organism
A prairie dog is one type of ----- or living thing.
habitat
An environment that provides the things the organism needs to live, grow, and reproduce is called its -----.
biotic factors
The living parts of a habitat are called -----
Abiotic factors
----- are the nonliving parts of an organism's habitat.
photosynthesis
Plants and algae need water, along with sunlight and carbon dioxide, to make their own food in a process called -----.
species
A ----- is a group of organisms that are physically similar and can mate with each other and produce offspring that can also mate and reproduce.
population
All the members of one species in a particular area are referred to as a -----.
community
All the different populations that live
together in an area make up a -----
ecosystem
The community of organisms that live in a par-
ticular area, along with their nonliving surroundings, make up an -----
ecology
The study of how living things interact with each
other and with their environment is called ----.
birth rate
The ----- of a population is the number of births in a population in a certain amount of time.
death rate
The ------ is the number of deaths in a population in a certain amount of time.
Immigration
----- means moving into a population.
Emigration
----- means leaving a population.
limiting factor
A ------ is an environmental factor that causes a population to stop growing.
carrying capacity
The largest population that an area can support is called its -----.
producer
An organism that can make its own food is a
-----.
consumer
An organism that obtains energy by feeding on other organisms is a -----.
herbivores
Consumers are classified by what they eat. Con-
sumers that eat only plants are -----.
carnivores
Consumers that eat only animals are -----.
omnivores
Consumers that eat both plants and animals are -----.
scavenger
A ----- is a carnivore that feeds on the bodies of dead organisms.
Decomposers
----- break down wastes and dead organisms and return the raw materials to
the ecosystem.
food chain
A ------ is a series of events in which one
organism eats another and obtains energy.
food web
A ----- consists of the many overlapping food chains in an ecosystem.
energy pyramid
A diagram called an ----- shows the amount of energy that moves from one feeding level to another in a food web.
natural selection
A characteristic that makes an individual better suited to its environment may eventually become common in that species through a process called -----.
adaptations
In this way, natural selection results in -----, the behaviors and physical characteristics that allow organisms to live successfully in their environments.
niche
The role of an organism in its habitat, or how it makes its living, is called its -----.
competition
The reason for this is -----, the
struggle between organisms to survive as they attempt to use the same limited resource.
predation
An interaction in which one organism kills another for food is called -----
predator
The organism that does the killing, in
this case the tiger shark, is the -----.
prey
The organism that is killed, in this case the albatross, is the -----.
Symbiosis
------ is a close relationship between two species that benefits at least one of the species.
mutualism
A relationship in which both species benefit is
called ------.
commensalism
A relationship in which one species bene-
fits and the other species is neither helped nor harmed is called ------.
Parasitism
----- involves one
organism living on or inside another organism and harming it.
parasite
The organism that benefits is called a ------, and the organism it lives on or in is called a host.
host
The organism that benefits is called a parasite, and the organism it lives on or in is called a ------.
nitrogen fixation
The process of changing free nitrogen into a usable form of nitrogen is called -----.
succession
The series of predictable changes that occurin a community over time is called -----.
Primary succession
------ is the series of changes that occur in an area where no soil or organisms exist.
pioneer species
The first species to populate the area are called -----.
Secondary succession
----- is the series of
changes that occur in an area where the ecosystem has been disturbed, but where soil and organisms still exist.