Interactions in Nature
Study Guide
Vocabulary Review: Review some key terms with an interactive learning game at:
http://www.quia.com/jg/98665.html
You may need Java to run this. Ask your parents for help or practice at school when
you are given technology time.
You will need to know these key vocabulary words in order to answer multiple
choice and/or short answer type questions that apply what you know.
Science Journal Review: Study all entries related to ecosystems, food
chains/webs, adaptations, and effects of change.
You should know:
A single organism living in its environment is called an individual.
Individuals of the same kind living in the same environment make up a population.
All of the populations of organisms living together in an environment make up a
community.
A community and its physical environment make up an ecosystem.
The place where a population lives in an ecosystem is its habitat.
The role or job of a population within its habitat that enable it to share resources is
its niche.
Limiting factors are any resources in an environment that can impact the success
of a population. Soil conditions, temperature, and amount of rainfall can be limiting
factors for plants. The number and type of plants can be a limiting factor for
animals. Can you explain why?
What provides the energy for almost every ecosystem on Earth? the Sun
Producers – are plants that use the sunlight to make the food they need from
carbon dioxide and water.
Consumers – organisms in an ecosystem that must eat to get the energy they; they
get their energy from the producers they eat.
Decomposers – consumers that break down tissues of dead organisms and return
some nutrients to the soil, which results in helping producers grow. In this way,
decomposers connect both ends of the food chain. Ex: mushrooms & bacteria
Food chains – show how organisms in an ecosystem are connected to one another
by what they eat. The arrows show how the energy flows through the organisms
from the producer to the first-level consumer to the second-level consumer, etc.
Food web – shows the relationships between many different food chains in a single
ecosystem. Food webs are a better model of an ecosystem because one plant can be
a producer in many different food chains and consumers can be members of several
different food chains, too.
Energy pyramid – a model that shows the amount of energy available to pass from
one level of a food chain to the next.
Can you label the organisms in a food chain/web as producer, consumer, decomposer,
predator, prey, etc. and show which direction the energy flows? Can you explain which
organism is always at the beginning of a food chain? Can you explain which organism
is always at the bottom of an energy pyramid and why the bottom section of an energy
pyramid is always the largest section?
Think of an animal that you have observed or learned about in class that is uniquely
adapted for a particular niche in its habitat. Do the animal’s adaptations help it share
or compete more effectively for resources? How do the animal’s adaptations help it
survive? Study the picture of the elephant below to learn about some of its
adaptations and see how they aid its survival.
Decline in animal and plant populations can be due to human activities, such as:
1) Hunting that leads to direct declines in populations/poaching
2) importing nonnative, exotic organisms into the country with diseases that
can harm native populations
3) construction of man-made roads, homes and businesses that can reduce the
size of natural habitats
4) resource extraction – strip mining
5) pollution
Change in environments caused by humans usually cause significant and sometimes
permanent damage to populations.
Natural events that can change the environment and cause population decline
include:
1) floods
2) fires
3) droughts
4) volcanic eruptions or other storms, such as hurricanes/tsunamis
Most natural changes are temporary and healthy populations usually survive.
Overgrazing and imbalanced numbers of organisms interacting in a food chain/web
in an area can also harm an ecosystem.
Can you explain how man and/or nature could cause a decline in the population
numbers of many organisms in a community? Can you think of ways in which man in
particular could avoid harming animal and plant populations?
BrainPop is a great place for additional review and practice. For our school account,
log on at: www.brainpop.com
Username: lakesidepop
Password: longhorns
Our school account is only available to students between 7:00AM – 5:30PM.
Suggested video lessons and quizzes include the following titles:
 Ecosystems
 Energy Pyramid
 Food Chains (Free and available at all times by the public)
 Camouflage & Hibernation might also help you learn more about Adaptations