Chapter 2 - Ecosystems and Biomes
I Energy Flow in Ecosystems
A. Energy Roles
1. producers - organisms that can make their own food using photosynthesis
2. consumers - organisms that obtain energy by eating other organisms
a. herbivores - eat only plants
ex. deer, rabbits, grasshopper
b. carnivores - eat only animals
ex. lion, owl, spider, alligator, frog
c. omnivores - eat both plants & animals
ex. bears, crows, humans, rats
d. scavengers - carnivores that eat dead
animals they did not kill themselves
ex. vultures, hyenas, catfish
3. decomposers - organisms that break down wastes and dead organisms
and return these nutrients to the soil
ex. bacteria and fungi
B. Food Chain - series of events in which one
organism eats another and gets energy
C. Food Web - many overlapping food chains in an ecosystem
D. Energy Pyramid - diagram that shows the amount of energy that
moves from one feeding level to another
II Cycles of Nature
A. The Water Cycle - continuous process
by which water moves from the surface
to the atmosphere and back
1. evaporation - liquid water changes to a gas (or vapor)
a. uses energy from the sun
b. transpiration - water evaporating from plants
2. condensation - water vapor turns back into a liquid
a. vapor cools off and sticks together
b. this forms clouds, fog and dew
3. precipitation - rain, snow, sleet or hail
4. surface runoff - flows into bodies of water (streams, lakes, oceans)
5. infiltration-surface water soaks into the ground (forming groundwater)
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B. Carbon and Oxygen Cycles
1. producers
a. take in carbon dioxide gas
b. release oxygen gas
2. consumers
a. take in oxygen gas
b. release carbon dioxide gas
C. The Nitrogen Cycle
1. air is 78% nitrogen gas (oxygen is 20%)
2. nitrogen fixation - combining nitrogen with other elements
a. done by bacteria
b. nitrogen compounds taken in by plants and then animals
3. bacteria break down waste and dead organisms to release nitrogen back
into the air
III Biogeography
A. Definition – the study of where organisms live
B. Factors Affecting Biogeography
1. continental drift
2. means of dispersal (movement)
a. wind and water
b. carried by other living things
c. swim, walk, fly on their own
3. physical barriers
a. water
b. mountains
c. deserts
4. competition
5. climate - typical weather pattern in
an area over a long period of time
IV Biomes
A. Definition - a group of land ecosystems
with similar climates and organisms
B. Six Different Biomes
Biome Characteristics Plants Animals
Tropical
Rain 200-300 cm of thousands millions
Forest rain/yr
Desert less than 25 cm cactus reptiles
of rain insects
Grassland 25 - 75 cm grasses herbivores
of rain only carnivores
(irregular)
Deciduous trees shed oaks birds, deer
Forest their leaves maples fox, skunk
each yr.
Boreal coniferous trees pine, fir moose
Forest (cones & needles) spruce wolf, bear
Tundra cold and dry mosses caribou
permafrost grasses white fur
(soil is frozen all blubber
year below surface)