Biotic Relationships

• All organisms fit into a:

• Habitat - the physical area in which an organism lives.

• Niche - the way of life of an organism.

• Population a group of individuals of the same species living in the same area

Biotic Relationships

All organisms engage in competition. They compete with each other for the resources needed to survive

Interactions among living organisms

Intraspecies competition - between organisms of the same species

Members of the same species will compete for:

Mates

Nesting sites

Feeding locations

Food

Water, etc

• Humans have intraspecies competion.

• Make a list of the resources that humans compete for?

Interspecies competition - between organisms of different species.

Members of DIFFERENT species will compete for:Feeding spots, FoodWaterNesting sites, etc.

For example, owls and fox both compete for mice (or food)

• Compare and contrast intraspecies (2 of the same species) and interspecies (2 different species) competition.

Predator and prey are tied together in many ways. What happens to one will

impact the other

“Eat and Be Eaten”

Predation - refers to the relationship between a predator and its prey

Changing Fortunes of Wolf And Moose Moose and wolf population fluctuations on Isle Royale depend on factors like weather, disease and possibly genetic problems. Scientists are trying to sort out reasons for the current wolf resurgence.

If the predator population is low, the numbers of the prey species will increase.

As the numbers of the predator species increase, the prey population begins to decrease. Most predator species will reproduce in larger numbers if food is abundant.

Predator – prey relationships

Herbivores (plant eaters) depend on plants to survive. Explain why carnivores (meat

eaters) depend on plants as well.

Native vs Non-Natives

Native species: one that has evolved within or migrated to an ecosystem WITHOUT humans having put it there

Nonnative species: one that humans have introduced into an ecosystem

Humans introduce nonnative plants to:

Provide food for livestock

Decorate their gardens

Reduce rates of soil erosion

Kill pests

Invasive species: nonnative species that can out-compete a native species in an ecosystem

Some nonnative species can radically change an ecosystem in a short period of time.

Invasive species will out-compete native species in the ecosystem and drastically change the relationships and habitats of other species within the ecosystem.

                                                                                                                                   

•

                                

The Desert Tamarix was introduced to America as an ornamental species. 

Large plants of Tamarix can transpire at least 200 gallons per plant each day and will often dry up ponds and streams.

Russian Knappweed

• Brought to America in 1898

• Each plant can produce up to 1200 seeds. Spread though root system of the plant.

• Plant develops

Giant African Snail

• 1st imported as pets • Can damage native

plants and crops

Cactus Moth

• Accidentally imported in cargo from the Caribbean

• Feeds on prickly pair cactus to the degree that it kills the plant

• Spreading across the US

Africanized Honeybee: The KILLER Bee!!

• Means of introduction: imported and bred with European honey bees to increase honey production

• Impact: more aggressive than European honeybees; Negative impact on honey production industry

Symbiosis• Symbiosis = "intimate living together"

between different species • Several possible types, ranging from harm

to mutual benefit. • Not clearly separated in nature;

relationship may change from beneficial to harmful as environment changes

CommensalismOne organism benefits, and the other organism (host) is not obviously affected either positively or negatively; fairly rare in nature

The anemonefish lives among the forest of tentacles of an anemone and is protected from potential predators not immune to the sting of the anemone.

Commensalism in the desert

• A fringe-toed lizard living in an abandoned rat hole, the lizard benefits from shelter, while the rat has moved on.

Mutualism

2 organisms living together and both benefit from the association

Hummingbird hawkmoth drinking from Dianthus. Moth gets water and will then spread pollen from the flower so it can reproduce

Mutualism and Plant Love

• Honeybees pollinate flowers

• The bees get food

• The plants are able to make babies!

Parasitism

One organism (parasite) obtains its nutrition from another organism (host) to the harm of the host.

The parasite usually benefits and the host is usually harmed

Desert Mistletoe living of of a

Paloverde tree

Fleas and Coyotes

Fleas feed on the coyote .

The coyote looses blood, had sores, and potentially gets diseases from the fleas

Triple Venn Summary

• Use a 3-circle Venn Diagram to compare and contrast parasitism, mutualism, and commensalism.