Communities, Biomes & Ecosystems
• Launch Lab: What is my biological address?
pg. 59
• Postal address:
–
–
–
–
–
Maria Lonnett Burgess
Manchester-by-the-Sea
MA
United States
Plant Earth
Biological address;
Maria Lonnett Burgess
Community
Ecosystem
Biome
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
Study the graph.
What is a limiting factor for steelhead trout?
Ecological Succession
• Ecological succession
Henry
Chandler
Cowles ~
refined theory
of ecological
succession in
1898
•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
• Primary succession
•Succession begins very slowly
where there is no existing community
• Pioneer community
•First group of organisms to occupy
an area undergoing primary
succession – help form soil
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
“Swine Time” Climax
Community
• communities constantly changing at
different rates
• Can’t determine if succession
reached climax community
anywhere on Earth!
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.
Quiz
1
2
3
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.
How do ranges of tolerance affect the
distribution of a species?
Fewer org in range of intolerance than in
tolerance zone.
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)
In class
• Look at fig 3.6, pg. 66
• Note how temp & ppt influence kind of
vegetation that exists in an area (biome)
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
Cimatogram
• What is a climatogram?
• How to create a climatogram.
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
Tundra plants and animals
• Boreal forest
– Northern coniferous
forest, or tiaga
– S of tundra
– Evergreen
• No permafrost layer
Boreal forest plants and animals
• Temperate forest
– Broad-leaved,
deciduous trees
– Cold winters
– Warm spring w/ ppt
– Hot summers
• SE Canada, E US,
Europe, Asia,
Australia
Temperate forest plants and animals
• 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
Wood & shrubland plants and animals
• 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
Grassland plants and animals
• Desert
– All continents except
Europe
• Annual evap rate
exceeds precipitation
rate
• Variety of plants &
animals
Desert plants and 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”
Other terrestrial areas
• Mountains
• Polar regions