14.9.3 Productivity Pyramids: Visualizing Energy Flows Flashcards Preview

AP Biology > 14.9.3 Productivity Pyramids: Visualizing Energy Flows > Flashcards

Flashcards in 14.9.3 Productivity Pyramids: Visualizing Energy Flows Deck (9)
Loading flashcards...
1
Q

Productivity Pyramids: Visualizing Energy Flows

A
  • Ecosystems can be analyzed on the basis of primary productivity-to-area ratios and total productivity.
  • The open ocean has the greatest total productivity. The rain forests have the highest productivity-to-area ratio.
  • The energy and biomass pyramids of different ecosystems have different appearances.
  • Deciduous forests have a large proportion of biomass tied up in primary producers.
2
Q

Question: Where do you think the highest rates of

photosynthesis occur on our planet?

A
  • Review: A biome is a major ecological community type, such as desert or tropical rain forest.
  • Comparing productivity across seven biomes yields
    interesting results. The open oceanaccounts for an estimated 65% of the earth’s surface (see yellow graph) and contains photosynthetic algae and other primary producers. The ocean, however, accounts for a relatively small proportion of the earth’s productivity. Tropical rain forests comprise less than 0.5% of the earth’s surface, yet they account for much of the earth’s productivity. The rain forests are home to nearly half of the earth’s biological species, many of which are primary producers.
3
Q

note

A
  • Review: A food chain portrays a feeding sequence from producers to consumers. A biome is a geographical region characterized by a distinctive landscape and community.
  • Different biomes have different food chains, depending on the predominant vegetation and organisms of the region. Coniferous trees characterize taiga, the largest terrestrial biome. Herbivores such as deer and moose feed on vegetation. Carnivores such as lynxes prey on herbivores
  • One way to look for patterns and distinctions between
    different food chains is to organize them by “stacking” the trophic levels on top of each other. Because primary
    producers form the base of the food chain, they are placed at the foundation (bottom) of the stack. Organizing trophic levels in this manner provides information about the efficiency of energy transfer through trophic levels.
  • Biomass is the aggregate dry weight of all organisms in a community or ecosystem. In the graphic on the left, the biomass present in each trophic level is represented. Many food chains that are organized in this manner look like a pyramid. Note that primary producers (the dark green area) account for the greatest proportion of biomass present. Energy transfer along trophic levels is, on average, 10% efficient. This rate of efficiency means that only 10% of the energy available in a given trophic level is transferred to the next trophic level.
4
Q

note 2

A
  • The graphic on the left compares a food pyramid of grassland versus forest biome. Primary producers in grasslands are mainly herbaceous grasses. In the forest, primary producers are mainly hardwood trees. Because much of the biomass of trees is in the form of wood, little of it is available to primary consumers. Energy in the animal tissues of herbivores (primary consumers) is more efficiently assimilated. Consequently, the transfer of energy from primary to secondary consumers is more efficient.
  • A food pyramid of an ocean food chain appears very different from terrestrial food chains. In the illustration to the left, the biomass of the primary producers appears to be less than that of the primary consumers. There is a greater biomass of primary producers, but because turnover rate is so high, the biomass of the primary producers is represented as a smaller section.
5
Q

Which of the following ecosystems has the lowest primary productivity per unit area?

A
  • open ocean
6
Q

Which of the following types of organisms occupies a trophic level with the least biomass?

A
  • tertiary consumers
7
Q

Which of the following would be found at the top of a typical productivity pyramid?

A
  • the trophic level with the smallest biomass
8
Q

True or false?

The pyramid of energy shows an increasing amount of energy available at each successive trophic level.

A
  • false
9
Q

A pyramid of biomass is

A
  • a measure of the total dry weight of the organisms in each trophic level.

Decks in AP Biology Class (383):