Question

the winters in 1980 and 1990 were particularly severe. which factor most likely explains the decline in the song sparrow population during these two years?

• loss of habitat
• less food availability
• increased reproductive rate
• increase in predator population

1. (multiple choice) (30 points)

which of the following best describes an ecosystem?

• it is the number of different populations in a specific area or region at a certain time.
• it is the number of individuals of a given species in a specific area at a certain time.
• it is the interaction of one or more communities with abiotic environmental factors.
• it is a group of individuals of a population that depends on the same type of resources in a region.

Explanation:

First Question (About Bird Population Decline)

To determine the factor for the song sparrow population decline, we analyze each option:

• "Loss of habitat" directly affects where birds live, reducing their population.
• "Less food availability" could impact, but habitat loss often drives food issues too.
• "Increased reproductive rate" would increase, not decrease, population.
• "Increase in predator population" is possible, but habitat loss is a more common primary driver for such declines, especially with severe winters (implied by "severe" years) as habitat loss reduces shelter and resources. So loss of habitat is most likely.

Recall the definition of population: it's the number of individuals of a single species in a specific area at a given time.

• First option: Describes community (multiple populations).
• Second option: Matches population definition (one species, specific area, certain time).
• Third option: Describes adaptation or ecological fitting.
• Fourth option: Describes a guild or resource - sharing group, not population.

Answer:

A. loss of habitat

Second Question (Define Population)