4.4

4.4

Web of Life

Web of Life

• Everything living is connected• One organism can positively or negatively

affect the balance of the web

Relationships

1. Predator – prey2. Commensalism3. Mutualism4. Parasitism5. Keystone Species

Predator/ Prey

• Predator is an organism that eats another organism. • Prey is the organism which the predator eats. • lion and zebra• Bear and fish• fox and rabbit• Bear and berry• rabbit and lettuce• grasshopper and leaf.

Commensalism

• Symbiotic relationship• Relationship in which one member benefits • while the other member is unaffected. • Birds and trees have this type of relationship.

Clownfishes and Sea Anemones

•The CLOWNFISH lives among the forest of tentacles of an anemone and is protected from potential predators not immune to the sting of the anemone.• The anemonefish is protected from the sting of the anomone tentacles by a substance contained in the mucous on its skin.

Parasitic relationship

• Symbiotic relationship• One organism, the parasite, lives off of

another organism, the host, harming it and possibly causing death.

• The parasite lives on or in the body of the host.

• A few examples of parasites are tapeworms, fleas, and barnacles.

Tapeworms

• Segmented flatworms that attach themselves to the insides of the intestines of animals such as cows, pigs, and humans.

• They get food by eating the host's partly digested food, depriving the host of nutrients.

Fleas

• Bite host skin, sucking their blood, and causing them to itch.

• The fleas, in turn, get food and a warm home.

Barnacles

• Live on the bodies of whales, do not seriously harm their hosts, but they do itch and are annoying.

Aphids

• Insects that eat the sap from the plants on which they live.

Fungus

• can attack animals• Lumpy jaw, a disease that injures the jaws of

cattle and hogs

Ticks

• Carry and transmit disease. • Lyme disease is transmitted by deer ticks.

Mutualism

• Symbiotic relationship• Both individuals of different species benefit

Flowers and Pollinators

• Pollination is a term for the sexual reproduction process in plants

• Pollinators are most commonly insects, but even birds, bats, and small mammals sometimes play a part, move pollen to other plants

• Pollinators get food, nectar

Birds and Strawberries

• Strawberry seeds must be moved away from the mother plant to germinate and grow into new individuals.

• Birds eat the berries and get food• Birds poop and distribute the seeds – seed

dispersal

Fungi and Trees

• Mycorrhizal Fungi• The fungus aids the tree in

absorbing water from the soil, increases the stability of the root system, and protects the roots from drying out and the effects of heavy metals.

• In return the tree provides sugars and starches to the fungus that the fungus uses in its metabolism.

Robert Paine

• 1966)• Examined the interaction strengths of food

webs in rocky intertidal ecosystems in the Pacific Northwest.

• KEYSTONE SPECIES

Keystone Species

• Plays a critical role in maintaining the structure of an ecological community

• Great impact on the ecosystem

Sea OttersWest Coast of North America• European and Russian trappers hunt sea otters to near extinction in the 18th

and 19th centuries.• The decline of the sea otters, which are essential to keeping sea urchins in

check, allows sea urchin populations to explode.• The burgeoning sea urchins feast on and decimate the kelp beds, which are

critical habitat for spawning fish.• Fish begin to decline for lack of spawning habitat; this affects fishermen's

catches.• Finally, an international treaty is enacted to protect sea otters.

Elephants• African grasslands• Take away the elephants, and the

grasslands, which overgrow with woody plants, convert to forests or to shrub-lands

• As the grasses disappear, so do the throngs of grazing antelopes that once massed on the grassland and, with them, go the former grassland's prides, packs and clans of great carnivores.

• The newly growing forest feeds fewer species than the former grassland.