Biotic InteractionsBiotic Interactions

Remember: biotic = living things (in Remember: biotic = living things (in an ecosystem or environment)an ecosystem or environment)

Holiday homework, Holiday homework, revisitedrevisited

Community = many populationsCommunity = many populations

Community: all living things in an area

Population = all members of one species living in an area

Hol. Homework Cont…Hol. Homework Cont…

Ecosystem = community + abiotic factors Ecosystem = community + abiotic factors + interactions between components+ interactions between components

Naming ecosystems is usually done by Naming ecosystems is usually done by describing dominant plant types (eg. An describing dominant plant types (eg. An open grassland). Other quantifiers may open grassland). Other quantifiers may be added, such as “dense”be added, such as “dense”

Hol. Homework cont…Hol. Homework cont…

Organisms in community can be grouped Organisms in community can be grouped into producers, consumers, decomposersinto producers, consumers, decomposers

Grass: producers

Eucalypts: producers

Koalas: consumers

Snakes: consumers

Anaerobic bacteria: decomposers

Hol. Homework cont…Hol. Homework cont…

Producer: uses sunlight to build organic Producer: uses sunlight to build organic compoundscompounds

Consumer: obtain energy and nutrients Consumer: obtain energy and nutrients by eating other living (or dead) thingsby eating other living (or dead) things

Decomposers: break down organic Decomposers: break down organic matter to simple mineral nutrientsmatter to simple mineral nutrients

Hol. Homework cont…Hol. Homework cont…

Herbivores: eat plantsHerbivores: eat plants Carnivores: eat animalsCarnivores: eat animals

Omnivores: eat plants Omnivores: eat plants and animalsand animals

Detritivores: eat rotten Detritivores: eat rotten organic matterorganic matter

Consumer groups:

Hol. Homework cont…Hol. Homework cont…

Guilds are groups of organisms of Guilds are groups of organisms of different species that exploit the same different species that exploit the same food sourcefood source

Examples:Examples: Birds that eat insects from under tree Birds that eat insects from under tree

barkbark Nectar eating insectsNectar eating insects

Interactions in Interactions in ecosystemsecosystems

1.1. Between living community and Between living community and surroundingssurroundings

Eg. Inputs (oxygen, water, food) and Eg. Inputs (oxygen, water, food) and outputs (CO2, urine, faeces)outputs (CO2, urine, faeces)

This tree has been shaped by the strong coastal winds. This is an example of an interaction between a living organism and its surroundings

Thousands of fish were affected by contamination of this lake

Interactions in Interactions in communitiescommunities

May be within a species (INTRA-May be within a species (INTRA-SPECIFIC), or between different species SPECIFIC), or between different species (INTER-SPECIFIC)(INTER-SPECIFIC) CompetitionCompetition Predator-preyPredator-prey ParasitismParasitism MutualismMutualism CommensalismCommensalism

Competition Competition

A fight for resources (eg. Food, shelter A fight for resources (eg. Food, shelter etc)etc)

Inevitably, there will be a winner and a Inevitably, there will be a winner and a loser. Loser must die, leave or change loser. Loser must die, leave or change the way it uses resources (niche the way it uses resources (niche separation)separation)

Examples of competitionExamples of competitionMale antelope fight for mating resources

The penicillium fungus inhibits growth of other organisms by secreting a toxin (penicillin), as a competition for space

Faster growing seedlings will shade slower growers, preventing them from receiving adequate sunlight

Adult hippopotami will have territorial fights

Predator-prey Predator-prey relationshipsrelationships

One One species species (the (the predator) predator) kills kills another another animal animal species species (the prey)(the prey)

PredatorPredator PreyPrey-ClawsClaws-Sharp teethSharp teeth-SpeedSpeed-WebsWebs-PoisonPoison-Enhanced sense Enhanced sense organsorgans-LuresLures-Hunting strategiesHunting strategies

-CamouflageCamouflage-SpeedSpeed-Poison/repellant Poison/repellant glandsglands-Hiding strategiesHiding strategies-Safety in numbersSafety in numbers-Spikes/hard shellSpikes/hard shell-Mimicry (look like Mimicry (look like something foul)something foul)-Play deadPlay dead-Keep lookoutKeep lookout

Predators vs preyPredators vs prey

Spider weaves a web, which is sticky and catches flying insects. Spider may also have venom.

The green python hunts for tree dwelling animals, like birds, bats and small mammals at night. It senses them using heat sensing pits. It constricts its prey.

Herbivore-plant Herbivore-plant relationshiprelationship

Some plants prevent being eaten. They Some plants prevent being eaten. They may do it by:may do it by: Tasting or smelling terribleTasting or smelling terrible Having poisonous structuresHaving poisonous structures Having thorns/spikesHaving thorns/spikes Stinging with nettlesStinging with nettles

Parasite-host Parasite-host relationshipsrelationships

One organism (parasite) lives on or in One organism (parasite) lives on or in another (host). another (host).

Parasite is benefited, while host is Parasite is benefited, while host is harmed in some wayharmed in some way

ON host = exoparasiteON host = exoparasite IN host = endoparasiteIN host = endoparasite

Parasites and their hostsParasites and their hosts

Mistletoe grows on and inside a eucalypt. It takes its nutrients, but appears as a healthy part of the tree

The mouth of a parasitic flat worm, which attaches to a host’s skin (humans!!), and enters their bloodstream

A fully engorged paralysis tick. These feed on the blood of mammals, and can cause paralysis of the muscles around where it enters the body.

MutualismMutualism An interaction where both organisms An interaction where both organisms

benefit in some waybenefit in some way

The mistletoe bird eats mistletoe berries. Before they defecate, they turn their bodies parallel to the branch, which means the seed does not fall to the ground, but gets lodged in the branch

Bacteria living in the lure of an anglerfish get a stable environment, while the anglerfish is a more efficient predator

Nitrogen fixing bacteria lives in the root nodules of some plants. These bacterium remove nitrogen from the air and turn it into a usable compound for the plant.

CommensalismCommensalism

One member of the interaction benefits, One member of the interaction benefits, while the other is neither harmed nor while the other is neither harmed nor benefited.benefited.

Anenome fish make their home within stinging anenomes. They are immune to the sting, but it keeps predators away. The anenome, though, will have the same quality of life with or without the anenome fish

SymbiosisSymbiosis

These interactions are called SYMBIOSISThese interactions are called SYMBIOSIS

InteractionInteraction Species 1Species 1 Species 2Species 2

ParasitismParasitism Parasite: Parasite: benefitsbenefits

Host: harmedHost: harmed

MutualismMutualism benefitsbenefits BenefitsBenefits

CommensalismCommensalism benefitsbenefits No harm or No harm or benefitbenefit

ActivitiesActivities

Glossary words: inter-specific, intra-Glossary words: inter-specific, intra-specific, competition, predator, prey, specific, competition, predator, prey, mimicry, camouflage, parasite, host, mimicry, camouflage, parasite, host, exoparasite, endoparasite, mutualism, exoparasite, endoparasite, mutualism, nitrogen fixing bacteria, commensalism, nitrogen fixing bacteria, commensalism, symbiosis.symbiosis.

Quick Check pg 433Quick Check pg 433