A food chain is shown.
Which model best represents the amount of energy available for the use of each trophic level represented in the food chain?
The diagram shows a partial East Texas food web.
Which table correctly classifies these organisms?
A partial Texas food web is shown.
The populations of which organisms will most likely increase as a result of a disease that suddenly reduced the population of Texas horned lizards?
A partial coastal food web is shown.
What is one effect the removal of herring would have on the food web?
In a grassland ecosystem, a severe drought causes a significant loss of plant life. How would this change affect the rest of the ecosystem?
Purple loosestrife is an invasive flowering plant species now found in North America. In an effort to control the purple loosestrife, biologists tested and released three beetle species to use as a biological control of the plant.

Which result is an unintended negative consequence of releasing these beetle species into the environment?
Kelp forests are critical ecosystems that provide habitats to a variety of animals, including sea urchins, sea stars, sea anemones, crabs, jellyfish, snails, and fish. They also provide hunting grounds for mammals, including sea otters, sea lions, seals, and many different birds. In recent years scientists have documented an increase in shark attacks on sea otters in and around kelp forests.
Which consequence is most likely to occur in kelp forests as a result of increased predation of sea otters?
The San Marcos salamander, Eurycea nana, is a light reddish-brown translucent salamander about 2-5 cm in length. E. nana is found only in Spring Lake and a portion of the San Marcos River.
Which human activity would most likely decrease the ability of the salamanders to survive?
A large section of the Amazon rainforest has been cleared to make way for agriculture. This deforestation has led to habitat loss for many species, including jaguars, macaws, and poison dart frogs. Additionally, the removal of trees has reduced the amount of carbon dioxide absorbed from the atmosphere.
Which of the following is the most likely consequence of this environmental change?
A group of scientists studying Arctic ecosystems has observed that as global temperatures rise, sea ice is melting earlier in the year. This change has made it harder for polar bears to hunt seals, leading to a decline in polar bear populations.
How is this environmental change most likely to affect the Arctic food web?
The accompanying diagram illustrates the relationship between organisms and an ecosystem.

Which change would most likely reduce the population of the carnivorous fish?
Off the coast of Australia, the Great Barrier Reef is home to thousands of marine species. Coral reefs provide shelter and breeding grounds for fish, sea turtles, and invertebrates. However, rising ocean temperatures and pollution have caused widespread coral bleaching, weakening the reef structure and reducing available habitat.
What is the most likely outcome if coral bleaching continues?