AutotrophHeterotroph

Food Web

Energy Flow

Energy Pyramids:

Habitats, Niches, and Community Interactions 4.2: Pg

Biotic and Abiotic Factors Ecosystems are influenced by a combination of biological and physical factors Biotic Factors: the biological influences on organisms Abiotic Factors: Physical, or nonliving, factors –i.e. temp, precipitation, humidity, wind, nutrient availability, soil, sunlight, etc.

Habitats and Niches Habitat: the area where an organism lives. Includes both the biotic & abiotic factors Niche: the full range of physical & biological conditions in which an organism lives & the way in which the organism uses those conditions

Niche includes… Place in the food web Range of temp. organism needs to survive Type of food organism eats How it obtains food Who uses the organism for food Physical conditions required to survive When & how organism reproduces

Competitive Exclusion Principle No two species can share a niche in the same habitat!!...example is the Warblers…

Warbler Niches Each of these warbler species has a different niche in its spruce tree habitat. By feeding in different areas of the tree, the birds avoid competing with one another for food.

Community Interactions Community interactions, such as competition, predation, and various forms of symbiosis can powerfully affect an ecosystem.

Competition Competition: occurs when organisms of the same or different species attempt to use a resource at the same place and time. Trees in competition for light

Predation Predation : one organism captures and feeds on another Lynx and Hare

Symbiosis Symbiosis: Any relationship in which two species live closely together –Mutualism: both species benefit Hummingbird and Flower Clownfish and sea anemone

–Commensalism: one species benefits, other neither harmed nor helped Barnacles on a whale

–Parasitism: one organism lives in or in another & harms it A flea or tick feeds on the blood of its host and may also carry disease-causing microorganisms Mistletoe in a tree

Characteristics of Populations 5.1 pg

Characteristics of Populations are: 1.Geographic distribution (area inhabited by population) 2.Density 3.Growth rate 4.Age structure

Factors that affect population size are: 1.Number of births 2.Number of deaths 3.Number of individuals that enter or leave population Immigration – move in Emigration – move out

If a population has abundant space and food and is protected from predators & disease, then organisms will multiply and the population will increase.

Exponential growth occurs when the individuals of a population reproduce at a constant rate. J-shaped Curve – Exponential growth Occurs under ideal conditions with unlimited resources (Has not reached its carrying capacity)

S-shaped curve – Logistic Growth Carrying capacity – largest number of individuals that a given environment can support Populations are limited by space, food, etc.