I. How Organisms Interact

Some interactions among species are the result of a long evolutionary history in which many of the participants adjust to one another over time.

A.Types of Species Interactions:

1. Predator / Prey

2. Symbiosis

1. Predation – The act of one organism killing another for food.

-One of the most basic forms of relationships between organisms.

-Often characterized by various prey acquisition and predator avoidance tactics.

Predators

SpeedAmbushSpecialized

structures/products

Group/pack hunting

Prey

Camouflage Chemical

warfareWarning

colorsMimicry

2. Symbiosis- Relationship where species live together

Three types of symbiotic relationships

A. Parasitism- one organism living in or on another, often causing harm

B. Mutualism- two or more organisms living together benefiting each.

C. Commensalism- two or more organisms living together, one benefiting, one neither helped or harmed.

II. How Competition Shapes Communities

A. Competition – The interaction between organisms either of the same or different species that require the same resources.Two types:

1. Intraspecific - Competition between members of the same species

2. Interspecific:-Competition between 2 or more different species

B. Niche – the role or “job” of an organism within its environment.

*Described in terms of how the organism affects energy flow within the ecosystem in which it lives.

* If the resources of organisms with overlapping niches are in short supply, it is likely that their will be competition between the organisms.

*Niche sizes categorized as;

•Fundamental Niche

•Realized Niche

1. Competition with Limitations of Resources

RESOURCE PARTITIONING

2. Competition without Limitations

of Resources

COMPETITIVE EXCLUSION

III. Major Biological Communities

Where an organism lives often depends on an areas CLIMATE

CLIMATE -

THE PREVAILING WEATHER CONDITIONS IN ANY GIVEN AREA.

THE TWO MOST IMPORTANT elements of climate are temperature and moisture

A. Categories of ecosystems…

1. Biomes 2. Aquatic Life ZonesBiomes:

-Land portion of the biosphere

-Distinct CLIMATE and specific life-forms adapted for life within that climate.

15,000 ft10,000 ft5,000 ft

Coastalmountainranges

SierraNevadaMountain

GreatAmericanDesert

RockyMountains

GreatPlains

MississippiRiver Valley

AppalachianMountains

Coastal chaparraland scrub

DesertConiferousforest

Coniferousforest

Prairiegrassland

Deciduous

forest

Average annual precipitation

100-125 cm (40-50 in.)

75-100 cm (30-40 in.)

50-75 cm (20-30 in.)

25-50 cm (10-20 in.)

below 25 cm (0-10 in.)

2. Aquatic life zones:

Marine – those that contain raised levels of salt

(Estuaries, Coastlines, Reefs, Oceans)

Freshwater

(Lakes,Streams,& Wetlands)

Body Snatchers