The earth is an open system with respect to

1. organisms

2. chemicals

3. energy 

4. all of the above

Plants capture approximately __________________ of the sun's energy while other trophics levels capture about _________________ of the energy available to them in their food.

1. 1%, 10%

2. 10%, 60%

3. 10%, 1%

4. 60%, 10%

Which trophic level is incorrectly defined?
1. Carnivores- secondary or tertiary consumer
2. Decomposer- microbial heterotrophs
3. Herbivores - primary consumer
4. Omnivores - Molds, yeast and mushrooms

What percent of energy in the sunlight availble to the primary producers is converted by them into net primary productivity ?
1. 1
2. 2
3. 5
4. 10 

The second trophic level in a lake is:

1. Phytoplankton

2. Zooplankton

3. Benthos

4. Fishes

Most food chains are composed of 

1. 1 or 2 species

2. 3 or 4 species

3. 9 or 10 species

4. More than 16 species

Most primary productivity in the surface water of lakes and oceans is by:
1. Floating plants
2. Red and brown algae
3. Zooplankton
4. Phytoplankton

Th primary producers of the deep-sea hydrothermal vent ecosystem are

(1) green algae

(2) chemosynthetic bacteria

(3) blue-green algae

(4) coral reefs

Identify the possible link A in the following food chain

Green plant -> Insect -> Frog -> A -> Eagle

1. rabbit                         

2. wolf

3. cobra                         

4. parrot

Mass of living matter at a trophic level in an area at any time is called 

1. Detritus

2. Humus

3. Standing state 

4. Standing crop