Introduction to Ecology
Part III Biomes
What is a Biome?
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Are distinguished by the presence of
characteristic plants and animals
 Commonly identified by their dominant
plant life
 Biomes are distributed over the Earth based
on climate (temperature and precipitation)
and latitude
8 Major categories of Biomes
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Tundra
Tropical forest
Temperate forest
Taiga
Temperate grasslands
Savanna
Chaparral
Desert
Tundra

Description:
– Cold and largely treeless biome that forms a
continuous belt across N. America, Europe,
and Asia

Largest northernmost biome (covers 1/5 of
the world’s surface)
Tundra

Temperature:
– -26 OC to 12 OC

Precipitation:
– Less than 25 cm/year (9.9 inches)
Tundra

Soil:
– Most, thin topsoil over permafrost; low in
nutrients; slightly acidic
– Soil above permafrost remains frozen for all
but 8 weeks a year

Vegetation:
– Mosses, lichens, grasses, and dwarf woody
plants
Tundra
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Animals:
– Caribou, musk oxen, snowy owls, arctic
foxes, lemmings, and snowshoe hares
Tropical Forest

Near the equator (between 23.5ON and
23.5OS)

Includes parts of Asia, Africa, S. America,
and Central America
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Have two seasons (tropical rain and
tropical dry forests)
Tropical Forest
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Temperature:
– 6 OC to 14 OC
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***Most productive biome***
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Precipitation:
– 200 – 400 cm/year
Tropical Forest
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Soil:
– Moist, moderately thick topsoil, moderate
nutrients
Tropical Forest

Vegetation:
– Broad-leaved evergreen trees and shrubs
– Mostly made of trees 50 – 60 meters tall,
stretching its canopy shading the forest floor
 Creating a virtual plant free floor. WHY?
 Small plants live on the branches called
epiphytes (mosses, orchids, and
bromeliads)
Tropical Forest

Highest species richness:
– 300 different species of plants per hectare
– More than 1 million species of tree beetles
– Contains ½ of the world’s species
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Animals:
– Monkeys, snakes, lizards, parrots, insects,
etc..
Temperate Forest
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Occurs in N. America, western and
central Europe, and Northeastern Asia
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Has distinct seasons and moderate
climate
Temperate Forest
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Temperature:
– 6 OC to 25 OC
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Precipitation:
– 75 – 125 cm/year
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Soil:
– Moderately thick topsoil, moderate nutrient
level
Temperate Forest
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Vegetation:
– Broad-leaved deciduous trees (maple, oaks,
beech, willow, and birch)
– Shrubs (ferns, herbs, and mosses)
– Evergreen conifer trees (evergreen, spruce,
and other pines)
Temperate Forest
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Animals:
– Bears, wolves, white-tailed deer, foxes,
raccoons, and squirrels
Taiga
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Is south of the tundra and north of the
temperate regions
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Span across N. Europe, Asia, and N.
America; just below the arctic circle
Taiga
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Temperature:
– Long winters, short summers
– -10 OC to 14 OC
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Precipitation:
– 35 – 75 cm/year
Taiga
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Soil:
– Low nutrients, highly acidic
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Vegetation:
– Coniferous evergreen trees (spruce, firs, and
pines)
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Animals:
– Moose, bears, wolves, lynx, and hares
Temperate grasslands
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Covers a large area of N. America, Asia,
Europe, Australia, and S. America
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Forms interior of the continents
Temperate grasslands
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Temperature:
– 0 OC to 25 OC
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Precipitation:
– 25 – 75 cm/year
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Soil:
– Deep layer of topsoil; very rich in nutrients
Temperate grasslands
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Vegetation:
–
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Very few trees
Dense, tall grasses, in most areas
Short grasses in drier areas
Mainly farming and grazing areas
Animals:
– Bison, buffalo, and horses
Savanna
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Parts of Africa, W. India, N. Australia, and
some S. America
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Located in tropical and subtropical areas
near the equator and between tropical
forest and desert biome
Savanna
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Temperature:
– 16 OC to 34 OC
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Precipitation:
– 75 – 150 cm/year
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Soil:
– Dry, thin topsoil
– Porous and low in nutrients
Savanna
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Vegetation:
– Tall grasses with horizontal roots
– Scattered Trees:
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Often leaves that are sharp and thorny
Animals:
– Elephants, black/white rhinos, giraffes, and
zebras
Chaparral
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Primarily located on coastal areas with
Mediterranean climates
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California (“HOLLYWOOD” sign)
Chaparral
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Temperature:
– 10 OC to 18 OC
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Precipitation:
– Less than 25 cm/year (9.9 inches)
– Warm dry summers, and mild wet winters
Chaparral
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Soil:
– Rocky, thin topsoil
– Low in nutrients
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Vegetation:
– Evergreen shrubs, and small trees
Chamise, scrub oaks, olive trees, herbs
(sage and bay)
 Leaves small and leathery with lots of oils
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Chaparral
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Animals:
– Quail, Lizard, chipmunks, and mule deer
Desert
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Temperature:
– 7 OC to 38 OC
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Precipitation:
– Less than 25 cm/year (9.9 inches)
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Soil:
– Dry, often sandy, low in nutrients
Desert
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Vegetation:
– Little to no vegetation
– Succulent plants and scattered grasses

Cactus – can drop water levels below 50 –
75% (fatal for other plants)
Desert
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Animals:
– Reptiles – (Gila monster), rattle snakes
– Amphibians – spadefoot toad; burrows
underground
– Elf owl (burrow into cactus), desert insects and
spiders (nocturnal)
Aquatic Ecosystems
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Ecosystem of Fresh and Salt water
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Major Oceans:
– Average of 2.3 – 6.8 miles deep
– Atlantic and Pacific Oceans
Aquatic Ecosystems
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Estuaries:
– Where fresh water from a river mixes with
salt water from the ocean
– Estuaries include Chesapeake Bay (largest
estuary in the U.S.), mud flats, mangrove
swamps, and salt marshes
Aquatic Ecosystems
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Rivers and streams:
– Originate from snow melt (starting as
streams)
– Cold and full of oxygen that run toward a
mouth to become wider and deeper forming a
river
– Example: Mississippi river
Aquatic Ecosystems
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Freshwater wetlands:
– Areas of land that are covered with
freshwater for at least part of each year
– Swamps – dominated by woody plants (trees
and shrubs)
– Marshes – non-woody plants (cattails)
– Most important wetland in the world is the
Florida Everglades