Population Ecology

Over a period of 200 years, a mountain pond transformed into a meadow. Which of these explains why new communities replace the old communities?

• the original species all became extinct

• species in the old community died from old age

• diseases that killed the older organisms disappeared

• abiotic characteristics of the habitat changed

In the desert, cactus wrens often build nests in cholla cacti to avoid predators; this does not hurt the cacti. What type of relationship is this?

• competition

• commensalism

• mutualism

• parasitism

If a disease that destroys barley plants in a field swept through an ecosystem, what would happen to the barley eating bird population in the the field?

• The bird population would stay the same

• The bird population would infinitely increase

• The bird population would decrease

The graph shows rabbit population over a 7 year period. What is the approximate carrying capacity for rabbits?

• 200

• 400

• 500

• 600

plants --> rabbits --> foxes --> hawks

Which of these is most likely to occur to the populations immediately after a wildfire burns the environment.

• hawks and foxes increase

• hawks decrease; foxes increase

• plants decrease; rabbits increase

• plants and rabbits decrease

Any thing or organism that regulates the size of a population of another organism is known as __________.

• a limiting measure
• a limiting factor
• factorization
• materialization of precipitation

To measure population density, you must divide the number of individuals living in a defined space by the

• area of the space
• birth and death rates
• carrying capacity
• height of the space

which statement sounds accurate based on the predator-prey graph data. 

• The zebra and lions do not affect each other

• when lions population increases, so does the zebra population

• When the zebra population increases, it causes the lion population to also increase

• when zebra populations go down, the zebra population goes up. 

What do the arrows in the diagram represent?

• flow of water

• flow of sunlight

• flow of energy

• flow of bacteria

A scientist measured flower heights at many different elevations on a mountain. Which statement best describes the pattern of growth for flowers during the experiment?

• flower height is unaffected by elevation

• flower height decreases with decreasing elevation

• flowers grow taller around elevations of 3000 meters

• flower height increases with increasing elevation