communities, biomes & ecosystems launch lab: what is my biological address? pg. 59 postal...
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Communities, Biomes & Ecosystems
• Launch Lab: What is my biological address?
pg. 59
• Postal address: Biological address;– Maria Lonnett Burgess Maria Lonnett Burgess– Manchester-by-the-Sea Community– MA Ecosystem– United States Biome– Plant Earth Biosphere
Communities, Biomes & Ecosystems
• All living org are limited by factors in the environment.
• Community: group interacting pop occupying same area at same time– plants, animals, bacteria,
fungi, etc.
• Limiting factor: biotic or abiotic factor that restricts numbers, repro or distribution of org
Note: Populations of org live w/in a relatively small area around oasis.
Tolerance
• Tolerance– Ability of any org to
survive when subjected to abiotic or biotic factors
• Upper and lower limits that define conditions in which org can survive
Ecological Succession
• Ecological succession
• Primary succession
• Pioneer community
•Community change where new populations of organism gradually replace existing ones
•Usually natural event: earthquake, volcano, flood, etc.
•Competition for food, shelter, light; some populations die or move on
•Succession begins very slowly where there is no existing community
•First group of organisms to occupy an area undergoing primary succession – help form soil
Henry Chandler Cowles ~ refined theory of ecological succession in 1898
Primary Succession
• Primary succession
– Establishing community in exposed rock, sand, water;
– Where no other community yet exists
Secondary Succession
• Secondary succession– Orderly &
predictable change after community of org is removed, but soil is intact (has been destroyed, etc.) Secondary succession: trees are colonizing
uncultivated fields and meadows.
Succession Endpoint?
• Cannot predict endpoint
• Climax community– Stable, mature community
with little change in number of species
• communities constantly changing at different rates
• Can’t determine if succession reached climax community anywhere on Earth!
“Swine Time” Climax Community
Ecological Climax Community
Quiz
1 How is temperature a limiting factor for polar bears?
2 How do ranges of tolerance affect the distribution of a species?
3 Classify the stage/s of succession of a field that is becoming overgrown with shrubs after a few years of disuse.
Quiz1 How is temperature a limiting factor for polar
bears?Temp defines a polar bear’s community and ecosystem. Its food sources and physiology are adapted to cold temps.
2 How do ranges of tolerance affect the distribution of a species?Fewer org in range of intolerance than in tolerance zone.
3 Classify the stages of succession of a field that is becoming overgrown with shrubs afer a few years of disuse.Secondary succession, b/c pioneer communities already established for shrubs to grow
Terrestrial Biomes
• Ecosystems on land are grouped into biomes, based on plant communities within them.
• Difference between weather & climate?• Weather - atmospheric condition at specific place &
time• Climate - avg weather conditions in area, incl temp
and precipitation (ppt)
• Look at fig 3.6, pg. 66
• Note how temp & ppt influence kind of vegetation that exists in an area (biome)
In class
Terrestrial Biomes
• Latitude– Distance of any point on
Earth N or S from equator
• 0o at equator, 90o at poles– Directness of sunlight
(radiation)– Earth’s surface heated
differently in zones:• polar• temperate• tropical
• What is a climatogram?
• How to create a climatogram.
Cimatogram
Major Land Biomes~classified by plants, temp, ppt and animals
• Tundra – youngest biome (10,000
yrs old)
• Treeless, layer of permanently frozen soil (permafrost)
• Cycle of freeze-thaw
• Temperate forest– Broad-leaved,
deciduous trees– Cold winters– Warm spring w/ ppt– Hot summers
• SE Canada, E US, Europe, Asia, Australia
• Temperate woodland and shrubland– Dominated by shrubs,
“chaparral” (in CA)– Less rainfall than temp
forest; cool, moist Fall, winter, spring-
– West coast N & S Americas, Mediterranean Sea, S Africa, Austrailia
– Frequent intense fires
• Temperate grassland• Fires, grazing animals,
drought prevent it from becoming forest– Fertile soils– Thick grasses
• Perennials
– N & S America• Praries
– Asia• Steppes
– Africa• Savannah, velds
– Australia• rangelands
• Desert– All continents except
Europe
• Annual evap rate exceeds precipitation rate
• Variety of plants & animals
• Tropical savanna– Grasses, scattered
trees– Less ppt – Africa, S America,
Australia– Hot rainy summers;
cool dry winters
• Tropical seasonal forest– Also called “tropical
dry forests”– Africa, Asia,
Australia, S & central America
– Similar to temperate deciduous forest
– Rainfall is seasonal
• Tropical rain forest– Most diverse of all
biomes– Humid all year; hot and
wet– S America, S Asia, W
Africa NE Australia– Tall trees, heavy
mosses, orchids make ‘canopy”
– Short trees, shrubs, ferns make “understory”
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