Exam 38: Communities and Ecosystems

You are shown an example of two organisms in a relationship,in which one lives on the other.The one organism living on the other benefits from nutritional resources,while the organism being lived upon is harmed.This is an example of

Natural selection requires that a trait in a species is genetic,which is heritable within the population,and has variable forms of the trait that increase survival or confer reproductive advantages.Consider that there is variation in beak lengths of a bird that eats nectar from flowers,and the heritable longer beak length allows feeding from larger flowers of a plant species with more tubular petal arrangements.The birds having longer beaks are more prevalent,and their longer beaks make successful reproduction more common for the plants with larger,tubular flowers,because of increased pollination success.What ecological process has happened between these two species?

The interaction between panic grass and its endophyte fungus that allow them to grow at 65°C together,but not independently is an example of

Energy is constantly being recycled within an ecosystem.

In a process called denitrification,bacteria convert NO₃^- to N₂.

Nitrogen-fixing bacteria convert atmospheric N₂ into

When Steller sea lions and harbor seals became less plentiful,orcas began using sea otters as a primary food source.

The cause of the sea otter population decline in the Pacific Northwest was primarily an oil spill.

The net primary productivity is the amount of energy

Decomposers

You go on a canoe trip to the Boundary Waters Canoe Area (BWCA) in northern Minnesota. This ecosystem is cold most of the year and receives plenty of rainfall. It has many lakes that are full of walleye pike. You know that walleye like to eat minnows. In turn, the minnows feed on scuds (zooplankton), which eat algae (phytoplankton). -Walleye pike are which of the following?

The energy-requiring process by which liquid water becomes water vapor (a gas)is

Resource partitioning allows only a single species to use a resource.

In the water cycle,animals return water to the environment by

Which of the following is not an important biogeochemical cycle on Earth?

The term abiotic means "nonliving."

A relationship between different species in which one species lives in or on another is

Species that are the first to colonize an area are termed _____ species.

The virus in this study

Some scientists predict that as atmospheric carbon dioxide levels increase,plant growth will also increase.What is the best explanation for this hypothesis?