Chapter 4 Test

Front

Simplest level of organization studied by ecologists

Back

individual

Answer explanation

The simplest level of organization that ecologists study is the individual organism. The levels of ecological organization, from simplest to most complex, are:

1. Individual organism

2. Population (a group of individuals of the same species)

3. Community (different populations living together)

4. Ecosystem (community plus the physical environment)

5. Biosphere (all ecosystems on Earth)

Front

A herd of mule deer on a mountain

Back

species

Answer explanation

A species is a group of organisms that can interbreed and produce fertile offspring. The correct term for a herd of mule deer living in a specific area is a population. If they had not been separated from the other mule deer, the answer would have been population consists of individuals of the same species living in a particular area.

Front

Giraffes, lions, zebras, hyenas of the Serengeti

Back

Community

Answer explanation

All these living things together form a biological community within the Serengeti ecosystem. This community includes all the interacting species in a specific area, contributing to the overall biodiversity and ecological balance.

Front

Study of vegetation, animals, soil, and water in saltmarsh

Back

Ecosystem

Answer explanation

Here’s why:

• An ecosystem includes all the interactions among living organisms (vegetation and animals) and their physical environment (soil minerals and water levels).

• A population (A) refers to individuals of a single species in a specific area.

• A biosphere (B) encompasses all ecosystems on Earth.

• A community © includes all the living organisms in a specific area but not their physical environment.

Front

Definition of all living things and their physical environment

Back

Ecosystem

Answer explanation

An ecosystem includes both the biotic (living) components, such as plants, animals, and microorganisms, and the abiotic (non-living) components, like air, water, and minerals, interacting in a specific area.

Front

Highest population density of grasshoppers

Back

35 grasshoppers/10 square meters

Answer explanation

To determine the highest population density of grasshoppers, we need to calculate the number of grasshoppers per square meter for each option:

• A. 35 grasshoppers/10 square meters = 3.5 grasshoppers per square meter

• B. 40 grasshoppers/20 square meters = 2 grasshoppers per square meter

• C. 1 grasshopper/1 square meter = 1 grasshopper per square meter

• D. 50 grasshoppers/30 square meters = 1.67 grasshoppers per square meter

Front

Clumped distribution pattern?

Back

False

Answer explanation

Front

Population growth indicator

Back

Diagram A

Answer explanation

This diagram has a broad base, indicating a large proportion of individuals in the pre-reproductive age group, which suggests a high potential for future population growth as these individuals mature and start reproducing

Front

Population needing attention

Back

C

Answer explanation

This diagram shows a narrow base, indicating a small proportion of individuals in the pre-reproductive age group. This suggests that there are not enough young deer to replace the older individuals as they die, leading to a potential decline in the population over time.

Focusing on this population would involve strategies to increase the number of young deer, such as improving habitat conditions, ensuring adequate food supply, and possibly managing breeding programs to boost the reproductive success of the remaining individuals.

Front

Population at carrying capacity

Back

B

Answer explanation

Population B has reached carrying capacity. This is evident from its age structure diagram, which shows a nearly vertical pyramid with a broad base. The population has a roughly equal number of individuals across various age groups, indicating a stable population where birth rates are balanced by death rates. This balance suggests that the population is neither growing nor shrinking significantly, which is characteristic of a population at carrying capacity.