Bellringer 12.3Copy the following root words into your notebook.•A- : without, not (ex: abiotic)•Auto- : self (ex: autotroph)•Bio- : life (ex: biology)•Carn- : meat (ex: carnivore)•Eco- : where one lives, home (ex: ecosystem)•Herb- : plant (ex: herbivore)•Hetero- : different (ex: heterotroph)•-logy : study of (ex: biology, ecology)•Photo- : light (ex: photosynthesis)• -troph : to feed or eat (ex: autotroph)•-vore : devour (eat) (ex: carnivore, herbivore)

Community Relationships

1. SymbiosisA close relationship between two organisms of different species in which at least one organism benefits.

benefit is usually one of the following: food, protection, habitat, or pollination

Includes: mutualism, commensalism, and parasitism.

Mutualism (+,+)Relationship in which both organisms benefits

Angiosperm (plant with flowers) and insectMany plants depend on pollinators for their reproduction. They provide nectar to attract these pollinators. The pollinator gets fed and the plants reproduce!

Bacteria and plants Bacteria in the nodules of some plants can take nitrogen gas from the atmosphere and turn it into a form that can be used by the plant. In return, the plant protects the bacteria from harmful oxygen and the bacteria get food from the plant.

nodule

Green algae and fungus = lichenLichen consist of a fungus with a photosynthetic green algae.The algae provides food for both of them and the fungus provides a habitat for the algae.

Commensalism (+,0)Relationship where one organism benefits and the other is not affected.

Few examples exist because of the difficulty of showing that one of the organisms is not affected by the other.

Cattle and egretThe cattle stir up grasshoppers and other insects that the egret likes to eat. There are no apparent benefits to the cow.

Shark and remoraThe remora benefits by getting food from the shark’s meal. There’s no apparent benefit to the shark.

Whale and barnacleThe barnacle larvae swim around and attach to the whale, where the adult forms. This habitat is a good one for providing food. The whale does not appear to be harmed.

Parasitism (+,-)Relationship where one organism benefits and the other is harmed.

Parasites rarely kill their hosts because to do so would ultimately harm the parasite!

Wasp and caterpillarAdult wasps insert their eggs beneath the skin of the hornworm larva. The eggs hatch and the young feed on hornworm until they pupate. Although the parasite is harmful to the worm, it is important in controlling hornworms in agriculture.

Mistletoe and treeMistletoe lives off the branches and stems of other trees. It can photosynthesize a little, but not enough to meet its needs. The tree can be very harmed.

mistletoe

Heartworms and dogsThe worm larvae are transferred from dog to dog through the bite of an infected mosquito. The mosquito sucks larval heartworms with blood from an infected dog. The mosquito then bites another dog and transfers these microscopic larvae as it bites. During the next few months, these larvae migrate through dogs bodies arriving at the heart, where they become adults.

The crab Lybia tessellata carries a pair of sea anemones on its claws. The crab uses the sea anemone’s stinging tentacles as protection and the sea anemone obtains small food particles released by the crab as it feeds.Which type of symbiotic relationship does this best illustrate?A. CommensalismB. MutualismC. ParasitismD. Predation

2. CompetitionWhen two organisms attempt to use the same space and resources at the same time.

These two flowering plants are competing for the same space which means both of them are harmed.

Competitive Exclusion PrincipleNo two species can occupy the same niche in the same habitat at the same time.

Introduced species• A species that is not native to

an area• AKA: nonnative, alien, or

exotic species• Creates problems in

ecosystems because there are no natural predators to keep the population size down

• Frequently results in the competitive exclusion of a native species

• Ex: kudzu – Introduced to the US in 1876. It outcompetes other native plants so they don’t have a place to grow.

Invasive species•A species is considered invasive if it

causes damage to an established ecosystem.

•All invasive species are exotic, but not all exotic species are invasive.

3. PredationWhen one organism benefits by killing and consuming another organism.

predator hunterprey hunted

Spider and insectIn this predator-prey relationship, the spider is eating an insect that it has trapped.

Cheetah and grazing animal

The relationship between predator and prey populations can greatly affect the population size of both.

This is especially true when the relationship is exclusive.

-----Predator/prey simulation-----

•More prey = more predators▫Think: more prey

is more food!

•# of prey always increases first

•Less prey = less predators