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

Study the graph.

What is a limiting factor for steelhead trout?

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

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