Principles of Environmental Science
Chapter 2- From Species to Ecosystems
Objective: Why are big, fierce animals so rare?
 Species mean kind in Latin and in biology species refers to all organisms of
the same kind that are genetically similar enough to breed in nature and
produce live, fertile offspring.
 Organisms occur in populations, communities, and ecosystems.
o Population is all the members of a species living in a given area at the
same time.
o A biocoenosis or biological community is all of the populations of
organisms living and interacting in a particular area.
o An ecosystem is composed of a biological community and its physical
environment.
 Food chains, food webs, and trophic levels link species.
o Producers are the organisms in the ecosystem that photosynthesize.
(Green plants and algae).
o Consumers are organisms that obtain energy and nutrients by feeding
on other organisms or their remains.
o One of the most important properties of an ecosystem is its
productivity.
o Biomass is the biological material produced by living organisms.
o Food chains are interconnected to form food webs.
o Trophic levels show an organism's feeding status within an ecosystem.
o Herbivores eat plants.
o Carnivores eat meat.
o Omnivores eat both plants and animals.
o Scavengers feed off dead animals.
o Detritivores eat litter and other debris.
o Decomposers eat dead organisms.
 Ecological pyramids describe trophic levels.
Lesson/Activity Ideas:
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Endangered Ecosystems
Build an Online Habitat
Looking at Ecosystems
Ecosystem Lesson Plans
Caught in the Act
 Have students choose an animal and research its role in the ecosystem. As a
class you can create web and place pictures of the animals where they
belong on the web.
 Students can also research endangered animals. They can find the
endangered animal’s role in the ecosystem and can perhaps determine what
makes it endangered.
 After researching endangered animals, as a class you can either choose one
or pick the most endangered and adopt it from the World Wildlife
Federation.
 Adopt an Animal