Levels of Life’s Hierarchy (Levels of Organization)
Least specific
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Biosphere – All environments on earth that support life
(Basically, the Earth and the sky
above it that has living things occupying it.)
Biome – Major types of ecological associations that occupy broad geographic regions of land or
water and are characterized by organisms adapted to the particular environments
Ecosystem – all living organisms in a particular area as well as the nonliving, physical
components they interact with (ex. Sunlight, water, etc.)
Community – All living things in an area
Population – Single species living in a single area
Organism – Single individual
Organ System – group of organs working together for a certain function
Organ – 1 part of an organ system
Tissue – group of similar cells that do a particular function for an organ
Cell – Smallest unit of life (All living things are made of up one or more cells)
Organelle – “organ” of a cell
Molecule – cluster of atoms held together by chemical bonds
Atom - basic unit of matter made of dense nucleus (protons and neutrons) with electron cloud
around it
Most specific
Biomes
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Tropical Forest (rain forest and dry)
Temperature: warm to high
Rainfall: varied – heavy
Plants: thorny shrubs, deciduous trees, & succulents. (very diverse)
Sunlight: little reaches the forest floor.
Habitats: floor –> canopy.
o Poor soil, due to high temp & heavy rains (leaching).
Animals: monkeys, birds, snakes, bats, frogs – tree dwelling.
The Rain Forest contains about 45% of all animal species
2. Savanna
 Temperature: warm year round
o Rainfall: moderate rainfall (with long periods of drought) BIOME DEFINED MAINLY BY
THIS
 Plants: grasses & scattered trees.
o growing point below ground & resistance to periods of drought.
 Habitats: migratory
 Poor soil, lack of moisture, grazing animals, & fires inhibit most trees.
o Biome is dependent upon fires to keep nutrient rich enough to support life
 Animals: large grazing mammals, insects, burrowing animals, predators (lions & cheetahs).
3. Deserts
• Temperature: very hot,
and cold (Antarctica)
• Rainfall: dry
• Plants: none, deep rooted shrubs, succulents.
– waxy coating to prevent water loss
– many seeds that remain dormant until it rains
• Sunlight: extreme
• Habitats: burrows, active at night
• Animals: ants, birds, rodents, lizards, snakes, & hawks.
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Chaparral
Temperature: mild winter, hot summer
Rainfall: rain in winter, dry in summer
Plants: dense shrubs with tough evergreen leaves. Seasonal plants.
– Food reserves in roots allow for rapid growth after frequent fires.
– Seeds only germinate after hot fire.
Animals: deer, birds, rodents, lizards & snakes
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Temperate grasslands (Prairies)
Temperature: relatively cold
Rainfall: rain, but periodic severe droughts
Plants: grass, mostly treeless
o fire & grazing prevents tree growth
Habitats: bird nests on ground, burrows.
Animals: large grazing mammals (bison, wild horses).
Soil supports diverse microorganisms & small animals.
One of the most productive agricultural regions in the world
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Temperate (deciduous) Forest
Temperature: cold winter, hot summer
Rainfall: high precipitation
Plants: deciduous trees (oak, hickory, maple)
Habitats: rich soil, leaf litter, burrow
Animals: invertebrates, mice, shrew, squirrels, birds, bobcats, foxes, bears, & mountain lions.
Most destroyed by loggers & urban development.
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Taiga (Coniferous) ForestTemperature: long cold winters, short wet summers
Rainfall: considerable precipitation (snow)
Plants: cone bearing evergreens
– (spruce, pine, fur)
Habitats: soil thin & acidic
Animals: moose, elk, bears, wolves, hares, migratory birds.
Heavily logged.
Largest terrestrial biome
Tundra
Temperature: extremely cold
Rainfall: little
Plants: no trees, shrubs, grasses, mosses, and lichens.
– Permafrost prevents deep root penetration
Sunlight: little light for much of the winter, constant daylight in summer
Habitats: migratory (summer is a breeding ground), high altitude, permafrost, soil continually
saturated due to poor drainage and slow evaporation.
Animals: well insulated (oxen & caribou), lemmings, fox, snowy owl.
During the summer, clouds of mosquitoes fill the air due to the marshy ground.