Notes:
Chapter 26
Ecosystems/Biomes
Section 26 -1: How Ecosystems Change
A. Ecological succession: normal, gradual changes that occur in the
types of species that live in an area
1. Primary succession: begins in a place without soil.
a. Starts with pioneer species such as lichens, that can grow on rock
b. New soil forms as weather and erosion break down rock.
c. Decaying plants add organic material to new soil.
2. Secondary succession: begins in a place that has soil and once had living organisms
a. Example: after a fire or removal of buildings
b. Occurs faster and has different pioneer species than primary succession
B. Climax community: stable stage of ecological diversity and balance
What is going on in the picture above with regard to succession?
Was this due to primary succession or secondary succession?
26-2
Earth and Latitude



Biomes are influenced
by latitude and
altitude.
As you move from the
equator you see other
biomes.
As you go up a
mountain range
temperature decreases
also influencing the
type of biome that
may exist.
Biome Influenced by Altitude: Mountain Range
A. Biome: Large geographic areas that have similar climates and ecosystems.
More about Biomes (6 Types):
1. Tundra: Cold, dry treeless region sometimes called a cold desert (winters are six to
nine months long).
Animals: Polar bears, seals, penguins and arctic fox
Vegetation: moss and lichens
Climate: Long winters, short summers, can have 24 hours of darkness and sunlight
Location: Near the poles and at higher elevations
2. Taiga: a cold region of cone bearing evergreen trees, including pines, firs hemlocks,
spruces and cedars.
Animals: moose, elk, wolves, grizzly/brown/Kodiak Bears and squirrels
Vegetation: pines, firs, cedars (little to no grass, trees blockout sunlight)
Climate: shorter winters than tundra, lots of snow
Location: higher than mid latitude, and higher than sea level.
Ex. State of Maine, Alaska
3. Temperate Deciduous Forest: contain four distinct seasons and are dominated by deciduous
trees, which lose their leaves every autumn.
Animals: deer, black bear, squirrels, chipmunks and rabbits
Vegetation: maple, oaks (deciduous trees =lose leaves in fall), pines, grass
Climate: consistent amount of precipitation throughout the year, four seasons
Location: usually at sea level and found at mid latitude and at the base of mountain
sides. Ex. Most of the North Eastern United States
4. Tropical Rain Forest: annual rainfall is roughly 200 –225 cm per year, which allows for lush
green plant growth.
Animals: monkeys, tree frogs, snakes, piranha, gorillas and toucans
Vegetation: lush: contains ferns and interlocking trees
Climate: very humid and lots of rainfall
Location: found near the equator./
Ex. Amazon (largest tropical rain forest)
5. Grasslands: region/area dominated by grasses that receive 25 –75 cm of rain each year.
Animals: lions, antelope, zebra, water buffalo, cheetah and hyenas
Vegetation: flat, grass very few trees
Climate: warm, little rain; enough to keep grass but not enough for trees
Location: largely inland at the base of mountain ranges
Ex. Central Africa and the Central United States
6. Desert: the driest biome on Earth receives less than 25cm of rainfall per year and has very
few plants.
Animals: lizards, rattle snakes, vultures, camels, scorpions
Vegetation: cactus and some small shrubs
Climate: dry, extremely hot during the day and very cold nights
Location: just above & below the equator and base of mountains
Ex. Parts of Nevada and Arizona
Section 3 Aquatic Ecosystems:
A. Freshwater ecosystems: include flowing and standing water, low or no salt
 Water pollution: a problem caused by fertilizer-filled runoff and sewage
1. Wetlands: regions wet all or most of year
 Lie between solid land and water
 Very fertile ecosystems
B. Salt water ecosystems: 95% of Earth’s water contains high concentration of salt, or high
salinity.
1. Coral reefs: diverse and fragile ecosystems formed from coral shells of calcium
carbonate
2. Seashores: along coastlines
a. Intertidal zone: covered with water at high tide and exposed to air at low tide
 Drastic changes in temperature, moisture, salinity, and wave action
3. Estuaries: where a river meets an ocean; called bays, lagoons, harbors, inlets, sounds
 Rich in nutrients
 Changing mixture of salt water and freshwater