II. Community Interactions (Chp 48)Def. “all the populations of organisms inhabiting a

common environment and interacting with one another”

Types of Interactions

A. Competition

1. Competitive exclusion - when two species use the same limiting

resource, one is always eliminated e.g. Paramecium caudatum and P. aurelia

2. Ecological niche - an organism’s role in the environment (its profession, not its address)a. Fundamental niche - determined by the

physiological limits of the organismb. Realized niche - the portion of the

fundamental niche actually utilized due to interactions with other species

• e.g. Chthamalus and Balanus barnacles

c. Niche Partitioning – closely related organisms that require the same resource will overlap little to to allow competing species to coexist

• e.g. five species of warblers

• The liquid inside young coconuts can be used as a substitute for blood plasma.

• No piece of paper can be folded in half more than seven (7) times.

• Donkeys kill more people annually than plane crashes.

• You burn more calories sleeping than you do watching television.

• Oak trees do not produce acorns until they are fifty (50) years of age or older.

• The first product to have a bar code was Wrigley's gum.

• The king of hearts is the only king without a mustache.

• American Airlines saved $40,000 in 1987 by eliminating one (1) olive from each salad served in first-class.

• Venus is the only planet that rotates clockwise.

• Apples, not caffeine, are more efficient at waking you up in the morning.

Think You Know Everything??????????

B. Predation - eating of live organisms by animals, plants, or fungi

1. Population control

2. Increases species diversity - keystone predators maintain diversity by

controlling the number of potentially dominant species

i. Sea Stars (Pisaster) – control abundance of mussels and barnacles

ii. Periwinkles (snails) – control diversity of algal species

3. Drives evolution of predator and prey speciesa. Speed, strength, teeth, intelligenceb. Defensive adaptations in plants

i. Structures - thorns and spinesii. Chemicals - nicotine, morphine, strychnine (poison), and cinnamon, cloves,

or peppermint (distasteful)c. Defensive adaptation in animals

i. Concealment and camouflage - freezing, burrows, protective coloration, warning coloration, disguised appearance (walking stick, peppered moth, frog looking like bird dropping)ii. Disagreeable taste, odor, or spray - stink bug, monarch butterfly, bombardier beetle

Bombardier beetles (Brachinus spp.) inject an explosive mixture of hydroquinone, hydrogen peroxide plus several potent catalysts into a reaction chamber in the abdomen. Catalase breaks down the hydrogen peroxide into water and oxygen gas. Peroxidase oxidizes hydroquinone into benzoquinone. The mixture of chemicals and enzymes volatilizes instantly upon contact with the air, generating a puff of "smoke"" and an audible popping sound. This caustic flatulence is totally controlled by the beetle, otherwise it might accidentally blow up its rear end. The explosive discharge apparently discourages predators, either by chemical irritation, heat or repugnance. The temperature of the explosive mixture of gasses and fluids is over 100 degrees Celsius, the boiling point of water.

iii. Mullerian mimicry - using similar warning coloration

e.g. Yellow jacket, sandwasp

iv. Batesian mimicry - harmless species mimics unpalatable or dangerous species

e.g. viceroy and monarch butterflies, flies and bees, hawkmoth larva and snake

Most dust particles in your house are made from dead skin.

The first owner of the Marlboro Company died of lung cancer. So did the first "Marlboro Man."

Walt Disney was afraid of mice.

Pearls melt in vinegar.

It is possible to lead a cow upstairs...but not downstairs.

A duck's quack doesn't echo, and no one knows why.

Dentists have recommended that a toothbrush be kept at least six (6) feet away from a toilet to avoid airborne particles resulting from the flush.

Richard Millhouse Nixon was the first U.S. president whose name contains all the letters from the word "criminal." The second? William Jefferson Clinton.

Turtles can breathe through their butts

C. Symbiosis - close and long term association between two species,

e.g. lichens = fungi + algae

1. Parasitism - one organism benefits, one is harmed- Plasmodium (malaria) -mosquito- tapeworm

2. Mutualism - beneficial to both organisms- nitrogen-fixing bacteria- PS algae in coral tissues- acacias and ants- protists in termite gut- mycorrhiza = roots and fungi- Leaf-cutter ant and fungus

3. Commensalism - beneficial to one, no effect on other (hitchhikers)- barnacles attached to whales- worm in sea cucumber's anus- clownfish and anemone