BIO.5 Ecological Relationships (USATP)

The population of mice in a local forest ecosystem has recently died out due to disease. In the past, these mice were the main predators of the forest beetles.

What is the best prediction about what will happen to the beetles?

• The drop in the mouse population will lead to a drop in the beetle population.

• The drop in the mouse population will lead to no change in the beetle population.

• The drop in the mouse population will lead to an increase in the beetle population.

• The increase in the mouse population will lead to an increase in the beetle population.

Symbiosis is a close relationship between two species in which at least one species benefits. For the other species, the relationship may be positive, negative, or neutral. There are three basic types of symbiosis: mutualism, commensalism, and parasitism. Evaluate each of the relationships depicted in the choices. Select ALL the relationships illustrating commensalism (select 2)

• Hermit crabs use the shells of dead snails for homes.

• Egrets perch on the back of cows and eat the insects that have been disturbed as the cattle forage for food.

• Fleas get food and a warm home by living on hosts such as dogs or cats and biting them to get nutrients from their blood.

• The Egyptian Plover or “Crocodile Bird” will fly into the crocodile’s open mouth and feed on the decomposing meat stuck between their teeth.

• The pilot fish helps to rid the shark of parasites and clean away fragments of food caught between their teeth; it benefits from protection against other predators.

Gavin and Noah disagree on what type of relationship exists between a tapeworm and a cow. The tapeworm uses hooks and suckers to attach to the intestine of the cow, absorbing nutrients directly from the cow's intestinal contents. Gavin says this is an example of parasitism, but Noah claims it is predation. How would you settle their debate?

• This is neither. It is an example of competition because the tapeworm and the cow are competing for food.

• This is predation because the tapeworm kills the cow.

• This is parasitism because the tapeworm kills the cow.

• This is parasitism because the cow is being harmed by the tapeworm living off its nutrients.

The biosphere is the highest level of organization in the hierarchy of life on earth. Rank the levels of organization from most complex to simplest.

• ecosystems > communities > populations > organisms

• organisms > populations > communities > ecosystems

• ecosystems > organisms > communities > populations

• populations > communities > ecosystems > organisms

The graph shows the changes in population of black bears in rural Michigan during a single year. Competition for food among the black bear population was most likely the greatest during the

• winter

• late summer

• late spring

• month of June

In natural ecosystems, the presence of predators lessens the effects of _________________ among the prey.

• competition

• infestation

• parasitism

• mutualism

plants → minnows → bass →bears

Consider the food chain above. What would MOST LIKELY happen if the bass started to disappear because too many of them had been caught during fishing season?

• The number of bear will increase.

• The plant population will increase.

• The number of minnows would increase.

• The number of minnows would decrease.

Impala share the African plains with other grazing animals and predators. Which change would lead to a DECREASE in the impala population?

• a reduction in the lion population

• an increase in the number of other grazing animals

• an increase in restrictions on the hunting of impala

• a reduction in the populations of other impala predators

All of the elephants living in a wildlife preserve would be considered a

• community

• group

• individual.

• population.

Consider each of the examples and select TWO of those that are examples of commensalism.

• A bird builds a nest in a tree.

• Birds use courtship behaviors such as songs to win a mate.

• A tick attaches itself to a dog and sucks its blood to get nutrients.

• A remora rides attached to sharks and other fish and feeds on their leftovers.

• The clownfish feeds on small invertebrates that otherwise have potential to harm the sea anemone, and the fecal matter from the clownfish provides nutrients to the sea anemone.