Exam 4: Populations and Communities

Some biologists have identified symbiotic relationships in which it appears that one organism gains from the relationship while the other organism is unaffected.Although after further research,the researchers find out that both members of the relationship actually benefit.The researchers therefore realize that what they at first thought was an example of

Dung beetles live in regions where cattle graze,quickly burying and recycling cattle droppings.Because of the dung beetle's activities,breeding habitats and resources for disease-carrying flies are reduced and the plants upon which cattle feed are nourished. -The relationship between the dung beetles and the cattle is a type of

A population would be expected to grow if

Threatened and endangered species receive special protection from human activities such as hunting and habitat destruction because these activities may continue despite the species' low numbers.These human activities therefore

Darwin and Wallace discovered natural selection without knowledge of an important field of biology that is very much a part of biological evolution.What essential part of biological evolution was poorly understood when they first presented natural selection to the world?

The risk of introducing a natural enemy to control an invasive species is that

Which one of the following illustrates interspecific competition?

Golden frog populations would be more likely to survive the current threats if

Resource partitioning

The unusual organisms living in Australia have evolved primarily because of

In North America,a toxic weed called leafy spurge was accidentally introduced and has grown and spread rapidly,covering millions of acres in north central United States and south central Canada.Leafy spurge is generally avoided by cattle and horses and may be toxic to them.Thus,rangeland where leafy spurge has spread has been damaged by the invasion of this plant. -Leafy spurge has spread completely across many US states.If left uncontrolled in these states,leafy spurge populations will

Sumatran rhino populations have declined steadily to a point near extinction.Because of its population decline,this unusual forest-dwelling rhino is near its

Which one of the following is characteristic of a K-selected species?

The fluid core of the Earth

The most stable predator-prey relationships typically involve

Along the shoreline of a pond,Canadian geese,American toads,and grass frogs search for food while bluegill and bass prey on small fish in the shallow water.These species,living and feeding in this particular location,represent one

The concept of biological fitness is based on two separate abilities.These are the ability to

Genetic diversity in a species does not arise from

Over the last 100 years,the number of elk in Yellowstone has varied in part because of the limited availability of winter food sources and many types of predators,including wolves (eliminated in 1926 and reintroduced in 1995),grizzly bears,coyotes,black bears,and golden eagles. -The population of elk in Yellowstone

Many predator-prey relationships do not result in the complete elimination of the prey because