Review for Ecology Summative 2

One biotic factor that affects consumers in an ocean ecosystem is

• number of autotrophs

• temperature variation

• salt content

• pH of water

Which population in this food web would most likely be negatively affected by an increase in the mouse population?

• snake

• rabbit

• wolf

• hawk

Decomposers are important in the environment because they:

• convert large molecules into simpler molecules that can then be recycled

• release heat from large molecules so that the heat can be recycled through the ecosystem

• can take in carbon dioxide and convert it into oxygen

• convert molecules of living organisms into permanent biotic parts of an ecosystem

A new island formed by volcanic action may eventually become populated with biotic communities as a result of:

• a decrease in the amount of organic material present

• decreased levels of carbon dioxide in the area

• the lack of abiotic factors in the area

• the process of ecological succession

One biotic factor that limits the carrying capacity of any habitat is the

• availability of water

• level of atmospheric oxygen

• activity of decomposers

• amount of soil erosion

The role of decomposers in a food web is to:

• break down dead organisms and recycle nutrients

• produce energy for the ecosystem

• compete with primary consumers for food

• act as primary producers

Which organisms are correctly paired with their nutritional roles, or what type of consumer the organism is?

• Hawk is a decomposer; insect-eating bird is a parasite

• Mouse is an autotroph; flower seed is a heterotroph

• mountain lion is a predator; bark beetle is a herbivore

• grasshopper is a carnivore; grass is an autotroph

An established ecosystem may remain stable over hundreds of years because

• species interdependence is absent

• there is a lack of variety in the species

• no competition exists between the species

• there are natural checks on species that create ecosystem equilibrium

An energy pyramid is represented below. The energy for use by organisms in level A originally comes from

• producers

• the Sun

• primary consumers

• apex predators

The size of a mouse population in a natural ecosystem tends to remain relatively constant due to

• the carrying capacity of the environment

• the lack of natural predators

• cycling of energy

• increased numbers of decomposers