Chapter 3: Ecosystems
I. How Ecosystems Change
A. Ecological succession
1. normal gradual changes that occur in types of
species that live in an area
2. 2 types of factors that are responsible for
limiting life in a particular area are
precipitation & temperature
B. Types of succession:
1. Primary succession:
a) takes place where there were no plants
before
b) example: after a volcano erupts and
destroys everything in its path
c) steps in succession
1. pioneer species (lichens) arrive
2. new soil forms as the lichens, weather
and erosion break down the rocks
3. mosses and ferns start to grow
4. soil thickens as the ferns die
5. wildflowers & other plants take over
6. shrubs and trees begin to grow
7. mammals, birds, and insects move in
2. Secondary succession
a) occurs after a fire, buildings torn down,
land has been flooded, or in abandoned
logging areas
b) succession takes place more quickly, since
there is already soil there
3. Climax community
a) a community that is stable and reached
the end of succession
b) example: maple forest
II. Biomes
A. Factors that affect biomes
1. temperature
2. precipitation
B. Major Biomes
1. large areas with similar climates are biomes
2. TUNDRA
a) just south of North Pole
b) cold, dry, treeless
c) winters: 6-9 months long & sun barely
rises
d) permafrost: permanently frozen soil
e) types of animals: reindeer, arctic hares,
snowy owls, geese, caribou
f) types of plants: lichens, mosses
3. TAIGA
a) south of tundra
b) cold forest region
c) wetted and warmed than tundra
d) more snow; shorter winter
e) animals: moose, bears, lynx, foxes
f) plants: cone-bearing evergreens
4. TEMPERATE DECIDUOUS FOREST
a) has 4 seasons a year
b) 75-150cm precipitation throughout year
c) plants: trees that lose their leaves every
autumn
d) Cincinnati is in this biome
e) located in same latitude as desert
5. TEMPERATE RAIN FOREST
a) receives 200-400cm rain/year
b) located in the Pacific Northwest
c) animals: black bear, bobcat, cougar
d) plants: spruce, cedar, firs that grow high
6. TROPICAL RAIN FOREST
a) average temperature: 77 degrees
b) located around equator
c) greatest variety of organisms on Earth
d) rain forest has 4 zones (emergents,
canopy, understory, & forest floor)
e) animals: macaw, jaguar, insects
f) plants: rare orchids, plants that may help
cure diseases
g) human impact: cutting down and
destroying rainforest
7. DESERT
a) driest biome
b) less than 25cm rain/year
c) soil is gravelly or sandy
d) plants: cactus
e) animals: scorpions, snakes, reptiles,
kangaroo rats
8. GRASSLANDS
a) temperate and tropical regions with more
rain than desert
b) have a dry season
c) located in Great Plains
d) plants: grasses
e) animals: grazing animals like cattle or
sheep
III. Aquatic Ecosystems
A. Freshwater
1. rivers and streams
a) flowing freshwater
b) nutrients come from the land around the
water
c) types of organisms: mussels, minnows,
leeches, fish
2. lakes and ponds
a) water that hardly ever moves
b) plant growth is limited to shoreline
c) lakes: larger/deeper
d) ponds: smaller/shallower
e) organisms: algae, cattails, and fish
3. wetlands
a) also called bogs, swamps
b) regions that are wet for most of the year
c) animals: beavers, alligators, muskrat
d) Example: Everglades
B. Saltwater Ecosystems
1. open oceans
a) upper 600 feet: light zone with lots of
plankton; base of food chain in open ocean
b) below 600 feet: dark zone
2. coral reefs
a) formed from calcium carbonate shells
secreted by coral animals
b) contain a great diversity of organisms
c) Example: Great Barrier Reef
d) Coral reefs are very fragile
3. seashores
a)intertidal zone: portion of the shoreline
exposed during low tide
b) organisms must adapt to great changes in
their environment
c) organisms: sea stars, seaweed
4. estuaries
a) area where fresh and salt water mix
b) example: bays, lagoons, inlets
c) high nutrient content
d) estuaries act as nurseries for ocean fish
e) organisms: shrimp, clams, oysters, and
fish