Deck 6 (slides 28-34)

Nitrogen is made available to living things by the ________ cycle.

The nitrogen cycle is carried out by _________ _________ bacteria that live in the root nodes of _________ (such as beans, peas, peanuts).

A main component of fertilizer is nitrogen, which is why farmers spread _________ on fields and farmers some years grow _____ _______ in their fields.

Organisms need nutrients to _______.

If a nutrient is in short supply (thus limiting an organism’s growth), that nutrient is called a __________ _________.

An example of nutrient limitation is when coastal ocean water often contains sufficient supplies of several nutrients to support much more algae growth than is normally present. The algae growth is slowed however by a lack of ________, so in this case, ________ is the limiting factor (this is a good thing).

An example of nutrient limitation is if nitrogen is suddenly added to the ecosystem (such as fertilizer runoff from farmland), nitrogen is ____ ________ a limiting factor. This results in a tremendous ______ ________ _________ on the surface of the ocean (red tide) which can cover the surface of the water.

When a red tide occurs, plants below die because they receive no _______.

When a red tide occurs, bacteria grow and use up much of the _____ in the water, which can cause marine animals to __________.

Population growth begins when a few individuals of a species are introduced into a _____ environment and at first their numbers begin to grow _________.

Soon after the numbers of the species in a new environment are growing slowly, the population begins to grow rapidly, called ___________ _________.

During exponential growth, the birth rate is much _________ than the death rate.

Exponential growth does not _____ long; the population growth _______ as the death rate catches the birth rate.

After the birth rate and death rate become the same, the population growth ______ and the number of organisms in the population remains the same, called a _________ _______.

During the steady state, the average growth rate is ____ (the population still rises and falls, but they average out around a certain population size for that species in the particular environment); this is called the __________ __________ of the environment.

Once a population reaches the carrying capacity of its environment, certain _________ keep the population from growing any further.

Factors that control population growth are called _________ __________ factors.

One density dependent factor is ________ for resources.

Examples of resources that are competed for are _______, ________, _______ _______, _________.

Each organism has a specific role it plays in he ecosystem, called a ________.

Anytime 2 species occupy the same niche, they will _________ with each other (such as eating the same type of food).

Competition for resources ________ the size of the population of each species.

Competition for resources causes both species to find themselves under pressure to _______ in ways that ________ their competition or one will become extinct.

A niche is defined by the way the organism _________ with the loving and nonliving components of its ecosystem, such as what it eats and what habitat it prefers.