Environment Science

1. Review Questions Chapter V (Page 102)
Environments and Organisms
Questions
1. Define environment.
2. Describe, in detail, the niche of a human.
3. How is natural selection related to the concept of niche?
4. List five predators and their prey organisms.
5. How is an ecosystem different from a community?
6. Humans raising cattle for food is what kind of relationship?
7. Give examples of organisms that are herbivores, carnivores, and omnivores.
8. What are some different tropic levels in an ecosystem?
9. Describe the carbon cycle, the nitrogen cycle, and the phosphorus cycle.
10. Analyze an aquarium as an ecosystem. Identify the major abiotic and biotic factors. List
members of the producer, primary consumer, secondary consumer, and decomposer
tropic levels.

2. Answers
1. Define environment.
 Everything that affects an organism during its lifetime is collectively known as its
environment. The environment of an organism can be divided into biotic (living) and
abiotic (non-living) components.
o Living (biotic factors) of an organism’s environment include all forms of life
with which it interacts.
o Nonliving (abiotic factors) : energy, nonliving matter, and processes that
involve the interactions of nonliving matter and energy.
2. Describe, in detail, the niche of a human.
 The role organism plays in its environment is known as its niche. The niche of a species
is the result of natural selection directing the adaptation of the species to a specific set of
environmental conditions. The ecological niche of an organism is a complex set of
interactions between an organism and its surroundings, which includes all of the ways an
organism influences its surroundings as well as of the ways the organism is affected by
its environment.
o Example: Human use the plant for food, need the air for breathing, need sunlight for
growth and strong.
3. How is natural selection related to the concept of niche?
 Natural selection is the process whereby successful organisms pass on the
characteristics which made them successful to their offspring. In this way, each
organism is finely tuned to a particular habitat and niche, and unfit individuals are
removed from the population.
4. List five predators and their prey organisms.
 Predators and their prey organisms relationships include lion and zebras, eagles
and mice, osprey and fish, robins and worms, frogs and insects, baleen whales and
zooplankton.
5. How is an ecosystem different from a community?
 An ecosystem is defined space in which interactions take place between a
community, with all its complex interrelationships, and the physical environment.
Some ecosystems, such as grasslands and certain kinds of forests, are shaped by

3. periodic fires. The kind of soil and the amount of moisture also influence the
kinds of organisms found in an area.
 A community is an assemblage of all the interacting populations of different
species of organisms in an area. Some species play minor roles, while others play
major roles, but all are part of the community. For example, the grasses of the
prairie have a major role since they carry on photosynthesis and provide food and
shelter for the animals that live in the area.
6. Humans raising cattle for food is what kind of relationship?
 Humans raising cattle for food is technically a form of predation. Humans are
secondary consumers feeding on the cattle which are primary consumers feeding
on the plants which are primary producers. It could be argued however, that it is a
type of mutualistic relationship in which both populations benefit, because the
cattle has been so changed that it cannot survive without human interaction.
7. Give examples of organisms that are herbivores, carnivores, and omnivores.
 Examples of herbivores include seed-eating birds, deer, rabbits, and zooplankton.
Examples of carnivores include wolves, falcons, and sharks. Examples of
omnivores include humans, bears, and raccoons.
8. What are some different tropic levels in an ecosystem?
 Trophic levels in an ecosystem include producers, herbivores, carnivores,
omnivores, and decomposers.
9. Describe the carbon cycle, the nitrogen cycle, and the phosphorus cycle.
 Carbon cycle: Carbon atoms are cycled through ecosystem. Plants can
incorporate carbon atoms from carbon dioxide into organic waste or dead
organism are consumed by decay organism. All organisms, plants, animals, and
decomposer return carbon atoms to the atmosphere when they carry on
respiration. Oxygen atoms are being cycled at the same time that carbon atoms are
being cycled.
 Nitrogen cycle: Nitrogen atoms are cycled in ecosystem. Atmospheric nitrogen
is converted by nitrogen- fixing bacteria to a form that waste product are acted on
be decay organism to form ammonia, which may be reused by plants or
converted to other nitrogen compounds by other kinds of bacteria. Denitrifying

4. bacteria are able to convert inorganic nitrogen compounds into atmospheric
nitrogen.
 Phosphorus cycle: The source of phosphorus is rock that, when dissolved,
provides the phosphate used by plants and animals.
10. Analyze an aquarium as an ecosystem. Identify the major abiotic and biotic
factors. List members of the producer, primary consumer, secondary consumer, and
decomposer tropic levels.
 Analyze an aquarium as an ecosystem. Identify the major abiotic and biotic
factors. List members of the producer, primary consumer, secondary consumer,
and decomposer trophic levels.
 Analyze an aquarium as an ecosystem.
 Aquarium is a building where people go to look at fish and other
water animals. Analyze an aquarium as an ecosystem is light,
temperature, salinity, dissolved oxygen, and nutrients.
 Identify the major abiotic and biotic factors.
 Biotic Factors (living) of an organism’s environment include all
forms of life with which it interacts.
 Abiotic Factors (nonliving) can be organized into several
categories: energy, nonliving matter, and processes that involve
the interactions of nonliving matter and energy.
 List members of the producer, primary consumer, secondary consumer,
and decomposer trophic levels.
 Producer
o Grass, algae, phytoplankton, tree, flower, fern, or moss.
 Primary consumer
o Grasshopper, mosquito larva, dragonfly larva, or
zooplankton.
 Secondary consumer
o Rat, dragonfly larva, or fish.
 Decomposer
o Fungi, bacteria, some insects, and worms.