6.1 Quiz

Fungi, many birds, and a wide variety of insects all share the​ (a)   of a tree in the forest. Part of the ​ (b)   of the fungi is to obtain energy from dead organic matter, such as dead wood. Temperatures above 0°C and sufficient water in the environment help define the range of​ (c)   for fungi.

• Habitat
• Niche
• Tolerance
• energy source
• symbiosis

A flea and dog are an example of ​ (a)   because the flea irritates the dog's skin and feeds on its blood. Certain bacteria live in the digestive tract of humans, and their relationship is an example of ​ (b)   because the bacteria help humans to break down the food they eat. Cattle egrets eat insects off the back of an elephant, which is an example of ​ (c)   because the cattle egrets benefit without either harming or helping the elephants.

• Parasitism
• Mutualism
• Commensalism

In a science experiment, equal-sized populations of two species of earthworms are placed in a terrarium filled with soil. Abiotic factors such as temperature and water supply are kept constant in the terrarium, as is food in the form of bread scraps. The population of each species is observed and counted each day. In agreement with the competitive exclusion principle, what is the most likely outcome of the experiment over time?

• Only one population will thrive; the other population will decrease to zero.

• Both populations will reach the same size, which is the carrying capacity of the terrarium for earthworms.

• One population will be about twice the size of the other.

• Both populations will reach the same size, which is about half the carrying capacity of the terrarium for earthworms.

Which is an example of herbivory affecting an ecosystem?

• Tall trees block the sunlight from reaching plants on the forest floor.

• Coyotes catch slow-moving rabbits, but not the faster rabbits.

• Deer eat the stems of plants without thorns, allowing plants with thorny stems to thrive.

• Fungi break down dead organic matter, which returns nutrients to the soil.

Alligators are predators that live in the Florida Everglades. A scientist is using a computer model to determine whether the alligator is a keystone species in the Everglades. The graph shows the population of alligators in one of the computer simulations. The simulation also provides data for many other Everglades species. Which of these results would provide the strongest evidence that the alligator is a keystone species?

• The populations of many species increase and decrease in a similar pattern as the alligator.

• The populations of many species are always increasing, regardless of the changes to the alligator population.

• The populations of many species are always decreasing, regardless of the changes to the alligator population.

• The populations of other species are staying about the same, regardless of the changes to the alligator population.

Soil pH is a measure of the acid content of the soil. The graph shows the tolerance of earthworms to soil pH. In a meadow where earthworms live in the soil, the pH gradually decreases from the optimum range into the zone of stress. What is the MOST LIKELY effect on the earthworm population?

• The size of the earthworm population increases, but otherwise the population is unchanged.

• The size of the earthworm population decreases, but otherwise the population is unchanged.

• Earthworms that tolerate high pH become more common in the population.

• Earthworms that tolerate low pH become more common in the population.

Yasmine states that tapeworms are common parasites of goats. Walter claims that the relationship between a tapeworm and goat should be classified as predator and prey. Which fact about tapeworms and goats is MOST useful for Yasmine to cite to refute Walter's claim?

• Tapeworms get their energy from food that they obtain from goats.

• Tapeworms benefit from their relationship with goats.

• Goats do not benefit from their relationship with tapeworms.

• Tapeworms live inside a goat's body in a close relationship the goat.