poorly developed soils, permafrost
• Dominant Plants mosses, lichens, sedges, short
  grasses (ground-hugging)
• Dominant wildlife birds and mammals that can
  withstand harshness migratory waterfowl, shore
  birds, musk ox, Arctic fox, caribou small
  rodents
• Geographic distribution northern N.A., Asia and
  Europe

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Tundra

• One of two biomes that circle poles, closest one
  to poles
• Treeless land
• Long summer days, short periods of winter
  sunlight
• Permafrost present permanently frozen ground
  under the topsoil
• When melts, ground is soggy and wet
• Cycle of freezing and thawing rips and crushes
  plant roots, so plants are small and stunted
• Also, process of decay is slow cold temps slow
  down bacteria, so not much humus (little
  nutrients in soil) again, plants are short and
  stunted
• Short growing season
• Low precipitation

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Figure 20.25g Coniferous forests
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Taiga/Boreal/Coniferous Forests

• Abiotic factors long, cold winters short, mild
  summers moderate precip high humidity acidic,
  nutrient-poor soil
• Dominant Plants needleleaf coniferous trees,
  broadleaf deciduous trees small, berry-bearing
  shrubs
• Dominant Wildlife predators like lynx and
  timberwolves weasel family herbivorous mammals
  (large and small) beavers migratory songbirds
• Geographic distribution N.A., Asia, Northern
  Europe

13
Tiaga, Boreal or Coniferous Forest

• Also circles poles
• Dense evergreen forests of conifers
• A little warmer and wetter than tundra, but long,
  severe winters and short,mild summers
• NO PERMAFROST layer, but decay of evergreen
  needles makes soil acidic and mineral-poor

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Figure 50.25c Deserts
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Deserts

• Abiotic factors low precip, variable temps, soil
  rich in minerals BUT poor in organic material
• Dominant plants cacti and succulents, creosote
  bush, plants with short life cycles
• Dominant wildlife predators (mtn lions, fox,
  bobcats) herbivores (deer, antelope, sheep,
  rats) bats, birds, insects, reptiles
• Geographic distribution Africa, Asia, Middle
  East, U.S., Mexico, S.A., Australia

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Deserts

• Driest of all biomes -- lt 25 cm rainfall per
  year but, other than this, deserts vary greatly
  
• Little to no plant life what is present is
  adapted for holding on in shifting sand and with
  little water available
• (what kinds of adaptations might the plants in
  a desert have?)
• Rodents are present, but these small herbivores
  stay hidden in day, come out at night nocturnal
• Carnivores coyotes, hawks, owls, scorpions,
  lizards

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Figure 50.25b Savanna
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Figure 50.25bx Savanna
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Grasslands/Savannah

• Abiotic factors warm temps, seasonal rainfall,
  compact soil, frequent fires due to lightning
• Dominant plants tall, perennial grasses,
  drought- and fire-resistant shrubs and trees
• Dominant wildlife predators (lions, leopards,
  cheetahs, hyenas, jackals), herbivores
  (elephants, giraffes, antelopes, zebras), birds
  (eagles, ostriches, weaver birds, storks),
  insects (termites)
• Geographic distribution large parts of eastern
  Africa, southern Brazil, northern Australia

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Figure 50.25e Temperate grassland
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Grasslands

• Abiotic factors warm to hot summers, cold
  winters, moderate, seasonal prec, fertile soils,
  fires
• Dominant plants lush, perennial grasses and
  herbs, resistant to drought, fire and
• Dominant wildlife predators (coyotes, badgers,
  wolves, grizzly bear) herbivores (deer,
  antelope, rabbits, prairie dogs, bison) birds
  (hawks, owls, bobwhite), insects (ants and
  grasshoppers)
• Geographic distribution central Asia, N.A.,
  Australia, central Europe, upland plateaus of
  S.A.

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Grasslands

• Between 25 and 75 cm of annual prec
• Covered with duh! grasses
• Other names prairies, steppes, savannas, pampas
• Fewer than 10-15 trees per hectare
• Occupies more area than any other terrestrial
  biome
• Good humus content in soil

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Figure 20.25f Temperate deciduous forest
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Temperate/Deciduous forest

• Abiotic factors cold to moderate winters, warm
  summers, year-round precip, fertils soil
• Dominant plants broadleaf deciduous trees, some
  conifers, flowering shrubs, herbs, mosses and
  ferns
• Dominant wildlife deer, black bears, bobcats,
  nut and acorn feeders, omnivores (raccoons and
  skunks), songbirds, turkeys Geographic
  distribution eastern U.S., southeastern Canada,
  most of Europe, parts of Japan, China, and
  Australia

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Temperate/Deciduous Forests

• 70-150 cm annual precip
• Broad-leaved hardwood trees that shed their
  leaves each year
• Soil has top layer that is rich in humus, deeper
  layer of clay. If minerals are not taken up by
  plants roots, the minerals get into clay and are
  trapped
• Many animals live here year round

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Figure 50.25a Tropical forests
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Tropical Rain Forests

• Abiotic factors hot and wet year-round, thin,
  nutrient-poor soil
• Dominant plants broad-leaved evergreen trees,
  ferns, large woody vines, climbing plants,
  orchids and bromeliads
• Dominant wildlife herbivores (sloths, tapirs),
  predators (jaguars), monkeys, birds (parrots,
  toucans), insects (butterflies, ants, beetles),
  piranhas and other freshwater fishes, reptiles
  (snakes0
• Geographic distribution parts of South and
  Central America, Southeast Asia, parts of Africa,
  southern India, northeastern Australia

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Tropical Rain Forests

• Home to more species than any other biome on
  earth (lots of different habitat possibilities)
• Warm temps, wet weather, lush vegetation
• Near equator
• Nutrients are tied up in living material very
  few nutrients are held in the soil because
  decomposers break down dead stuff very quickly