Biology Semester Review 2 12/10

Biology Semester Review 2 12/10

Energy flow in an Ecosystem

• Trophic levels

• steps in a food chain or web

Primary and Secondary Producers

• Autotrophs

• capture energy from sunlight or chemicals     to produce food or produce living tissue

Autotrophs

• chemotrophs- chemosynthesis (chemicals to food)

• Phototrophs-photosynthesis (sun light to food)

trophic level Consumers

• Heterotrophs

• rely on other organisms for its energy and food supply

Multiple Choice

A biomass pyramid of an ecosystem is shown.

• Organisms at higher trophic levels have less energy available to them than organisms at lower trophic levels.

• Organisms at higher trophic levels require smaller habitats than organisms at lower trophic levels.

• Organisms at lower trophic levels provide less energy than organisms at higher trophic levels.

• Organisms at lower trophic levels outcompete organisms at higher trophic levels.

Multiple Choice

Refer to the illustration above. Level “A” is composed of

• secondary consumers
• primary consumers
• producers
• predators

Carnivores

• obtains energy from eating another animal

Herbivore

obtains energy from eating only plants

Omnivore

obtains energy from eating both animals and plants

Detritivores

• obtains energy from eating the remains of plants and animals

Multiple Choice

Which role of protists has the most positive effect on maintaining the plant population in an ecosystem?

• Protists are a major food source for animals.

• Protists produce approximately 75 percent of the oxygen on Earth.

• Protists decompose dead materials, returning nutrients to the soil

• Protists found in the gut of animals assist in digestion.

Decomposers

obtains energy from dead organic matter

Multiple Choice

Saprophytes are fungi that feed on dead and decomposing organisms. They secrete enzymes that digest components of cell walls, such as cellulose and lignin. Which statement explains why these fungi are an important part of the biogeochemical cycle?

• Saprophytes perform gas exchange that assists the cellular activities of autotrophs.

• Saprophytes extract minerals from living tissue to recycle them back into the soil.

• Saprophytes transport nutrients through the xylem and phloem in autotrophs.

• Saprophytes return organic material to the soil for use by living organisms.

food chain

steps in ecosystem

transfer energy by eating or being eaten

Multiple Choice

According to the food web, which of these supply energy for all the other organisms?     

• snakes
• insects
• grasses
• cougars

Food Web

the complex feeding relationships that exist in an ecosystem

Multiple Choice

A pond ecosystem is shown in the diagram below. Which statement describes an interaction that helps maintain the dynamic equilibrium of this ecosystem?

• The frogs make energy available to this ecosystem through the process of photosynthesis.

• The algae directly provide food for both the rotifers and the catfish.

• The green-backed heron provides energy for the mosquito larvae.

• The catfish population helps control the populations of water boatman and waterfleas.

Multiple Choice

The amount of energy the producers in this energy pyramid provide the primary consumers is 54,000 joules. From this amount, 540 joules are provided to the tertiary consumers. Based on this model, how much of the energy was provided to secondary consumers?

• 53,460 J

• 5,400 J

• 540 J

• 54 J

Energy Pyramid

• Energy is lost through heat

• 10% rule

• only 10% of the energy is transferred to the next trophic level

Biomass Pyramid

• the total amount of living tissue within a given trophic level

Pyramid of Numbers

The number of individual organisms in each trophic level

Multiple Choice

Which correctly show the transfer of energy within an ecosystem?

• producer, decomposer, herbivore, omnivore
• canivore, herbivore, decomposer, omnivore
• omnivore, carnivore, herbivore, primary consumer
• producer, herbivore, carnivore, decomposer